# Pound for pound, is reduction in bodyweight and bike weight equal, performance wise?



## krott5333 (Oct 2, 2009)

Would losing 5 pounds of body weight have the same effect as riding a bike 5 lbs lighter?


----------



## CleavesF (Dec 31, 2007)

no, it's much much better.


----------



## tihsepa (Nov 27, 2008)

Would pushing your bike be any easier if you were 5 pounds lighter?
No.

Would pushing your bike be any easier if it was 5 pounds lighter and you were 5 pounds heavier?

Yep.

Lighter bike is better.


----------



## Retro Grouch (Apr 30, 2002)

Losing body weight pays much more dividends compared to bike weight. Unless of course you are already like 5'10 and 130 pounds are train/ride hard to begin with.


----------



## krott5333 (Oct 2, 2009)

tihsepa said:


> Would pushing your bike be any easier if you were 5 pounds lighter?
> No.
> 
> Would pushing your bike be any easier if it was 5 pounds lighter and you were 5 pounds heavier?
> ...


so confusing :mad2:


----------



## thebikingcello (Feb 3, 2011)

body weight for sure. YOU are the one moving the bike. Gain in leg muscle mass makes the bike feel lighter so even MORE cost effective. But if you want to drop some $$$ on your bike for weight savings, get a nice set of wheels for the best performance to weight ratio.


----------



## Blackss06 (Feb 26, 2011)

I think gaining 5 pounds of muscle would be more beneficial then either, especially if any of it was gained in your legs.


----------



## Kerry Irons (Feb 25, 2002)

*Physics 101?*



tihsepa said:


> Would pushing your bike be any easier if you were 5 pounds lighter?
> No.
> 
> Would pushing your bike be any easier if it was 5 pounds lighter and you were 5 pounds heavier?
> ...


Seldom does one get to see such a misrepresentation of the physics of cycling. Either that or 1) you're joking, 2) this is a troll.

To the OP: except for a small difference in acceleration if the weight saved is totally in the wheels, there is zero difference between body weight and bike weight.


----------



## nOOky (Mar 20, 2009)

The answer is that it depends. Losing 5 lbs on a bike feels different if it's the wheels or the entire frame and components. You might be able to tell, you might not.
Losing 5 lbs on you might matter if it's lost from the upper body, if you lost 5 lbs of leg muscle you might be weaker on the bike. You might train like a demon, lose 5 lbs of upper body fat, and increase your leg muscles by 5 lbs. Huge difference for the same body weight.
Then again you might incorporate some interval sessions into your routine instead of just going out and hammering all the time and stay the same weight and still be faster.
You could ride 75 miles on a hot day and lose 5 lbs, and lose the weight of the water bottles because you've drank it all, would you then be faster?


----------



## GetReal (Jul 26, 2010)

Depends. Being a bigger rider, losing 5 lbs of bodyweight is more benefical simply for the fact it took some training to get there.


----------



## scryan (Jan 24, 2011)

Kerry Irons said:


> Seldom does one get to see such a misrepresentation of the physics of cycling. Either that or 1) you're joking, 2) this is a troll.
> 
> To the OP: except for a small difference in acceleration if the weight saved is totally in the wheels, there is zero difference between body weight and bike weight.


He is kinda right in a way, though the results are probably pretty minor and maybe not exactly what he means....

But like any suspension system its better to have as little unsprung weight as possible. Better to have that weight supported and controlled by your legs then having to swing it back and forth underneath you . 

But on the other side, most probably assume you will lose that 5 lbs by riding it off, and that work will definitely make you faster...

So it depends on what better is, and what we are really looking at.

Feel and nimbleness, bike weight more important. 
Climbing, probably doesn't matter unless you lose it from wheels.
Outright speed, putting in work to lose weight will make you faster then most weight changes unless they are very dramatic.... but that isn't really a physics thing.


----------



## maximum7 (Apr 24, 2008)

If you take it off the bike, it stays off. 

Unless your already thin, 5 lbs. off your body won't matter that much. Most people fluctuate a couple of pounds throughout the week.


----------



## MR_GRUMPY (Aug 21, 2002)

krott5333 said:


> Would losing 5 pounds of body weight have the same effect as riding a bike 5 lbs lighter?


Yes, except that you would save a hell of a lot of money.

Anybody can lose 5 pounds if they really want to.

The problem is that many people want a lower total bike/rider weight without the effort it takes to shave off some lard. For them a 15 pound makes sense. For people who live in the "real world", a 15 pound bike makes sense for a Cat 2.
.
.
.


----------



## malanb (Oct 26, 2009)

Blackss06 said:


> I think gaining 5 pounds of muscle would be more beneficial then either, especially if any of it was gained in your legs.


eeeeh not. well it depends. what kind of muscle, your wieght. etc


----------



## ZoSoSwiM (Mar 7, 2008)

You don't notice the lost weight until you need to carry it..

case in point...

I've lost over 50ish pounds and am currently at the lightest I've been in many many years.. I put was carrying a backpack filled with stuff a while ago and suddenly realized that as heavy as the pack was it was still LESS than what I had lost. Walking up stairs with all that on my back wasn't fun.. Really made me appreciate how much I've lost. 

On that note losing it from your body is cheaper and going to help you the most in the long run.


----------



## Damitletsride! (Oct 19, 2007)

If you lost 5lbs of body fat you would probably get a lot fitter in the process of losing it which will make you a lot faster. Having a light bike won't make you fast, but it helps.


----------



## me_not_you (May 22, 2010)

I think there are some aspects that people are not talking about. When I loose weight(regardless of my fitness level), I notice that I feel better, don't get as tired and don't overheat as much. How does this quantify when riding a bike? Who knows? But I personally would give the edge in performance to when the person looses 5 lbs.


----------



## Hank Stamper (Sep 9, 2009)

My body weight is constantly going up and down by 5 pounds (okay, more like 3-4 but) in a very short time (like over night) and I don't notice any difference.

I don't notice any difference between full or empty water bottles either (3 pounds swings).
Seems about the same to me (which for all practical purposes is: nothing).

If you really want to split hairs you could look into the aerodynamic benefits of where the weight (thus size/bulk) is reduced but that would be a little outrageous.
And off course I'm assuming we're not factoring in fitness impact or impact on watts generated per pound ect here.


----------



## Len J (Jan 28, 2004)

tihsepa said:


> Would pushing your bike be any easier if you were 5 pounds lighter?
> No.
> 
> Would pushing your bike be any easier if it was 5 pounds lighter and you were 5 pounds heavier?
> ...


You forgot the sarcastic emoticons.

Len


----------



## icsloppl (Aug 25, 2009)

Scryan is correct. From gravity's point of view you and the bike are tightly coupled, so the location of mass doesn't matter.

However, to some degree your tires/wheels/frame act as a suspension system. Some manufacturers, such as Canyon and now Cannondale, are trying to control and integrate this into their frame designs.

As Mr. Irons points out, if the weight is rotational, its effect is much greater, up to 4x so depending on how far it is from the rotation axis.


----------



## Hank Stamper (Sep 9, 2009)

icsloppl said:


> Scryan is correct. From gravity's point of view you and the bike are tightly coupled, so the location of mass doesn't matter.
> 
> However, to some degree your tires/wheels/frame act as a suspension system. *Some manufacturers, such as Canyon and now Cannondale, are trying to control and integrate this into their frame designs.*
> As Mr. Irons points out, if the weight is rotational, its effect is much greater, up to 4x so depending on how far it is from the rotation axis.


Care to eleborate? I understand how a frame acts as a suspension but don't understand how that's not already integrated into the design.


----------



## majura (Apr 21, 2007)

krott5333 said:


> Would losing 5 pounds of body weight have the same effect as riding a bike 5 lbs lighter?


Technically you should refer to it as mass rather than weight as gravity isn't the only force involved here. How much is your body and bike's mass?


----------



## bigrider (Jun 27, 2002)

tihsepa said:


> Would pushing your bike be any easier if you were 5 pounds lighter?
> No.
> 
> Would pushing your bike be any easier if it was 5 pounds lighter and you were 5 pounds heavier?
> ...



Dear Duke Physics Major,

Keep studying.

Sincerely,

Maryland Terps Fan


----------



## woodys737 (Dec 31, 2005)

Hank Stamper said:


> My body weight is constantly going up and down by 5 pounds (okay, more like 3-4 but) in a very short time (like over night) and I don't notice any difference.
> 
> I don't notice any difference between full or empty water bottles either (3 pounds swings).
> Seems about the same to me (which for all practical purposes is: nothing).
> ...


+1. I've lost 10 pounds via eating a bit smarter (imo) and was hoping to be able to notice a difference on the climbs which I don't. For the vast majority of us week end warriors I believe time on the bike will produce vastly more noticeable gains than losing pounds off the body/bike system. This coming from a closet WW.

edit: This probably should be qualified for guys like me who have never been over weight. If you have 50lbs to shed then I would imagine you will see a noticeable difference in climbing performance just from the weight loss.


