# Wheel balancing?



## Mr. IROC-Z (Mar 20, 2007)

Hi guys,
I have several road bikes that I wrench on. I have recently noticed that when I have a bike in my work stand (suspended from the seat post) and I spin the rear tire really fast via the cranks, it will make the entire frame shake. It almost looks like an 'up and down' motion. The wheels does not appear to be out of true. I have noticed this will happen with cheaper rims. I did the same thing with the Fulcrum Zeros, and there is absolutely no frame movement.
Can anyone explain to me why this happens? When I ride the wheels with the shaking, I cannot feel the 'up and down' movement.
Any advice would be appreciated.


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## MisterMike (Aug 12, 2004)

Cheaper rims extrusions may be less consistent over length than more expensive ones but I would guess the major contributor to the out of balance we all see with bike rims is due to variances in the tire. I've always noticed the shake you describe in a stand. Some summers more than others as tires are different each year. Never feel it in on the road.

Absolutely no frame movement is very odd actually, especially if there is a tire on the rim.

Advice - barring any visible bulges or other defects with the tire, go ride and don't worry about it unless you feel it.


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## Mike T. (Feb 3, 2004)

It's normal for some wheels, it's been noted by many people over the years and it's really a non-issue. Nothing will be noticed and no harm will result.

I remember a famous wheelbuilder in the UK years ago who used to balance his wheels. I think it was more of a sales gimmick than an improvement. On my front wheels I do out my computer magnet at the light side of the wheel though.


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## old_fuji (Mar 16, 2009)

does it have a reflector on it?


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## RHankey (Sep 7, 2007)

Add a couple more spokey dockey's and call it a day.


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## Kerry Irons (Feb 25, 2002)

*Understanding the physics*



Mr. IROC-Z said:


> I have recently noticed that when I have a bike in my work stand (suspended from the seat post) and I spin the rear tire really fast via the cranks, it will make the entire frame shake. Can anyone explain to me why this happens? When I ride the wheels with the shaking, I cannot feel the 'up and down' movement.


The motion is from the wheel/tire being out of balance, and is normal. Most wheels with a tire mounted would do this. However, when you are on the road this does not occur. The tire is in constant contact with the road, and so cannot develop any motion due to being out of balance. In a car, with a suspension system, an out of balance tire can activate the suspension - car tires have to be balanced. On a bicycle, there is hugely less mass than with a car tire, and there is no suspension to activate. Absolutely NOT an issue.


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## kbiker3111 (Nov 7, 2006)

I think Fulcrum advertises their wheels as perfectly balanced and counterbalanced for the tube valve. Other wheels are not, but I don't think it matters.


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## twinkles (Apr 23, 2007)

The rim is heavier at the seam where the rim is welded. Spin a wheel and it will settle with the weld at the bottom. I use long stem tubes to balance out the wheel, and cause I got a good deal on some long stem ultra light tubes. I don't think it's anything to worry about, unless you're hitting 80 mph, while riding no handed.


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## zoikz (Sep 5, 2003)

Check the round.


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## bradleyp (Sep 5, 2006)

Most wheels are not counter-balanced. As they spin down, they will settle with the heaviest side down. What you are seeing when you wind them up on a repair stand is indeed the fact that they are out of balance. I doubt it makes any real difference while riding. Maybe noticeable during really, really fast descents.

I own/have owned several pair of Zipps, American Classic, Mavic, and other nice wheels. The only wheels that I have ever had that are perfectly balanced are some Hed Ardennes. I'm pretty sure all Heds get balanced before they ship. Sounds like Fulcrum does this too...


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## den bakker (Nov 13, 2004)

twinkles said:


> The rim is heavier at the seam where the rim is welded. Spin a wheel and it will settle with the weld at the bottom. I use long stem tubes to balance out the wheel, and cause I got a good deal on some long stem ultra light tubes. I don't think it's anything to worry about, unless you're hitting 80 mph, while riding no handed.


so how does the added weight affect acceleration? Now that we discuss non-issues


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## mtpisgah (Jan 28, 2004)

My Zipp 303 tubulars were not balanced and it drove me crazy. It was never a safety or power issue for me, it was just irritating.


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## Kerry Irons (Feb 25, 2002)

*How could you tell?*



mtpisgah said:


> My Zipp 303 tubulars were not balanced and it drove me crazy. It was never a safety or power issue for me, it was just irritating.