----------



## robdamanii (Feb 13, 2006)

If you take 5 pounds off your bike, you'll lighten your wallet by 4 ounces, and you'll be able to add about 4 pounds, 12 ounces of bacon to your diet.


----------



## Dr_John (Oct 11, 2005)

> Care to eleborate?


Canyon and Cannondale have cornered the market on 'laterally stiff, yet vertically compliant' frame designs.


----------



## AJL (Jul 9, 2009)

Kerry Irons said:


> Seldom does one get to see such a misrepresentation of the physics of cycling. Either that or 1) you're joking, 2) this is a troll.
> 
> To the OP: except for a small difference in acceleration if the weight saved is totally in the wheels, there is zero difference between body weight and bike weight.


^^^ THIS!

Now everyone else go away, nothing more to see here. The OP's question has been answered.


----------



## ToF (Jan 18, 2008)

This weekend I was carrying about 20 pounds of picnic food in my panniers, 5 of which I probably ended up eating, 3 which was probably "eliminated," and 15 which I shared with my associates. Some of it was potato salad, and I had bad breath because of the onions and eggs. My average speed was decreased by 7% on the way home, but that might be because I stopped for coffee. hth


----------



## Allez Rouge (Jan 1, 1970)

woodys737 said:


> If you have 50lbs to shed then I would imagine you will see a noticeable difference in climbing performance just from the weight loss.


Boy Howdy. Two years ago, over a period of 10 months, I lost 74 lbs -- from a high of 242, all the way down to 168. I went from being the absolute worst climber in our club to one of the best two or three. I say that not to boast (well ... maybe a little ) but as a simple statement of fact. Before I lost the weight, I was pathetic. I could usually hold my own on the flats, but I hated even the tiniest of hills. I'd be riding with the group as we'd start up a small rise equivalent to a freeway overpass, and by the time everyone else went over the top, I'd be maybe a third of the way up. Maybe.

The guys I ride with sometimes comment on how much stronger I've gotten on the climbs. I tell them to drape three 25 pound bags of dog food over their top tubes and go for a ride. That's the difference between where I was and where I am now.

Well, not quite _now_, because over the past winter I gained back about eight of those pounds, and haven't yet gotten serious about getting them back off. To reinforce your other point, it hasn't made a noticeable difference. The big weight loss made me eager to ride more, and spending more time on the bike made me a stronger rider, so that now a few pounds one way or the other doesn't seem to affect my performance all that much.


----------



## jswilson64 (May 20, 2008)

Losing 5 lbs will make many facets of your life, including riding, better. Lightening your bike by 5 lbs will make riding better.


----------



## teknohippy (May 20, 2011)

Most importantly your Significant Other is likely to be more pleased that you lost 5lbs of bodyweight as opposed to losing the cash spent on removing 5lbs of bike weight.

"Does my arse look big in this bike dearest?"

*grins*


----------



## azpeterb (Jun 1, 2006)

ToF said:


> This weekend I was carrying about 20 pounds of picnic food in my panniers, 5 of which I probably ended up eating, 3 which was probably "eliminated," and 15 which I shared with my associates. Some of it was potato salad, and I had bad breath because of the onions and eggs. My average speed was decreased by 7% on the way home, but that might be because I stopped for coffee. hth


But you didn't factor in the flatulent propulsitory effects that you experienced after eating hard boiled eggs. That would have increased your average speed.


----------



## rydbyk (Feb 17, 2010)

spend away...forget fitness:thumbsup: 

really though, too many variables to say "yes" or "no". in most cases, you will be faster when losing 5 lbs of body fat v. 5 lbs off bike.

some people should NOT lose 5 lbs, as they are too thin already..


----------



## Xcelerate (Mar 23, 2011)

If the bike weight is coming from the wheels it can make a big difference, otherwise the only difference you would probably notice from losing the weight in fat is that you are fitter and can thus ride better.

Although, if you lose weight you won't go as fast down a hill beginning from a standstill at the top: the ratio of bike+your weight to wheel weight decreases.


----------



## Reynolds531 (Nov 8, 2002)

krott5333 said:


> Would losing 5 pounds of body weight have the same effect as riding a bike 5 lbs lighter?


I'd much rather be a 182 lb rider on an 18 lb bike than a 187 lb rider on a 13 lb bike.


----------



## woodys737 (Dec 31, 2005)

Allez Rouge said:


> Boy Howdy. Two years ago, over a period of 10 months, I lost 74 lbs -- from a high of 242, all the way down to 168. I went from being the absolute worst climber in our club to one of the best two or three. I say that not to boast (well ... maybe a little ) but as a simple statement of fact. Before I lost the weight, I was pathetic. I could usually hold my own on the flats, but I hated even the tiniest of hills. I'd be riding with the group as we'd start up a small rise equivalent to a freeway overpass, and by the time everyone else went over the top, I'd be maybe a third of the way up. Maybe.
> 
> The guys I ride with sometimes comment on how much stronger I've gotten on the climbs. I tell them to drape three 25 pound bags of dog food over their top tubes and go for a ride. That's the difference between where I was and where I am now.
> 
> Well, not quite _now_, because over the past winter I gained back about eight of those pounds, and haven't yet gotten serious about getting them back off. To reinforce your other point, it hasn't made a noticeable difference. The big weight loss made me eager to ride more, and spending more time on the bike made me a stronger rider, so that now a few pounds one way or the other doesn't seem to affect my performance all that much.


Very inspiring! 10 has been enough of a challenge for me. I can not imagine 70+ lbs!


----------



## Reynolds531 (Nov 8, 2002)

icsloppl said:


> if the weight is rotational, its effect is much greater, up to 4x so depending on how far it is from the rotation axis.


2X at most. not 4X.


----------



## Len J (Jan 28, 2004)

Reynolds531 said:


> 2X at most. not 4X.


And only predominatly during acceleration.

Len


----------



## rward325 (Sep 22, 2008)

Reynolds531 said:


> I'd much rather be a 182 lb rider on an 18 lb bike than a 187 lb rider on a 13 lb bike.


That is rather ambiguous without stating your height. If I am 5'6" and 187 lbs I might take the 13lb bike!


----------



## ziscwg (Apr 19, 2010)

krott5333 said:


> Would losing 5 pounds of body weight have the same effect as riding a bike 5 lbs lighter?


well, losing body weight is nearly free. All it takes is will power. 

Losing 5 lbs off the bike would be like $5000 according to those testrider.com guys as I remember. It was something like for every $1000 you spend on your bike, it's about a pound less. 

I think the better question is where would you benefit the most.

I think your on the right line of thinking here. Work on the bikes engine more than the bike. It takes time, not money. If you put Lance Armstrong on a $1000 entry level bike and you on one of those new Cannondale EVO Ulitmates at 10.9 lbs, who do you think is going to win in a race?


----------



## jerrycan42 (Aug 18, 2010)

I know in my case, I'm 40 lbs overweight so I could stand to lose 25lbs, but my bike would disappear if it lost 25lbs...


----------



## seacoaster (May 9, 2010)

I asked my LBS if I would be further ahead to lose 5 lbs. or to spend $8,000 on a new bike that weighs 5 lbs. less than what I'm riding now. They told me to buy the new bike, so it must be better to ride a lighter bike than lose weight.


----------



## woodys737 (Dec 31, 2005)

seacoaster said:


> I asked my LBS if I would be further ahead to lose 5 lbs. or to spend $8,000 on a new bike that weighs 5 lbs. less than what I'm riding now. They told me to buy the new bike, so it must be better to ride a lighter bike than lose weight.


Ha! 

IMHO, I work for the worst airline ever but in the interest of self preservation I still ask people to buy tickets from us.:idea:


----------



## Pirx (Aug 9, 2009)

Xcelerate said:


> If the bike weight is coming from the wheels it can make a big difference,


That's a bit of a red herring, too. Yes, if you loose 5lbs on the rims, that would make quite a difference, but you'll be hard pressed to find wheels that are heavy enough to make that a possibility... The fact of the matter is that there is not a huge difference in mass between rims. So, yeah, maybe you can drop 100grams on your rims, which will make no meaningful difference for most people. If you race professionally, and for money, then that's a different matter, but for most of us mere mortals is doesn't matter at all.


----------



## DonDenver (May 30, 2007)

Funny as I’ve always thought the loss of body weight and bike weight goes hand in hand anyway as dropping total weight is so proportional and closely timed. A causality dilemma perhaps since both are equally important considering which initial weight loss better spurs the other. 

Does a nice new lightweight bike better motivate body weight loss or does daily cycling’s benefits cause us to drop the dollars squeezing the grams out of the bike? And as I think about this, it would be a weird subject to anyone not part of this forum. 

Certainly we’re a silly lot...but at least a healthy bunch.


----------



## Pirx (Aug 9, 2009)

icsloppl said:


> if the weight is rotational, its effect is much greater, up to 4x so depending on how far it is from the rotation axis.


That's a meaningless statement unless you say what effect you are talking about: If you are talking about climb performance, then it doesn't make one wit of a difference where the weight is. If you are talking acceleration, then, yes, rotational weight makes more of a difference, but as I said above, for most of us that difference, realistically, is so tiny that there's no point even thinking about it.


----------



## Reynolds531 (Nov 8, 2002)

woodys737 said:


> Ha!
> 
> IMHO, I work for the worst airline ever but in the interest of self preservation I still ask people to buy tickets from us.:idea:


Most of us are w hores


----------



## Xcelerate (Mar 23, 2011)

I did a calculation once... I forget what the equation was (I'll see if I can find it) but basically the most extreme case made a difference of 1 mph. And you must consider this energy doesn't just come for free -- it's put into the bike going up the hill. So there really isn't any advantage except that a light wheelset will allow you to accelerate quicker.

EDIT: This calculation excluded aerodynamics which is a MUCH greater factor than anything weight-related.


----------



## Spinfinity (Feb 3, 2004)

I'd say accelerating it's no different (see Kerry Irons post).

Having gained and lost and gained and lost a good few pounds in my life, I'd say I could ride faster at my aerobic threshhold if I'm lighter, than I could on a lighter bike.


----------



## Xcelerate (Mar 23, 2011)

Yes acceleration is different. As an extreme example, imagine two 30 pound bikes. One has a total of 28 pounds for the wheels and 2 pounds for the frame, and the other has 2 pounds for the wheels and 28 pounds for the frame. The second bike will accelerate much more easily.

If, on the other hand, you meant there is no *practical* difference in real-world wheelsets then you are correct.


----------



## jsk0307 (Apr 25, 2011)

I noticed a big difference dropping weight. I was at 332lbs and now down to 215. I keep telling myself that if I can drop another 25-30 I could see an even bigger improvement. I've been stuck at a plateau for a few months now.


----------



## GetReal (Jul 26, 2010)

MR_GRUMPY said:


> The problem is that many people want a lower total bike/rider weight without the effort it takes to shave off some lard. For them a 15 pound makes sense. For people who live in the "real world", a 15 pound bike makes sense for a Cat 2..


These threads crack me up.I know too many bozos out there looking for a 15 lb bike to climb freeway overpasses.


----------



## Kerry Irons (Feb 25, 2002)

*More misinformation*



scryan said:


> He is kinda right in a way, though the results are probably pretty minor and maybe not exactly what he means....
> 
> But like any suspension system its better to have as little unsprung weight as possible. Better to have that weight supported and controlled by your legs then having to swing it back and forth underneath you .
> 
> ...


Well, the concept of unsprung weight is pretty much meaningless on a bicycle because we're not talking damped shock absorbers, and the question was not about these effects anyway. Take 10% off your score.

Weight is weight when climbing, and it makes no difference whether it comes from lighter wheels or empty water bottles. Take another 10% off your score.

Lower weight will make you faster on the flats, just not very much faster since its only impact is on tire and bearing rolling resistance. Take another 10% off your score.

I hope you had a perfect paper before you started this, because you are already down to 70% on your physics test.


----------



## Xcelerate (Mar 23, 2011)

Kerry Irons said:


> Well, the concept of unsprung weight is pretty much meaningless on a bicycle because we're not talking damped shock absorbers, and the question was not about these effects anyway. Take 10% off your score.
> 
> Weight is weight when climbing, and it makes no difference whether it comes from lighter wheels or empty water bottles. Take another 10% off your score.
> 
> ...


Ok, now I don't agree with what that guy wrote, but I have been on RBR for a few months now and am dying to understand something. I'm not singling you out, because a ton of people on here do it, but why must you reply so condescendingly to this guy? An imaginary physics test that he's failing? I mean maybe it's a joke and the humor just isn't translating for me, but I feel like you could have gotten your point across in a much friendlier manner.


----------



## TomH (Oct 6, 2008)

Put a 50lbs backpack on and run in zigzags. Its not too hard. Now put 50lbs on your head and hold it and run zigzags. Its much harder. Try putting 25lbs on each foot and doing it, its even harder. 

5lbs is nothing, but trying to use that as some sweeping rule doesnt make sense. A strong 150lbs rider on a 70lbs bike isnt going to be able to keep up with a strong 200lbs rider on a 20lbs bike. The 70lbs bike will feel like a lumbering mess. Its too much to throw around. 

Unless you ride your bike nearly motionless in a perfectly straight line with a smooth cadence, you'll feel bike weight.


----------



## ToF (Jan 18, 2008)

jsk0307 said:


> I noticed a big difference dropping weight. I was at 332lbs and now down to 215. I keep telling myself that if I can drop another 25-30 I could see an even bigger improvement. I've been stuck at a plateau for a few months now.


Nice!


----------



## pacificaslim (Sep 10, 2008)

If we were talking about a mountain bike or cyclocross bike, where I often want to move the bike independent of my body, I'd rather have the lighter bike. It's more maneuverable and therefore less tiring by the end of the ride.


----------



## MarshallH1987 (Jun 17, 2009)

Body weight loss is better, VO2 max is an important thing, that is a measurement of your body's ability to utilize oxygen per body weight per minute. Drop body weight and you increase your VO2, so it is more than just a loss in weight.


----------



## teknohippy (May 20, 2011)

MarshallH1987 said:


> Body weight loss is better, VO2 max is an important thing, that is a measurement of your body's ability to utilize oxygen per body weight per minute. Drop body weight and you increase your VO2, so it is more than just a loss in weight.


What's a good way to increase VO2 for a commuting cyclist?


----------



## Salsa_Lover (Jul 6, 2008)

Xcelerate said:


> Ok, now I don't agree with what that guy wrote, but I have been on RBR for a few months now and am dying to understand something. I'm not singling you out, because a ton of people on here do it, but why must you reply so condescendingly to this guy? An imaginary physics test that he's failing? I mean maybe it's a joke and the humor just isn't translating for me, but I feel like you could have gotten your point across in a much friendlier manner.


 a n00b daring to challenge Kerry Irons ?


----------



## Kerry Irons (Feb 25, 2002)

*Reasoning*



Xcelerate said:


> Ok, now I don't agree with what that guy wrote, but I have been on RBR for a few months now and am dying to understand something. I'm not singling you out, because a ton of people on here do it, but why must you reply so condescendingly to this guy? An imaginary physics test that he's failing? I mean maybe it's a joke and the humor just isn't translating for me, but I feel like you could have gotten your point across in a much friendlier manner.


Perhaps if you had seen the number of completely bogus physics claims on this board over the past decade you would better understand my approach. I agree that I could have been more gentle, but history has taught me that many folks need a 2x4 to get them to look at their lack of understanding simple physics.

It's one thing to ask how things work relative to bicycles, but to come up with three completely incorrect interpretations of the physics deserves to be pointed out. Bicycling is chock full of these completely incorrect understandings, and to see them propagated is beyond annoying. People spend large amounts of money chasing these falsehoods.

tihsepa started with an utterly incorrect statement, and then scryan compounded it by saying "He is kinda right in a way." That is NOT how physics works. At least not Newtonian physics.


----------



## MR_GRUMPY (Aug 21, 2002)

On the other hand, I have no problem being condescending towards people who are 100% wrong.

Weight is weight.....

End of discussion.

Fin.


----------



## Xcelerate (Mar 23, 2011)

Hmm.. a decade huh? You know what would be interesting would be a sticky thread explaining the basic physics involved in cycling -- the relative impact of air vs tire resistance, links to power and gear calculators, links to studies on tire width. You could have one big thread with peer-reviewed information listed all at the top!

And then you could direct the ill-informed to such a thread instead of getting out your 2x4.

Just an idea anyway.

EDIT: I just noticed you're a chemical engineer (Like me! But you seem to have a lot more experience ). Every time I see a curt or sarcastic reply on this website, I Google the person and end up finding out they are an engineer. I suppose I'm not old enough yet to get upset at internet stupidity. So ignore my advice and proceed with your 2x4 whacking!

EDIT 2: Sorry, I'm a bit of a creeper. You seem to have done a good number of experiments involving cycling (wheel wear, iron), so a sticky with all this information could be a great asset to the community.


----------



## pbraun (Mar 30, 2002)

I agree on the physics of gravity not caring whether it's bike weight or body weight, but your body knows. One pound of fat contains about 3.5 miles of blood vessels and those cells need oxygen and nutrients. Assuming you have 5 lbs of excess fat, it's better to lose the weight off your carcass than off the bike.


----------



## Pirx (Aug 9, 2009)

pbraun said:


> I agree on the physics of gravity not caring whether it's bike weight or body weight, but your body knows. One pound of fat contains about 3.5 miles of blood vessels and those cells need oxygen and nutrients. Assuming you have 5 lbs of excess fat, it's better to lose the weight off your carcass than off the bike.


Hmm, yeah, now that you mention it, there's very few blood vessels on my bike. Most of the time, anyway, with the exception of a few accidents now and then... 