What drove you crazy? Out of round or out of true wheels would transmit vibration to the rider, as would tires that were lumpy. But out of balance wheels would not transmit vibration unless they were so out of balance that the forces generated could significantly deform the sidewalls of the tires with each revolution. Not likely. Not likely at all.


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## twinkles (Apr 23, 2007)

I build my own wheels and they are as round as a wheel can possibly be. Every wheel I've ever seen settles at the weld after being spun.


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## twinkles (Apr 23, 2007)

I dont think a person can tell the slight inbalance caused by the weld while riding. And if it were noticeable, it would be felt at high speed more than acceleration. I've recently built a sub 1500 g wheelset, and have noticed how quickly they accelerate, but also noticed how quickly I lose flywheel effect compared to my old wheels. Nothing is perfect in this world.


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## bwhite_4 (Aug 29, 2006)

Any manufacturer who "balances" wheels do it for the marketing. Valve stems differ in length and can shift the heavy side of the wheel.

Either way, it doesn't really matter.


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## mtpisgah (Jan 28, 2004)

Kerry Irons said:


> What drove you crazy?


When I frist put the wheels on the bike, I rode on a flat road cruising about 24mph. Being new to tubulars at the time, I thought it was the tires. When the back tire was worn out, I put the bike on the stand without the back tire, turned the cranks hard, and could feel the surge in the wheel from it being out of balance. I put wheel magnets on it and balanced it. It looked stupid that way so I rode the wheels three years with them surging.


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## monocognizant (Sep 12, 2008)

Mr. IROC-Z said:


> Hi guys,
> I have several road bikes that I wrench on. I have recently noticed that when I have a bike in my work stand (suspended from the seat post) and I spin the rear tire really fast via the cranks, it will make the entire frame shake. It almost looks like an 'up and down' motion. The wheels does not appear to be out of true. I have noticed this will happen with cheaper rims. I did the same thing with the Fulcrum Zeros, and there is absolutely no frame movement.
> Can anyone explain to me why this happens? When I ride the wheels with the shaking, I cannot feel the 'up and down' movement.
> Any advice would be appreciated.


It's out of balance because of the weight of the valve stem. Take your tire and tube off and spin it.


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## Kerry Irons (Feb 25, 2002)

*Not likely true*



monocognizant said:


> It's out of balance because of the weight of the valve stem. Take your tire and tube off and spin it.


This is unlikely. Typically, the rim joint outweighs the valve stem. In most wheels, the wheel will be MORE out of balance without the tire/tube in place.


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## Kerry Irons (Feb 25, 2002)

*Still not clear*



mtpisgah said:


> When I frist put the wheels on the bike, I rode on a flat road cruising about 24mph. Being new to tubulars at the time, I thought it was the tires. When the back tire was worn out, I put the bike on the stand without the back tire, turned the cranks hard, and could feel the surge in the wheel from it being out of balance. I put wheel magnets on it and balanced it. It looked stupid that way so I rode the wheels three years with them surging.


I guess I'm not hearing what you experienced. You don't say that the wheels were round and true, and you don't say that the ride improved once you "balanced" the wheels with the magnets. Nearly every wheel ever built will cause the frame to shake if you crank it up to high speed in a workstand. You do not feel that on the road. You might feel other things, but not wheel balance.


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## mtpisgah (Jan 28, 2004)

Kerry Irons said:


> Nearly every wheel ever built will cause the frame to shake if you crank it up to high speed in a workstand. You do not feel that on the road. You might feel other things, but not wheel balance.


It feels like it surges when riding. On the stand you could tell it even more. None of my other wheels do it on the stand or more importantly, on the road. I figured it was because the tubular rim was so light that any little imbalance would make it surge. When I bought my Edge carbon clinchers I checked them and they don't do it. 

The wheel was round, the tire was round with no apparent bulges. I don't know what caused it to feel the way it did and it doesn't matter anymore because I sold them about three months ago. The surging is not why I sold them, I just decided I didn't like dealing with tubulars. I also didn't like the way they cornered. A friend told me the cornering was due to using Conti 4000gp's and that may be to some extent.


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## Nielly (Sep 21, 2009)

I would suspect the tire more than anything to do with the rim. Did you always run conti tubulars? Did you ever try running a different tire?