Seriously though, while I have no doubts that those fat cells need nutrients, too, the amount of energy they require should be tiny.


----------



## mreams99 (Feb 25, 2009)

If you're in the business of selling bikes and components, then a lighter bike is better.


----------



## pacificaslim (Sep 10, 2008)

For those who would rather have a lighter rider and heavier bike and believe in the "total package weight" theory of performance: how far are you willing to take that? Would you expect similar riding experience for a 120 lb. rider on an 95 lb. bicycle as a 200 lb. rider on 15 lb. bicycle? If not, at what weight levels does your "lighter rider/heavier bike" preference break down? And why, if it breaks down at some point, do you still hold your original thesis of "total package" and prefer lighter rider than lighter bike?

(and btw, forget about the muscle difference between the 200 lb. and 120 lb. rider: other threads have argued pretty convincingly, and pro tour cyclists are good evidence as well, that it does not take much muscle or strength at all to ride a bicycle).


----------



## Kontact (Apr 1, 2011)

I would recommend that you all re-read thipsea's post. It doesn't actually answer the question, but it is internally logical. It just completely misses that the bike being pushed has a rider on it!


Anyhoo, people are motors, the bike is a chasis. You can have unnecessarily heavy motors (like a fat rider or a steel engine), or you can have efficient motors that produce a lot of horsepower for their weight and frontal area. For people of the same body composition, the larger person produces more wattage per frontal area than a smaller guy and is faster on straights, and the smaller guy has a larger lung capacity per pound than the big guy, helping on climbs.

The bike is the bike. Unless making it lighter makes it somehow less efficient (like a too-flexible frame or wheels), the lightness doesn't come with any of the tradeoffs that changing motor mass does.

If you have fat, get rid of it - it isn't helping any part of your life. If you have muscle, consider whether it is helping you fight the wind or slowing your climb before you change it. If you can make your bike lighter, do it - it feels good and always helps you climb.


----------



## woodys737 (Dec 31, 2005)

pacificaslim said:


> For those who would rather have a lighter rider and heavier bike and believe in the "total package weight" theory of performance: how far are you willing to take that? Would you expect similar riding experience for a 120 lb. rider on an 95 lb. bicycle as a 200 lb. rider on 15 lb. bicycle? If not, at what weight levels does your "lighter rider/heavier bike" preference break down? And why, if it breaks down at some point, do you still hold your original thesis of "total package" and prefer lighter rider than lighter bike?
> 
> (and btw, forget about the muscle difference between the 200 lb. and 120 lb. rider: other threads have argued pretty convincingly, and pro tour cyclists are good evidence as well, that it does not take much muscle or strength at all to ride a bicycle).


Are the 200lbs rider and the 120lbs rider generating the same power?


----------



## Kerry Irons (Feb 25, 2002)

*Denying physics*



pacificaslim said:


> For those who would rather have a lighter rider and heavier bike and believe in the "total package weight" theory of performance: how far are you willing to take that? Would you expect similar riding experience for a 120 lb. rider on an 95 lb. bicycle as a 200 lb. rider on 15 lb. bicycle? If not, at what weight levels does your "lighter rider/heavier bike" preference break down? And why, if it breaks down at some point, do you still hold your original thesis of "total package" and prefer lighter rider than lighter bike?
> 
> (and btw, forget about the muscle difference between the 200 lb. and 120 lb. rider: other threads have argued pretty convincingly, and pro tour cyclists are good evidence as well, that it does not take much muscle or strength at all to ride a bicycle).


It's not about muscle strength, it's about power output. If both riders have the same power output, they will go the same speed up the hill. If you can demonstrate otherwise, you will replace Isaac Newton in the physics hall of fame.


----------



## pacificaslim (Sep 10, 2008)

BTW, I'm not trying to rationalize being overweight: I'm 6'0", 145 with under 10% body fat. 

There is a lot more to riding a bike than power output. Unless you are talking about riding a bike attached to an indoor trainer. In the real world, we must "ride" the bike. That's why I always prefer to have a lighter bike to maneuver around and don't like this "total package" idea. Where the weight is matters - the closer it is to one's center of gravity (a beer belly for example) the less it takes to move, right? And conversely, weight further away from the core is like carrying weight on the end of a yardstick - takes much more force to lift/move, right?

This is much more obvious with mountain bikes and cyclocross as I mentioned before, but I believe it also holds for road cycling. Easy example: which is easier, bunnyhopping a bike over a storm drain when you have 30 lbs. in a backpack on your back (analogous to being overweight) or having that 30 lbs. in panniers on the bike?


----------



## Kontact (Apr 1, 2011)

Kerry Irons said:


> It's not about muscle strength, it's about power output. If both riders have the same power output, they will go the same speed up the hill. If you can demonstrate otherwise, you will replace Isaac Newton in the physics hall of fame.


Power output varies by activity, in part due to something much like "muscle strength". Climbing specialists are rarely overall winners, for instance.


----------



## Lotophage (Feb 19, 2011)

Here's an easy way to think about it:

Take 2 people- one loses 5 pounds off the bike, one loses 5 pounds off their ass. 

to lose 5 pounds off your bike, you don't have to do much other than search the internet and order parts.

to lose 5 pounds off your ass, you have to ride more and eat better. 

So, after the loss has been achieved, who's gonna be stronger? the guy who rode the 5 pounds off or the guy who bought lighter wheels?

You don't really notice that the weight is gone. I lost more than 50 pounds and really, didn't seem to notice any difference except that I was riding farther and faster than ever before, but that's just because I was in better shape...


----------



## AJL (Jul 9, 2009)

You guys do realize that _*Reductio ad absurdum*_ arguments do not make your case, right?


----------



## Xcelerate (Mar 23, 2011)

Kerry Irons said:


> It's not about muscle strength, it's about power output *at the cranks*. If both riders have the same power output, they will go the same speed up the hill. If you can demonstrate otherwise, you will replace Isaac Newton in the physics hall of fame.


Added the bold. I think there is some confusion here concerning metabolic power (stored body energy converted into heat) vs mechanical power delivered to the cranks. In running, this is called ... (drumroll) ... running economy. I don't know what it's called in cycling.


----------



## Xcelerate (Mar 23, 2011)

Kerry Irons said:


> I think you are the only one who might be confused. When cyclists talk about power, they are referring EXCLUSIVELY to what is delivered, either to the cranks or the rear wheel depending on what power measuring device is employed. Absent a power measuring device, fairly accurate power estimates can be done with a simple calculation knowing rider weight, % grade, and speed. These calculations are reduced to practice at analyticcycling.com and can be found in Bicycling Science 3rd Ed. (Wilson) MIT Press pp 136.
> 
> I have never heard anyone talk about metabolic power in relation to cycling, and in fact it only has meaning if you want to estimate calorie requirements as a function of wattage produced. While a number of calorie calculators use much lower numbers, a metabolic efficiency of 24% is typically assumed for a reasonably fit athlete.


I know all of this. My description of mechanical power is exactly what you just said. But people were talking about the physiological effects of losing weight and its effects on mechanical power so I was providing the distinction between mechanical and metabolic power. There is a reason no one talks about metabolic power's relation to cycling, because it has no effect on the speed of the bicycle.

I thought my wording was fairly clear.


----------



## woodys737 (Dec 31, 2005)

Xcelerate said:


> Added the bold. I think there is some confusion here concerning metabolic power (stored body energy converted into heat) vs mechanical power delivered to the cranks. In running, this is called ... (drumroll) ... running economy. * I don't know what it's called in cycling*.


Wattage.


----------



## Xcelerate (Mar 23, 2011)

woodys737 said:


> Wattage.


No, I was referring to the efficiency at which energy stored in the human body is converted to mechanical vs metabolic power.

Not a great overview, but see http://en.wikipedia.org/wiki/Running_economy


----------



## Xcelerate (Mar 23, 2011)

Drew Eckhardt said:


> They loose elsewhere because their power to drag ratio is worse than other body shapes.


I don't have any data to back this up, but I would think the aerodynamic differences between body size would be almost negligible compared to training...


----------



## redlude97 (Jun 29, 2010)

Terex said:


> *The bike/rider is a dynamic system. On average, if you add 5 lbs. of mass to a human, you add 2.5 lbs. of muscle. * On average, if you add 5 lbs. of mass to a bike, you add 5 lbs. of dead weight that must be moved dynamically in three dimensions. Forward movement is the major component of movement, but other components must be considered.
> 
> No, it's not appropriate to consider jumping curbs, but you must consider efforts needed to accelerate the bike and maintain speed. Did you observe Danilo De Luca climbing on the last big mountain stage of the Giro this year? The bike was all over the place. It takes energy to move the bike in such an oscillating, side-to-side motion in order to effect forward movement. The mass of the bike moved side-to-side. Danilo's mass was relatively still.
> 
> ...


Do you have a source for this?