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## shaochieh (Apr 19, 2002)

I have a set of 7801 Tubular and they are counter balanced as part of the wheel's design. The problem I encounter is the way tubular tires roll. I love them dearly but the never roll the best my me. I don't believe anyone can glue a tubular tire as round as a clincher tire. I sometimes rather have my clincher because they are perfect round than using my tubular on high speed downhills. I even try use tape one time to make sure the tire is on my rim perfect round and align but no joy. The Conti-GP 4000 tires is not perfectly round.  So I don't worry about it anymore as long my tire don't roll off.


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## Nielly (Sep 21, 2009)

shaochieh said:


> I have a set of 7801 Tubular and they are counter balanced as part of the wheel's design. The problem I encounter is the way tubular tires roll. I love them dearly but the never roll the best my me. I don't believe anyone can glue a tubular tire as round as a clincher tire. I sometimes rather have my clincher because they are perfect round than using my tubular on high speed downhills. I even try use tape one time to make sure the tire is on my rim perfect round and align but no joy. The Conti-GP 4000 tires is not perfectly round. So I don't worry about it anymore as long my tire don't roll off.


Well I dont know if it would be the glue job causing it. You would really have to mess it up to get the tire to be out of round much. I have found that there is quite a variation among tubular tires with regard to the seem. Due to the way tubulars are made there is always a seem where they overlap each end of the casing during construction. How welll this is done is the key and one of the things that distinguishes a good tire from an ok tire. I always found Vittoria CX's to be great in this regard, the challenge criterium I am running right now are very good. You should try different brands and models of tires. I'm sure you could find one that you would be happy with. I stopped using conti's a while ago but don't recall if it was due to that or something else about the way they rode I didn't like.


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## valleycyclist (Nov 1, 2009)

You can get a rim that has a balance weight around the valve stem to offset the additional weight of the rim joint. Take a look at the Torelli Triumph or Ambrosio Excellence rims. I notice that lots of pros use balanced rims in the Spring classics.

https://s975.photobucket.com/albums/ae237/pweiss/Torelli%20Triumph%20Campy%20Record/

https://s975.photobucket.com/albums/ae237/pweiss/Torelli%20Triumph%20White%20Industries%20Silver/

------------------------------------
https://www.valleycyclist.com


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## been200mph (May 28, 2004)

Kerry Irons said:


> The motion is from the wheel/tire being out of balance, and is normal. Most wheels with a tire mounted would do this. However, when you are on the road this does not occur. The tire is in constant contact with the road, and so cannot develop any motion due to being out of balance. In a car, with a suspension system, an out of balance tire can activate the suspension - car tires have to be balanced. On a bicycle, there is hugely less mass than with a car tire, and there is no suspension to activate. Absolutely NOT an issue.


Found this old but interesting thread. I disagree with this statement; be there suspension or not an imbalance is transmitted to the car or bike. Suspension may absorb a bit of it but it's still transmitted. Case in point is my dragster which has no suspension. An imbalanced wheel/tire will shake the living beegeezus out of you. And actually I do add nuts to the Presta stems on the road bike to help balance things out. When you can spin a wheel/tire and feel it shake back and forth you know it's out of balance. Between magnet placement and nuts on the stem it takes the shake out of them easily. It'd be interesting to see what rpm/speed these imbalances are at their peak. I'd believe it will vary a bit wheel to wheel. Anyhow... it's one of those can't-hurt things IMO.


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## RC28 (May 9, 2002)

been200mph said:


> Found this old but interesting thread. I disagree with this statement; be there suspension or not an imbalance is transmitted to the car or bike. Suspension may absorb a bit of it but it's still transmitted. Case in point is my dragster which has no suspension. An imbalanced wheel/tire will shake the living beegeezus out of you. And actually I do add nuts to the Presta stems on the road bike to help balance things out. When you can spin a wheel/tire and feel it shake back and forth you know it's out of balance. Between magnet placement and nuts on the stem it takes the shake out of them easily. It'd be interesting to see what rpm/speed these imbalances are at their peak. I'd believe it will vary a bit wheel to wheel. Anyhow... it's one of those can't-hurt things IMO.