----------



## Kerry Irons (Feb 25, 2002)

*Confusion*



Xcelerate said:


> Added the bold. I think there is some confusion here concerning metabolic power (stored body energy converted into heat) vs mechanical power delivered to the cranks. In running, this is called ... (drumroll) ... running economy. I don't know what it's called in cycling.


I think you are the only one who might be confused. When cyclists talk about power, they are referring EXCLUSIVELY to what is delivered, either to the cranks or the rear wheel depending on what power measuring device is employed. Absent a power measuring device, fairly accurate power estimates can be done with a simple calculation knowing rider weight, % grade, and speed. These calculations are reduced to practice at analyticcycling.com and can be found in Bicycling Science 3rd Ed. (Wilson) MIT Press pp 136.

I have never heard anyone talk about metabolic power in relation to cycling, and in fact it only has meaning if you want to estimate calorie requirements as a function of wattage produced. While a number of calorie calculators use much lower numbers, a metabolic efficiency of 24% is typically assumed for a reasonably fit athlete.


----------



## Terex (Jan 3, 2005)

Kerry Irons said:


> *Seldom does one get to see such a misrepresentation of the physics of cycling*. Either that or 1) you're joking, 2) this is a troll.
> 
> To the OP: except for a small difference in acceleration if the weight saved is totally in the wheels, there is zero difference between body weight and bike weight.


I agree. But WRT your post.


----------



## Kerry Irons (Feb 25, 2002)

pacificaslim said:


> BTW, I'm not trying to rationalize being overweight: I'm 6'0", 145 with under 10% body fat.
> 
> There is a lot more to riding a bike than power output. Unless you are talking about riding a bike attached to an indoor trainer. In the real world, we must "ride" the bike. That's why I always prefer to have a lighter bike to maneuver around and don't like this "total package" idea. Where the weight is matters - the closer it is to one's center of gravity (a beer belly for example) the less it takes to move, right? And conversely, weight further away from the core is like carrying weight on the end of a yardstick - takes much more force to lift/move, right?
> 
> This is much more obvious with mountain bikes and cyclocross as I mentioned before, but I believe it also holds for road cycling. Easy example: which is easier, bunnyhopping a bike over a storm drain when you have 30 lbs. in a backpack on your back (analogous to being overweight) or having that 30 lbs. in panniers on the bike?


While the OP was not specific in his definition of "performance" I think we can be pretty sure he was talking about speed, whether on the flats or when climbing. Not about how easily he can bunny hop or pop a wheelie. Your continuing references to irrelevant examples is entertaining, but it has nothing to do with whether a bike will go faster by reducing rider weight or bicycle weight.


----------



## Terex (Jan 3, 2005)

Kerry Irons said:


> While the OP was not specific in his definition of "performance" I think we can be pretty sure he was talking about speed, whether on the flats or when climbing. Not about how easily he can bunny hop or pop a wheelie. Your continuing references to irrelevant examples is entertaining, but it has nothing to do with whether a bike will go faster by reducing rider weight or bicycle weight.


The bike/rider is a dynamic system. On average, if you add 5 lbs. of mass to a human, you add 2.5 lbs. of muscle. On average, if you add 5 lbs. of mass to a bike, you add 5 lbs. of dead weight that must be moved dynamically in three dimensions. Forward movement is the major component of movement, but other components must be considered.

No, it's not appropriate to consider jumping curbs, but you must consider efforts needed to accelerate the bike and maintain speed. Did you observe Danilo De Luca climbing on the last big mountain stage of the Giro this year? The bike was all over the place. It takes energy to move the bike in such an oscillating, side-to-side motion in order to effect forward movement. The mass of the bike moved side-to-side. Danilo's mass was relatively still.

Forward movement predominates, but other movements are by no means insignificant. I'm sure any experienced cyclist would rather be a 5 pound larger cyclist, rather than add 5 pounds of bike weight.

In summary: 1) Bike coasting downhill from a dead stop - no difference. 2) Bike accelerating to speed on the flats - some advantage to human weight increase. 3) Bike climbing - bigger advantage to human weight increase.


----------



## Drew Eckhardt (Nov 11, 2009)

Kontact said:


> Power output varies by activity, in part due to something much like "muscle strength". Climbing specialists are rarely overall winners, for instance.


Although you can get better muscle recruitment standing, climbing specialists win in the mountains because ectomorphic bodies weighing about 2 pounds per inch (140 pounds for a 5'10" guy) tend to net higher power to weight ratios than other body types and that's what determines up-hill speed.

They loose elsewhere because their power to drag ratio is worse than other body shapes.


----------



## 55x11 (Apr 24, 2006)

jerrycan42 said:


> I know in my case, I'm 40 lbs overweight so I could stand to lose 25lbs, but my bike would disappear if it lost 25lbs...


not to be a smartass, but if you are 40 lbs overweight, you can stand to lose... 40 lbs!


----------



## 55x11 (Apr 24, 2006)

Kerry Irons said:


> Either that or 1) you're joking, 2) this is a troll.


I think it is 1) and 2) combined.


----------



## pacificaslim (Sep 10, 2008)

Kerry Irons said:


> While the OP was not specific in his definition of "performance" I think we can be pretty sure he was talking about speed, whether on the flats or when climbing. Not about how easily he can bunny hop or pop a wheelie. Your continuing references to irrelevant examples is entertaining, but it has nothing to do with whether a bike will go faster by reducing rider weight or bicycle weight.


If you just want an "in a vacuum" type "all objects fall at the same rate" type answer, then sure, it won't much matter where the weight is. But this is the real world and just like all objects not falling at the same rate in the physical world, where the weight is in a rider-bike combo is a distinction with a difference. Actually ride each combo around for a few hours in the real world and you will expend more energy riding the heavier bike than you will carrying the equivalent extra weight on your own body. After hours of this extra weight muscling around the heavier bike, the fatigue will impact the speed at which you are able to ride that bike. This is not "irrelevant".


----------



## redlude97 (Jun 29, 2010)

Terex said:


> Good point - that's why I looked it up before posting. Can't find what I was looking at, but quick check on Wiki re "Muscle" has 42% for voluntary muscle, and other amounts for additional mass for involuntary muscle and cardiac muscle. Looks to be close to 50% total.


While I don't totally agree/disagree with your initial post, I think the OPs question really was about losing 5lbs on the person versus losing 5lbs on the bike, and in that case, a 5lb loss in weight probably doesn't equate to a loss in 2.5lbs of muscle, so your conclusion may not be as obvious.


----------



## Terex (Jan 3, 2005)

redlude97 said:


> Do you have a source for this?


Good point - that's why I looked it up before posting. Can't find what I was looking at, but quick check on Wiki re "Muscle" has 42% for voluntary muscle, and other amounts for additional mass for involuntary muscle and cardiac muscle. Looks to be close to 50% total.


----------



## Kontact (Apr 1, 2011)

Xcelerate said:


> I don't have any data to back this up, but I would think the aerodynamic differences between body size would be almost negligible compared to training...


It isn't. Power to drag ratios are rather large and obvious between riders of different sizes.


----------



## Kerry Irons (Feb 25, 2002)

*Just not right*



pacificaslim said:


> If you just want an "in a vacuum" type "all objects fall at the same rate" type answer, then sure, it won't much matter where the weight is. But this is the real world and just like all objects not falling at the same rate in the physical world, where the weight is in a rider-bike combo is a distinction with a difference. Actually ride each combo around for a few hours in the real world and you will expend more energy riding the heavier bike than you will carrying the equivalent extra weight on your own body. After hours of this extra weight muscling around the heavier bike, the fatigue will impact the speed at which you are able to ride that bike. This is not "irrelevant".


As someone who came up when a super lightweight bike was considered to be 22 lbs and who now rides a bike that weighs about 17 lbs. I say "total bunk" on your claim about energy spent "muscling around" a bike that weighs 5 lbs. more. You're riding this thing down the road in a pretty much straight line - essentially the only energy spent is to move you and the bike in that straight line. If the total weight of you and the bike don't change, then moving 5 lbs. from you to the bike or the other direction will have insignificant effect on the energy expended. 

You can talk all you want about the fatigue of handling a bike, but for road riding, it simply doesn't apply.


----------



## Kerry Irons (Feb 25, 2002)

*Having data*



Xcelerate said:


> I don't have any data to back this up, but I would think the aerodynamic differences between body size would be almost negligible compared to training...


This is the difference between offering opinions and having data. Here is the data (hint: you're wrong):

From Bicycle Quarterly Volume 6, number 3. 
Wind tunnel tests at the U WA low speed tunnel:
standard racing position: 26.34 newtons drag
standard racing position, small rider: 20.31 newtons (23% reduction)


----------



## freighttraininguphill (Jun 7, 2011)

For me, losing flab off my body is what's helping the most. My Specialized Sirrus, which is basically a flat-bar road bike and is 2 pounds heavier than my drop bar road bike, climbs better than my Specialized Dolce road bike.