Yes, I agree that it can be felt.My carbon wheels exhibited the imbalance. My aluminum ones did not, simply because, as Kerry explained, the joint in the rim (which is the heavy point of the wheel) is mostly counterbalanced by the presta valve opposite it. However, in carbon wheels, since there is no welded joint, the valve doesn't have anything to use as a counterbalance. Some wheels are worse than others in this aspect. Some of this inbalance can be countered to a point , in the front wheel, by placing the computer magnet opposite the valve. What I ended up doing in my Corima Aeros was to place several short strips of lead tape (the type that is used by tennis players on their racquets) on top of each other, on both sides of the rim opposite the valve. It doesn't look too bad...just a 4" x 1/4" gray strip on the carbon. Works like a charm. And yes, when the wheels were not balanced, the bike shaked violently in the stand. On the road when doing 45+ kph it made you aware that the issue was there. Kind of like a flat or high spot on the tire, a continuous pulsation that you could feel from the saddle. Not an issue at all at lower speeds or when climbing. I don't have the wheels here with me but can take a picture of my fix and post it later.


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## Kerry Irons (Feb 25, 2002)

*Tire flex*



been200mph said:


> Found this old but interesting thread. I disagree with this statement; be there suspension or not an imbalance is transmitted to the car or bike. Suspension may absorb a bit of it but it's still transmitted. Case in point is my dragster which has no suspension. An imbalanced wheel/tire will shake the living beegeezus out of you.


This is because you are running MUCH lower pressure in the dragster tires and so the tire itself can deform significantly due to the imbalance forces. Not so on a bicycle tire - the forces are much smaller and the tire is pneumatically much stiffer.


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## been200mph (May 28, 2004)

Kerry Irons said:


> This is because you are running MUCH lower pressure in the dragster tires and so the tire itself can deform significantly due to the imbalance forces. Not so on a bicycle tire - the forces are much smaller and the tire is pneumatically much stiffer.


Wrong. If the front tires are not balanced it'll shake the steering wheel out of your hands. They're not anywhere near the roughly 5-6 psi the rear tires are; they're much higher. It's a fact... bike tires/wheels can also be out of balance. And it's most often reasonably easy to correct that.


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## Kerry Irons (Feb 25, 2002)

*Something else*



RC28 said:


> Yes, I agree that it can be felt.My carbon wheels exhibited the imbalance.


Given the light weight of a CF wheel, it's very hard to imagine that the weight of a valve stem could possibly result in anyting you could feel. I don't doubt you felt something, but I've had wheels with SIGNIFICANTLY more weight imbalance than a valve stem would cause and there was zero effect that you could feel, regardless of speed. In order for you to feel something due to imbalance, the tire would actually have to deflect enough so that you could feel an "up and down" motion. At 90+ psi, it ain't gonna happen. Just saying.


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## been200mph (May 28, 2004)

Kerry Irons said:
 

> Given the light weight of a CF wheel, it's very hard to imagine that the weight of a valve stem could possibly result in anyting you could feel. I don't doubt you felt something, but I've had wheels with SIGNIFICANTLY more weight imbalance than a valve stem would cause and there was zero effect that you could feel, regardless of speed. In order for you to feel something due to imbalance, the tire would actually have to deflect enough so that you could feel an "up and down" motion. At 90+ psi, it ain't gonna happen. Just saying.


An imbalance is an imbalance. Pressure is irregardless.


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## RC28 (May 9, 2002)

Kerry Irons said:


> Given the light weight of a CF wheel, *it's very hard to imagine that the weight of a valve stem could possibly result in anyting you could feel*. I don't doubt you felt something, but I've had wheels with SIGNIFICANTLY more weight imbalance than a valve stem would cause and there was zero effect that you could feel, regardless of speed. In order for you to feel something due to imbalance, the tire would actually have to deflect enough so that you could feel an "up and down" motion. At 90+ psi, it ain't gonna happen. Just saying.


You are correct about that .It's about 10 g...which is very small compared to the weight of the wheel (about 1.5-2%) so it SHOULDN'T be that big of a deal. In MY experience , however, it DOES make a difference. If you lived nearby I would be more than glad to loan them to you so that you could check them out yourself.

Some of my teammates had commented that they had similar issues on their carbon wheels ( another set of Corimas, a set of 303s and some 404s and some Gigantex based wheels). They followed my example and ALL reported that the wheels behaved much better.

Just saying...


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## Kerry Irons (Feb 25, 2002)

*Jus wrong*



been200mph said:


> An imbalance is an imbalance. Pressure is irregardless.


You cannot feel an up and down motion due to imbalance unless the wheel or the tire is deforming. Simple as that. A high pressure road bike tire is very stiff pneumatically and will not significantly deform due to the mass of a valve stem. Analogies to car tires are meaningless because they are so much more deformable and the forces of imbance are so much larger.


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## been200mph (May 28, 2004)

Kerry Irons said:


> You cannot feel an up and down motion due to imbalance unless the wheel or the tire is deforming. Simple as that. A high pressure road bike tire is very stiff pneumatically and will not significantly deform due to the mass of a valve stem. Analogies to car tires are meaningless because they are so much more deformable and the forces of imbance are so much larger.


I give up. Tire deformations or not if there is an imbalance it is there and can be felt. My last post since we obviously have differing thoughts and likely won't change each other's opinion, lol. My only suggestion is to do some research into vibrations and the hows and whys of them. I've raced some reasonably fast stuff and am pretty analytical due to wanting to come home to my family after a day at the races. I've carried that over to biking in terms of trying to make each and every part (I can afford, lol) work to it's best. In short... anything that rotates will benefit from being balanced. Be it on or in a car, or a bike.


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## Quixote (Aug 26, 2008)

KerryIrons, ever ridden Zipp 1080s without something like fishing weights to counter balance the extremely long valve stems? "Yikes", is all I can say. Tire preassure won't do anything for those wheels.


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## tone12 (Feb 4, 2007)

All of my tubulars are unbalanced. Not one of them is noticeable while riding or racing, even at speed. In fact, I've hit high 50's going down a long hill while in a race and not once did I notice or feel a surging or unbalanced sensation.


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## rruff (Feb 28, 2006)

Quixote said:


> KerryIrons, ever ridden Zipp 1080s without something like fishing weights to counter balance the extremely long valve stems? "Yikes", is all I can say. Tire preassure won't do anything for those wheels.


I ride the 82mm model on the front, and exceed 40mph every week in our local TT... and wheel balance is not on my list of worries. A few grams of imbalance is tiny compared to the whole system.


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## orangeclymer (Aug 18, 2009)

I'll take balanced over unbalanced any day........and while the diff may be minor it does effect the ride.:thumbsup:


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## Kerry Irons (Feb 25, 2002)

*A little history*



been200mph said:


> I give up. Tire deformations or not if there is an imbalance it is there and can be felt. My last post since we obviously have differing thoughts and likely won't change each other's opinion, lol. My only suggestion is to do some research into vibrations and the hows and whys of them. I've raced some reasonably fast stuff and am pretty analytical due to wanting to come home to my family after a day at the races. I've carried that over to biking in terms of trying to make each and every part (I can afford, lol) work to it's best. In short... anything that rotates will benefit from being balanced. Be it on or in a car, or a bike.


Here's the deal. This issue has been discussed TO DEATH over at least the 40 years that I've been involved in cycling. Mostly, it is someone from motorcycling or auto racing who relates how important wheel balancing is, but it NEVER has been identified as an issue for a round and true bicycle wheel. Full stop. If you are sensing vibrations it is from an out of round wheel (rim or tire) or out of true wheel, not from an out of balance wheel.

I've hit 60 mph on downhills with "out of balance" wheels (many different wheels over many years) and never felt a single bit of vibration due to the balance issue. You can put these bikes in a workstand, crank them up to speed, and the stand will be jiggling significantly from the out of balance wheel. But when you put them on the road, the force of that out of balance wheel would have to flex the tire sidewall enough so that you could feel it. The rotating kinetic energy of a few grams simply will not counteract the weight of the rider enough to flex the sidewall of the tire. It's really that simple.

It's a totally different situation for auto and motorcycle tires and wheels both in terms of the masses invovled and the flex of the tire sidewalls.


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## been200mph (May 28, 2004)

Kerry Irons said:


> Here's the deal. This issue has been discussed TO DEATH over at least the 40 years that I've been involved in cycling. Mostly, it is someone from motorcycling or auto racing who relates how important wheel balancing is, but it NEVER has been identified as an issue for a round and true bicycle wheel. Full stop. If you are sensing vibrations it is from an out of round wheel (rim or tire) or out of true wheel, not from an out of balance wheel.
> 
> I've hit 60 mph on downhills with "out of balance" wheels (many different wheels over many years) and never felt a single bit of vibration due to the balance issue. You can put these bikes in a workstand, crank them up to speed, and the stand will be jiggling significantly from the out of balance wheel. But when you put them on the road, the force of that out of balance wheel would have to flex the tire sidewall enough so that you could feel it. The rotating kinetic energy of a few grams simply will not counteract the weight of the rider enough to flex the sidewall of the tire. It's really that simple.
> 
> It's a totally different situation for auto and motorcycle tires and wheels both in terms of the masses invovled and the flex of the tire sidewalls.