Before I gained all the weight I used to climb well on a heavy old Specialized Hardrock mtb.


----------



## Xcelerate (Mar 23, 2011)

Kerry Irons said:


> This is the difference between offering opinions and having data. Here is the data (hint: you're wrong):
> 
> From Bicycle Quarterly Volume 6, number 3.
> Wind tunnel tests at the U WA low speed tunnel:
> ...


Well I appreciate you providing the data, and I see that it does indeed make a difference, but I already said that my statement was a conjecture, so I think the re-emphasis on that was unnecessary. If you want points for "winning" here you go:

2 points


* I mean, it's kind of annoying. I say that I think something would be the case if I tested it, based on my knowledge of air resistance, but I admit the possibility that this is just an educated guess and needs data to back up it. Then you provide the data while going "haha you're wrong, what a loser". The data alone would be sufficient to make your point. Did you do this in your job as a chemical engineer, or only on this forum? Is this an attitude I need to learn to expect when I work in the industry?


----------



## PdxMark (Feb 3, 2004)

I keep expecting this thread to peter out.... Kerry's information is rock solid, as always. 

I'd add one very, very narrow circumstance in which I think weight on body has a different effect on riding than weight on bike -- high-geared standing climbing.. like on a fixed gear bike. During that specific time the rider's weight adds force to the pedals that helps with the climb, whereas weight on the bike would not be helping turn the pedals. But sit down and spin up the hill and that weight-on-body advantage is gone.


----------



## lookkg461 (Jun 9, 2011)

I've probably lost five lbs since spring when I started road biking again and I like to think that I've gained some muscle too. I'm definitely faster than I was before because of the training. It's hard to think that dropping 5lbs on my bike would make the same difference with no training.


----------



## PdxMark (Feb 3, 2004)

lookkg461 said:


> I've probably lost five lbs since spring when I started road biking again and I like to think that I've gained some muscle too. I'm definitely faster than I was before because of the training. It's hard to think that dropping 5lbs on my bike would make the same difference with no training.


You're adding extra variables to the question... fitness levels, extra muscle despite weight loss.. all the effects of training. That's different from the question at hand.


----------



## redlude97 (Jun 29, 2010)

lookkg461 said:


> I've probably lost five lbs since spring when I started road biking again and I like to think that I've gained some muscle too. I'm definitely faster than I was before because of the training. It's hard to think that dropping 5lbs on my bike would make the same difference with no training.


So the question you should ask yourself is this, do you think that you would be faster now on a bike 5lbs heavier or at the start of the season with your lighter bike?


----------



## woodys737 (Dec 31, 2005)

lookkg461 said:


> I've probably lost five lbs since spring when I started road biking again and I like to think that I've gained some muscle too. I'm definitely faster than I was before because of the training. It's hard to think that dropping 5lbs on my bike would make the same difference with no training.


Not the point though...

The problem is that you need to hold power constant to come up with any useful data. In other words, take the same "you" (trained or untrained) right now and compare the same "you" 5, 10, 15lbs heavier and look at the speed/time to climb up a hill. For this to work we have to assume the same conditions exist each run. Now do the same experiment with the same trained "you" and add 5, 10, 15lbs to the bike. Compare the speed/time to climb runs with a 5lbs heavier rider and a 5lbs heavier bike, 10lbs 15lbs etc...The answer, at least on analytic cycling is that a 5lbs heavier rider v a 5lbs heavier bike will reach the top of the climb at the same time.

Once you start to add variables such as different training technique (power output) aerodynamics, and even such things as PdxMark suggested standing v seated climbing, all the results get thrown out the window.


----------



## Allez Rouge (Jan 1, 1970)

PdxMark said:


> I keep expecting this thread to peter out.... Kerry's information is rock solid, as always.


So do I; and yes it is, as always.

For those who doubt what Kerry is saying, look at it this way: say that you have two full water bottles, each weighing 2.5 lbs each. Performance-wise -- which is what the OP asked -- do you really think it will make any difference whatsoever whether you put them in the cages on the bike, or stick them in your jersey pockets?


----------



## 55x11 (Apr 24, 2006)

freighttraininguphill said:


> For me, losing flab off my body is what's helping the most. My Specialized Sirrus, which is basically a flat-bar road bike and is 2 pounds heavier than my drop bar road bike, climbs better than my Specialized Dolce road bike.
> 
> Before I gained all the weight I used to climb well on a heavy old Specialized Hardrock mtb.


I am sorry but this thing about heavier bike climbing better is just mis-perception. Unless the heavy bike is more aero and you climb at 15mph (drop bar vs. flat bar - I doubt it), or you have some serious mechanical problem with your road bike. 

2lbs of exra weight are 2 lbs of extra weight.


----------



## The English Hacker (May 30, 2011)

So, my friend and I have similar bikes. I weigh 40lbs more than he does. He is also fitter than I. However, if I were to tell him that he had to wear a 40lb backpack I have a hard time imagining him keeping up with me.


----------



## freighttraininguphill (Jun 7, 2011)

55x11 said:


> I am sorry but this thing about heavier bike climbing better is just mis-perception. Unless the heavy bike is more aero and you climb at 15mph (drop bar vs. flat bar - I doubt it), or you have some serious mechanical problem with your road bike.
> 
> 2lbs of exra weight are 2 lbs of extra weight.


No mechanical problems with the road bike. The Sirrus does have wider bars though, so maybe it's something to do with position. I also like the gearing better on the Sirrus. It has a 38-tooth middle chainring, while the road bike has a 42. They're both triples, but I spend more time in the middle ring on steep climbs on the Sirrus than on the Dolce.


----------



## ziscwg (Apr 19, 2010)

seacoaster said:


> I asked my LBS if I would be further ahead to lose 5 lbs. or to spend $8,000 on a new bike that weighs 5 lbs. less than what I'm riding now. They told me to buy the new bike, so it must be better to ride a lighter bike than lose weight.


I hope this was sarcasm. The LBS wanted to sell yo a bike. That is why they are there. If you were at some kind of athlete training center, then I would maybe buy into that.


----------



## ziscwg (Apr 19, 2010)

getreal said:


> these threads crack me up.i know too many bozos out there looking for a 15 lb bike to climb freeway overpasses.



rotflmao,


----------



## Kerry Irons (Feb 25, 2002)

*Winning*



Xcelerate said:


> Well I appreciate you providing the data, and I see that it does indeed make a difference, but I already said that my statement was a conjecture, so I think the re-emphasis on that was unnecessary. If you want points for "winning" here you go:
> 
> 2 points
> 
> * I mean, it's kind of annoying. I say that I think something would be the case if I tested it, based on my knowledge of air resistance, but I admit the possibility that this is just an educated guess and needs data to back up it. Then you provide the data while going "haha you're wrong, what a loser". The data alone would be sufficient to make your point. Did you do this in your job as a chemical engineer, or only on this forum? Is this an attitude I need to learn to expect when I work in the industry?


No, it's not about winning. It's about you repeatedly offering conjecture based on incorrect assumptions and then getting tweaked about it when your assumptions are shown wrong. You could be asking questions about these things, but instead you're making incorrect observations. I'm sure it is annoying to be corrected this often, but as I said at the outset, this sort of thing has been going on for a decade here. That is definitely annoying to me. 

When you stand in front of two people, one 6' tall and the other 5'2", one weighing 180 lbs. and the other 100 lbs. and then you say you're making an educated guess that those two people have the same frontal area when on their bikes, it's a bit of a stretch (in my mind) to call that "an educated guess." 

And yes, when you get a bunch of chemical engineers in the room and one of them makes an obviously bogus assumption (rather than asking the others if they know the answer), the odds are good that the other engineers will point out the "obviously bogus assumption." 

I am reminded of a similarly LONG argument last year (two years ago?) with someone who had just taken a college physics class and was sure that because F = MA that someone riding up a hill at constant speed was actually accelerating. We went back and forth and back and forth - it took him a long time to realize that he really did not understand the simple physics. He could have asked for an explanation but instead insisted on trying to make his case and resisted the explanations offered.


----------



## Kerry Irons (Feb 25, 2002)

*Not quite*



The English Hacker said:


> So, my friend and I have similar bikes. I weigh 40lbs more than he does. He is also fitter than I. However, if I were to tell him that he had to wear a 40lb backpack I have a hard time imagining him keeping up with me.


If your friend is actually fitter, that would suggest he can put out more watts than you can. If you both weigh the same because you put 40lbs. of bricks in his backpack, he's still going to be faster because he puts out more power.


----------



## pacificaslim (Sep 10, 2008)

Allez Rouge said:


> So do I; and yes it is, as always.
> 
> For those who doubt what Kerry is saying, look at it this way: say that you have two full water bottles, each weighing 2.5 lbs each. Performance-wise -- which is what the OP asked -- do you really think it will make any difference whatsoever whether you put them in the cages on the bike, or stick them in your jersey pockets?


I don't think a 40 oz. water bottle would fit in either location but anyway, in that example, both sets of weight are close to the center of gravity or "core" of the rider/bike combo. But as weigh gets farther away, it takes more force to move.

So...How about if the question was jersey pockets vs. hanging off the front of your stem? Or jersey pocket vs. putting that water weight on your tires or rims? Over the course of a day in a real world where you start, stop, turn, dodge things, pick up the bike and move it around, etc.?

No one would argue this point when it comes to mountain biking. That most of you want to dismiss this point about leverage when discussing road bikes means you have a very boring picture of road cycling that doesn't really match reality, at least not in my neck of the woods.


----------



## Xcelerate (Mar 23, 2011)

Kerry Irons said:


> No, it's not about winning. It's about you repeatedly offering conjecture based on incorrect assumptions and then getting tweaked about it when your assumptions are shown wrong. You could be asking questions about these things, but instead you're making incorrect observations. I'm sure it is annoying to be corrected this often, but as I said at the outset, this sort of thing has been going on for a decade here. That is definitely annoying to me.
> 
> When you stand in front of two people, one 6' tall and the other 5'2", one weighing 180 lbs. and the other 100 lbs. and then you say you're making an educated guess that those two people have the same frontal area when on their bikes, it's a bit of a stretch (in my mind) to call that "an educated guess."
> 
> ...


How is this a LONG argument? I said I thought something, you provided the data, and I said okay you're right.



> When you stand in front of two people, one 6' tall and the other 5'2", one weighing 180 lbs. and the other 100 lbs. and then you say you're making an educated guess that those two people have the same frontal area when on their bikes, it's a bit of a stretch (in my mind) to call that "an educated guess."


I don't believe I had an "obviously bogus assumption". The projection of a cyclist's frontal area in a riding position onto a plane is not something that I imagined would differ by more than 50-100 square inches between riders, which in relation to the overall frontal (projected) area would seem small. That doesn't sound like an outlandish assumption to me.

You said it's a stretch in your mind. Well let's try something, if you want to. I know about 5 chemical engineers, and I'm sure you know plenty as well. Go ask your co-workers if they think that's a stretch, and I'll ask the ones I know. I won't lie. If they say they think it's a stretch, I'll let you know.

In all science, you make a hypothesis and then test it. My hypothesis was that the frontal projected area wouldn't differ much between cyclists. I never said "of course I'm right". I said I don't have data to back this claim up (almost no one on the internet says that), and I was hoping someone would provide some to either validate the claim or refute it. What I wasn't looking for was a refutation with an attitude.


EDIT:

1st reply - "I'm going to say that the air resistance will vary between riders but I don't necessarily think by a lot. Because if at two extremes you have a very fat person and a stick of a person riding, then yes it would, but for most of the average riders I would say it doesn't vary too much."


----------



## coby111 (Jun 10, 2011)

I'm getting into cycling and I've kinda been wondering this as well.


----------



## Kontact (Apr 1, 2011)

Kerry Irons said:


> This is the difference between offering opinions and having data. Here is the data (hint: you're wrong):
> 
> From Bicycle Quarterly Volume 6, number 3.
> Wind tunnel tests at the U WA low speed tunnel:
> ...


I'm not sure where you're going with this. The larger rider has more drag, but less drag per watt and is faster on flats because of this.

Xcelerate might be incorrect in his assumption, but if his assumption was a frontal area per output ratio, he was wrong for a reason that is different than what your post suggests. The larger rider is not equal, but faster, not slower.


----------



## Xcelerate (Mar 23, 2011)

Kontact said:


> I'm not sure where you're going with this. The larger rider has more drag, but less drag per watt and is faster on flats because of this.
> 
> Xcelerate might be incorrect in his assumption, but if his assumption was a frontal area per output ratio, he was wrong for a reason that is different than what your post suggests. The larger rider is not equal, but faster, not slower.


I have absolutely no problem being wrong. That's how you learn.

I do have a problem with getting verbally attacked: _This is the difference between offering opinions and having data. Here is the data (hint: you're wrong)_. And having my assumption called outlandish.


----------



## GDeAngelo (Aug 9, 2009)

Here is my input feel free to comment, I'm still new. But, on the road in general, I figure weight is weight. I'm sure you would be able to tell the difference, will it work in your favor I think it is arguable. Weight is weight, to a degree. I think it depends where the weight was loss when it comes to your body. If lost in overall body fat, then yes great. I think your performance would would increase. If lost in muscle, then where was the muscle lost? I mean 5lbs of muscle in the quads is enough to turn someone in to sprinter or not, imo. Now granted a 5 lb light bike, you would be less fatigued in most cases because of throwing/pushing a lighter bike. An extra 5lbs on your body, it is probably distributed throughout your body. Unless you are losing centralized weight. Your body is used to carrying that kind of weight, and has adapted. So, sure maybe 5lbs on the bike would make a difference. Now, in cross, bet your ass 5lbs in a bike would make a hell of a difference. You also have to take placebo into account. All in all, I would just lose 5lbs, lol. Cheaper and better for you, granted you aren't already in prime condition. 

All in all, I think 5lbs lost anywhere would be beneficial. I think you would notice lighter bike, but have similar results on being 5lbs lighter. With the exception of cross, I don't think the times at the end of day would be to far off.

Who knows, maybe I'm wrong, lol.


-Gianni


----------



## AJL (Jul 9, 2009)

On the simple question posed by the OP, Kerry Irons is *completely *correct.

I've noticed that people here, as Kerry mentions, are pointing out corner cases to justify their stances. With regard to the OPs question, these are irrelevant. Sorry, but it's true. 

We could, of course, spend time here spelling out the complete dynamics of a complex, inefficient bio-mechanical machine (a person) riding a bicycle under varying terrain and environmental factors. Further, we could examine the best riding positions for said person with respect to optimal efficiency, optimal performance, optimal recovery or any combination of the aforementioned. 

The problem is, there are a vast number of books and scientific papers dedicated to these very problems and we don't have the time or space in the forum to lay out the entire problem. Furthermore, since we don't fully understand the science (especially the human part) there are various possible solutions, which is why bike racing is part art, part science. We are getting better at it, but we have a long way to go.

If people want to understand more specific issue that are affect them, we have a Racing and Training forum that would be more helpful. You could search these forums for answers that have been given in the past. If you are really, really interested in this subject. I'd suggest that most posters would be better off educating themselves via books and online papers/presentations.


----------



## redlude97 (Jun 29, 2010)

pacificaslim said:


> I don't think a 40 oz. water bottle would fit in either location but anyway, in that example, *both sets of weight are close to the center of gravity or "core" *of the rider/bike combo. But as weigh gets farther away, it takes more force to move.
> 
> So...How about if the question was jersey pockets vs. hanging off the front of your stem? Or jersey pocket vs. putting that water weight on your tires or rims? Over the course of a day in a real world where you start, stop, turn, dodge things, pick up the bike and move it around, etc.?


Thats the whole point, any reasonable loss in weight on a person or a bike will be distributed throughout so the difference noticed will be minimal for either case. 



pacificaslim said:


> So...How about if the question was jersey pockets vs. hanging off the front of your stem? Or jersey pocket vs. putting that water weight on your tires or rims? Over the course of a day in a real world where you start, stop, turn, dodge things, pick up the bike and move it around, etc.?


What if the choice was between the weight strapped to your helmet or on your rims? Would that change your answer? It still doesn't prove anything.


----------



## woodys737 (Dec 31, 2005)

AJL said:


> On the simple question posed by the OP, Kerry Irons is *completely *correct.
> 
> I've noticed that people here, as Kerry mentions, are pointing out corner cases to justify their stances. With regard to the OPs question, these are irrelevant. Sorry, but it's true.
> 
> ...


+1. I forgot I had THIS CYCLING CALCULATOR in my favorites. You can input the weight of the two riders and their bikes and it will calculate speed based on power, grade and environmental conditions. Looks to me like pound for pound a reduction in bodyweight and bike weight equals the same performance.


----------



## Terex (Jan 3, 2005)

woodys737 said:


> +1. I forgot I had THIS CYCLING CALCULATOR in my favorites. You can input the weight of the two riders and their bikes and it will calculate speed based on power, grade and environmental conditions. Looks to me like pound for pound a reduction in bodyweight and bike weight equals the same performance.


This provides a good estimate based on the limited parameters of the mathematical model being used.


----------



## sweeners (Jul 23, 2008)

*Wrong*



Kerry Irons said:


> It's not about muscle strength, it's about power output. If both riders have the same power output, they will go the same speed up the hill. If you can demonstrate otherwise, you will replace Isaac Newton in the physics hall of fame.



See the bike calculator for some useful examples - keep all variables the same except rider weight. Give rider B an extra 5lbs. The lighter cyclist goes faster by 0.3333%. Lets assume this is a drag co-efficient somewhere in the calcs.