Lol. I highly suggest you research the physics of balancing and imbalance issues. Any rotating part will benefit from being balanced; bar none. If you're that confident that a more solid object doesn't need to be balanced then let me know the next time you fly and I'll see if the A&P techs can remove one rotor blade from the compressor of an engine. After all, it's a solid mass so it can't cause an issue, right? Seriously... with some mechanical research you'll understand the varying orders of vibration and what is done to control them. End of rant.


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## Kerry Irons (Feb 25, 2002)

*The significance of zilch*



been200mph said:


> Lol. I highly suggest you research the physics of balancing and imbalance issues. Any rotating part will benefit from being balanced; bar none. If you're that confident that a more solid object doesn't need to be balanced then let me know the next time you fly and I'll see if the A&P techs can remove one rotor blade from the compressor of an engine. After all, it's a solid mass so it can't cause an issue, right? Seriously... with some mechanical research you'll understand the varying orders of vibration and what is done to control them. End of rant.


I highly suggest you read up on the meaning of the word insignificant. To compare what happens in a bicycle tire/wheel with what happens in a jet turbine at 20,000 rpm is just plain nonsense. Again, you want to extrapolate from some other field to bicycle wheels. At the risk of repeating myself again, the weight of a valve stem or rim seam on a bicycle wheel does not affect the ride, nor can it be detected while riding.


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## been200mph (May 28, 2004)

Kerry Irons said:


> I highly suggest you read up on the meaning of the word insignificant. To compare what happens in a bicycle tire/wheel with what happens in a jet turbine at 20,000 rpm is just plain nonsense. Again, you want to extrapolate from some other field to bicycle wheels. At the risk of repeating myself again, the weight of a valve stem or rim seam on a bicycle wheel does not affect the ride, nor can it be detected while riding.


What may seem insignificant to you and some others is just one more small detail that is overlooked and a potential for improvement. Does it ride any better? For some it appears so as I'm not the only one who has been able to discern an imbalance in bike wheels/tires. Again, I have a pretty solid background which relates to understanding balancing of components and benefits of such work. Anyone who also has similar knowledge will also tell you that ANY rotating part WILL have a potential imbalance. Some pieces are made with enough precision and no variables so as to be perfectly in balance. Bike wheels and tires don't fall into this catagory, plain and simple. I am always open to learn but in this case you're being very close-minded and are just plain wrong. Anyhow... I should've quit before, seeing you are more stubborn than me, or not, lol. That's the beauty of the internet and our country; freedom to voice opinion. But please do some solid physical research before claiming that a bike wheel/tire can't be out of balance and/or cause a vibration.


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## Fixed (May 12, 2005)

*check it out?*

These kinds of arguments make me think of this quote:

<DL><DT>Aristotle maintained that women have fewer teeth than men; although he was twice married, it never occurred to him to verify this statement by examining his wives' mouths. <DD class=author>*Bertrand Russell*, _Impact of Science on Society (1952) ch. 1_
_British author, mathematician, & philosopher (1872 - 1970)_ </DD></DL>So, find a wheel that is out of balance on the stand, then ride it. Note observations. Balance the wheel, then repeat. Do this for many wheels, *then* draw conclusion. 

Lots of us draw conclusions about what *should* be the answer, but I think more often actually experimenting would be a better solution.


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## den bakker (Nov 13, 2004)

Fixed said:


> These kinds of arguments make me think of this quote:
> 
> <DL><DT>Aristotle maintained that women have fewer teeth than men; although he was twice married, it never occurred to him to verify this statement by examining his wives' mouths. <DD class=author>*Bertrand Russell*, _Impact of Science on Society (1952) ch. 1_
> _British author, mathematician, & philosopher (1872 - 1970)_ </DD></DL>So, find a wheel that is out of balance on the stand, then ride it. Note observations. Balance the wheel, then repeat. Do this for many wheels, *then* draw conclusion.
> ...


Maybe he did count. 








And hence the need for the scientific method  
(including blind tests)
Of course when this is done it's concluded here that mavic chose a bunch of morons that could not feel a thing, to take one specific example.