Now move from 0% gradient to 7% gradient - The lighter cyclist now goes faster by 2.725%. Why the increase in fasterness (that's my word)? Because to counteract the effect of gravity whilst climbing requires power. The more mass you are trying to push against gravity, the more power you need to go at the same speed. If you use the same power, you'll go slower. 

Consider a marble and a bowling ball on a slope. Which is easier to keep from rolling down the slope? Why?

Once you account for that extra power requirement you're back onto the calcs for a flat road where weight doesn't matter much, but the different inital power requirements to overcome gravity remain as a starting point.


----------



## woodys737 (Dec 31, 2005)

Sweeners,

You took KI's post out of context. You are saying the same thing, but you must read the post that started this mini thread from pacificaslim:



pacificaslim said:


> For those who would rather have a lighter rider and heavier bike and believe in the "total package weight" theory of performance: how far are you willing to take that? Would you expect similar riding experience for a 120 lb. rider on an 95 lb. bicycle as a 200 lb. rider on 15 lb. bicycle? If not, at what weight levels does your "lighter rider/heavier bike" preference break down? And why, if it breaks down at some point, do you still hold your original thesis of "total package" and prefer lighter rider than lighter bike?
> 
> (and btw, forget about the muscle difference between the 200 lb. and 120 lb. rider: other threads have argued pretty convincingly, and pro tour cyclists are good evidence as well, that it does not take much muscle or strength at all to ride a bicycle).


To which KI responded:



Kerry Irons said:


> It's not about muscle strength, it's about power output. If both riders have the same power output, they will go the same speed up the hill. If you can demonstrate otherwise, you will replace Isaac Newton in the physics hall of fame.


To which you responded:



sweeners said:


> See the bike calculator for some useful examples - keep all variables the same except rider weight. Give rider B an extra 5lbs. The lighter cyclist goes faster by 0.3333%. Lets assume this is a drag co-efficient somewhere in the calcs.
> 
> Now move from 0% gradient to 7% gradient - The lighter cyclist now goes faster by 2.725%. Why the increase in fasterness (that's my word)? Because to counteract the effect of gravity whilst climbing requires power. The more mass you are trying to push against gravity, the more power you need to go at the same speed. If you use the same power, you'll go slower.
> 
> ...


That is, two riders that have the same total weight (rider/bike) if generating the same power will achieve the same speed (assuming other variables like aerodynamics are equal).


----------



## sweeners (Jul 23, 2008)

Oh yeah, sorry Kerry!: blush2:


----------



## Kontact (Apr 1, 2011)

I'm still uncertain why everyone thinks taking a healthy athletic rider and removing 5 pounds of muscle and blood would be the same as subtracting 5 pounds of inert structural material. That flesh does work, and the more there is, the more work it does.


----------



## redlude97 (Jun 29, 2010)

Kontact said:


> I'm still uncertain why everyone thinks taking a healthy athletic rider and removing 5 pounds of muscle and blood would be the same as subtracting 5 pounds of inert structural material. That flesh does work, and the more there is, the more work it does.


95% of "healthy riders" could stand to lose 5lbs in BF. If it is fat it probably a net loss in work input, and assuming the rider is losing that weight through biking, they will probably end up stronger after the 5lbs of loss than before, irregardless of the % of fat compared to muscle lost, but that doesn't seem to be the point of comparison. If we wanted to keep things simple, assume the rider lost the 5lbs through liposuction(probably the same cost as shaving 5lbs off the bike). Would the conclusion still be the same?


----------



## jerrycan42 (Aug 18, 2010)

Kontact said:


> I'm still uncertain why everyone thinks taking a healthy athletic rider and removing 5 pounds of muscle and blood would be the same as subtracting 5 pounds of inert structural material. That flesh does work, and the more there is, the more work it does.


Muscle - no 
Fat - yes


----------



## Kontact (Apr 1, 2011)

redlude97 said:


> 95% of "healthy riders" could stand to lose 5lbs in BF. If it is fat it probably a net loss in work input, and assuming the rider is losing that weight through biking, they will probably end up stronger after the 5lbs of loss than before, irregardless of the % of fat compared to muscle lost, but that doesn't seem to be the point of comparison. If we wanted to keep things simple, assume the rider lost the 5lbs through liposuction(probably the same cost as shaving 5lbs off the bike). Would the conclusion still be the same?


Fat is just as inert as aluminum, so it is a valid comparison. But if this thread is about performance, and not duffers pedaling the countryside on their Rivendells, I think it is fair to assume that there isn't much fat left.

When I weigh 150, I know I have 5 lbs. of winter fat. When I weight 145, I know that I'm between 7 and 9% bodyfat. When I dip into the 130s, it is because something bad is happening and my forearms and calves are smaller from a reduction in muscle mass. Muscle mass that delivers more power to the pedals than is a detriment during the ride, because of the volume vs. area curves.

Pro cyclists lose muscle mass in the long races - and it doesn't really help them. When very fit people are burning thousands of calories a day from just riding, the muscle thins too - especially if you let it.

So if the question was specific to a racer and a racer's bike, I don't think it is such a simple answer. For every rider there is probably an ideal body composition/weight, and going below it hurts overall performance, even if it boosts climbing speeds. And when you do the math, you find that climbing performance is maybe a 1/3 of overall speed - giving up the ability to fight the wind on flats will cost you.


Before anyone accuses me of using extreme examples, I really think talking about fat cyclist performance is pretty absurd. If we are really talking about performance, then we need to talk about people who really perform. Not people with guts, or riding in sandals, or on hybrids. Lean athletes who log real mileage and have aerodynamic postions should be the starting point for any discussion of this kind.


----------



## redlude97 (Jun 29, 2010)

Kontact said:


> Fat is just as inert as aluminum, so it is a valid comparison. But if this thread is about performance, and not duffers pedaling the countryside on their Rivendells, I think it is fair to assume that there isn't much fat left.
> 
> When I way 150, I know I have 5 lbs. of winter fat. When I way 145, I know that I'm between 7 and 9% bodyfat. When I dip into the 130s, it is because something bad is happening and my forearms and calves are smaller from a reduction in muscle mass. Muscle mass that delivers more power to the pedals than is a detriment during the ride, because of the volume vs. area curves.
> 
> ...


First, I think you have a very skewed view of the "average healthy rider". I don't think we are talking about elite pro racers as the "average". I would bet that less than 5% of road cyclists have less than 10% BF. So for the majority of "healthy riders" that aren't overweight in the 10-20% range could easily lose 5lbs of mostly fat and not much muscle.

If you want to continue to use the elite racer body type as the basis, then I would argue that it would be nearly impossible to shave 5lbs off of the average racer's bike without some serious compromises, so then the options dwindle to losing weight off the body as the main source of weight savings if that is what is desired.


----------



## terzo rene (Mar 23, 2002)

Kontact said:


> Fat is just as inert as aluminum


 Hardly. It's closer to aluminum than it is to muscle, but not at all inert. It takes oxygen and fuel to keep a fat cell alive, and they produce dozens of compounds in a varying cocktail that, among other things, can alter the propensity to gain other fat cells. Although it makes only a very small difference in power to the road they do come with more cost than just their weight.


A partial list of activities of those lazy fat cells
https://img.medscape.com/fullsize/migrated/528/575/ce528575.tab1.gif


----------



## Kontact (Apr 1, 2011)

redlude97 said:


> First, I think you have a very skewed view of the "average healthy rider". I don't think we are talking about elite pro racers as the "average". I would bet that less than 5% of road cyclists have less than 10% BF. So for the majority of "healthy riders" that aren't overweight in the 10-20% range could easily lose 5lbs of mostly fat and not much muscle.
> 
> If you want to continue to use the elite racer body type as the basis, then I would argue that it would be nearly impossible to shave 5lbs off of the average racer's bike without some serious compromises, so then the options dwindle to losing weight off the body as the main source of weight savings if that is what is desired.


I'm sure it is much less than 5%! But there really isn't much point in talking about fractional performance gains for commuters and tourists.

I propose that any conversation about aerodynamics, gram counting, performance supplements and rolling resistance be aimed at something like a moderately successful CAT 2 or 3 racer, or the equivalent. Not pros, not charity riders, but people who could conceiveably receive some benefit from single digit gains.

Otherwise, the signal to noise ratio just makes the whole conversation pointless. You don't consider ceramic bearings to improve your ride times if your stomach keeps getting in the way of your pedaling. That doesn't make any sense as a conversation, so use such a ridiculous situation as a baseline assumption?


Terzo,

No argument. I just meant that fat doesn't do anything to propel a rider any more than a rock does. But I agree 100% that fat is more than just a weight, it's decreased fitness in every sense - it doesn't matter what your lung capacity is if your arteries are clogged.


----------



## Terex (Jan 3, 2005)

Kontact said:


> I'm still uncertain why everyone thinks taking a healthy athletic rider and removing 5 pounds of muscle and blood would be the same as subtracting 5 pounds of inert structural material. That flesh does work, and the more there is, the more work it does.


Not everyone. Until the bike starts pedaling itself, that is.


----------