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## been200mph (May 28, 2004)

Fixed said:


> These kinds of arguments make me think of this quote:
> 
> <DL><DT>Aristotle maintained that women have fewer teeth than men; although he was twice married, it never occurred to him to verify this statement by examining his wives' mouths. <DD class=author>*Bertrand Russell*, _Impact of Science on Society (1952) ch. 1_
> _British author, mathematician, & philosopher (1872 - 1970)_ </DD></DL>So, find a wheel that is out of balance on the stand, then ride it. Note observations. Balance the wheel, then repeat. Do this for many wheels, *then* draw conclusion.
> ...


6g of weight were added by me to the valve stem of the front wheel to balance it to where it didn't shake when being rotated. The rear took 4g. This will change when the magnet for my yet-to-arrive Garmin 500 is installed. On smooth pavement before doing this I felt what can be described as a "surge" due to the imbalance. It's not there now after adding weight.


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## Fixed (May 12, 2005)

*fwiw*



Quixote said:


> KerryIrons, ever ridden Zipp 1080s without something like fishing weights to counter balance the extremely long valve stems? "Yikes", is all I can say. Tire preassure won't do anything for those wheels.


For what it's worth, I've ridden a TT bike with Zipp disc and Zipp 808 (both "unbalanced") at 60 mph (down an 8 mile long hill that drops 2,500', among others), and could not detect the slightest balance issue. This was with Zipp Tangent clinchers pumped to 120 psi.

But, out of full disclosure, I must be completely numb. I also cannot detect the "comfort" of some wheel designs vs. others. ;-)

My *speculation* is that the wobble we see on the stand is due to some kind of oscillation that gets started in the frame and/or stand, which cannot get going on the road, because the tire/wheel is pressed against the road, damping the oscillation.


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## ergott (Feb 26, 2006)

Of note with Zipp rims, they are always heavy at the valve hole before the tire is mounted. The tire only exacerbates this issue. If you feel a difference when you balance the wheel then do it. If you feel no problem then don't. Internet fighting always cracks me up.

-Eric


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## Fixed (May 12, 2005)

ergott said:


> Of note with Zipp rims, they are always heavy at the valve hole before the tire is mounted. The tire only exacerbates this issue. If you feel a difference when you balance the wheel then do it. If you feel no problem then don't. Internet fighting always cracks me up.
> 
> -Eric


I didn't start it. He started it.


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## ergott (Feb 26, 2006)

Fixed said:


> I didn't start it. He started it.



I telling on you.

-Eric


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## Kerry Irons (Feb 25, 2002)

*Momentum*



been200mph said:


> 6g of weight were added by me to the valve stem of the front wheel to balance it to where it didn't shake when being rotated. The rear took 4g. This will change when the magnet for my yet-to-arrive Garmin 500 is installed. On smooth pavement before doing this I felt what can be described as a "surge" due to the imbalance. It's not there now after adding weight.


So, it's your contention that 6 gm moving at 40 km/hr is enough force to either flex a tire with 7-8 bar pressure in it, or to cause noticeable vibration in a system with a total mass around 80-90 kg. I can't wait to see your calculations to support this claim


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## been200mph (May 28, 2004)

Kerry Irons said:


> So, it's your contention that 6 gm moving at 40 km/hr is enough force to either flex a tire with 7-8 bar pressure in it, or to cause noticeable vibration in a system with a total mass around 80-90 kg. I can't wait to see your calculations to support this claim


Show me solid proof that an imbalance CAN'T exist in a bicycle wheel/tire per your claims. I'd believe most bike issues are first order vibrations.


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## ergott (Feb 26, 2006)

Kerry Irons said:


> So, it's your contention that 6 gm moving at 40 km/hr is enough force to either flex a tire with 7-8 bar pressure in it, or to cause noticeable vibration in a system with a total mass around 80-90 kg. I can't wait to see your calculations to support this claim


I'm not doing any math here, but to add to the equation:
10g mass (worst case scenario)
33cm radius
about 540rpm (40mph or so)

Anyone want to take a stab at this one?

Don't forget that you could double the mass if you are dealing with 2 wheels in phase. When they are out of phase you would get a different sensation.

-Eric


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## skepticman (Dec 25, 2005)

been200mph said:


> Show me solid proof that an imbalance CAN'T exist in a bicycle wheel/tire per your claims. I'd believe most bike issues are first order vibrations.


You are the one making the claim that tiny imbalances in bicycle wheels are detectable by a rider. You have the burden of proof. See http://en.wikipedia.org/wiki/Negative_proof

I've never heard of a machine to balance bike wheels, never heard of a bike shop with one, never heard of pro racing mechanics with one, and never heard of any major wheel or rim manufacturer or professional wheel builder giving instructions to shops or customers on proper balancing of their wheels. I think Fulcrum/Campagnolo is the only manufacturer that (only in recent years) promotes the idea of a balanced wheel, and that looks like marketing hype to me. They don't seem to care that the valve stem, wheel magnet, or a non-uniform tube or tire will unbalance their allegedly balanced rim.

I've never detected any type of vibration in any of the wheels of any of the bikes I've owned in 20+ years. I'm guessing the vast majority of the people on this forum have the same experience. At the typical sustained speed (15-25 MPH, what is the RPM range anyway?) that an average rider typically rides for any length of time, and the weight of rider plus bike (140-220+ lbs), any vibrations from imbalance are negligible.

It's certainly possible that a grossly imbalanced tire or rim at very high speed could be detectable, but these circumstances seem very rare.

If you have links to any real scientific measurements or random double blind placebo controlled studies that show riders can detect vibrations from unbalanced wheel, then post them. Otherwise, you are just making unsubstantiated claims and this thread should stop now.


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## been200mph (May 28, 2004)

skepticman said:


> You are the one making the claim that tiny imbalances in bicycle wheels are detectable by a rider. You have the burden of proof. See http://en.wikipedia.org/wiki/Negative_proof
> 
> I've never heard of a machine to balance bike wheels, never heard of a bike shop with one, never heard of pro racing mechanics with one, and never heard of any major wheel or rim manufacturer or professional wheel builder giving instructions to shops or customers on proper balancing of their wheels. I think Fulcrum/Campagnolo is the only manufacturer that (only in recent years) promotes the idea of a balanced wheel, and that looks like marketing hype to me. They don't seem to care that the valve stem, wheel magnet, or a non-uniform tube or tire will unbalance their allegedly balanced rim.
> 
> ...


Even Ullrich understood issues with imbalanced wheels. It was rectified that year during the TDF. Do some research and you'll learn.


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## skepticman (Dec 25, 2005)

been200mph said:


> Even Ullrich understood issues with imbalanced wheels. It was rectified that year during the TDF. Do some research and you'll learn.


Post links or quotes of the research so we can all learn.


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## been200mph (May 28, 2004)

skepticman said:


> Post links or quotes of the research so we can all learn.


If memory serves me it was the '01 TDF. He had major issues especially descending and resolved the problem with a balanced wheelset. Fact. I'm just not one of the sheep who blindlly follows along; I am pretty damn analytical and also due to what I do am always trying to stay on the leading edge of technology. At least within my budget. And it's pretty damn inexpensive to balance a wheelset. I should've just let it go because too many here still also believe the Earth is flat... so, enjoy not balancing your wheelsets because you know imbalance just can't exist or be felt. ut:


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## WheresWaldo (Nov 29, 2005)

Even Jobst Brandt thinks bicycle wheel balancing is unnecessary
http://yarchive.net/bike/wheel_balancing.html

Bissell team mechanic feels the same way
http://bissellteammechanic.blogspot.com/2008/05/wheel-balance-issues-tall-riders.html

_Before anyone jumps on me for this post, at least I provided links. _


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## den bakker (Nov 13, 2004)

been200mph said:


> I am pretty damn analytical :


And yet, not a single number.


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## Mark Kelly (Oct 27, 2009)

The peak force due to an unbalance is given by 

F = M . ω^2 . r

At a linear velocity of around 11m.s^-1 a wheel with a diameter around 2m has a radial velocity about ω = 35s^-1, for mass of 6 g at a radius of 320 mm the peak force is thus a little under 5N. This represents approximately 1% of the static force supported by a typical tyre. 

For a tyre with a height around 25mm on which the static force represents a 15% compression*, the total static compression is 3.75mm. Taking first order effects only the force would cause the support point to move by around 0.04mm.

The frequency at which this is occuring is about 5 Hz which is well below the frequency of maximal human sensitivity to vibration.

It is hard to see this as a significant effect.

15% compression has been cited as the optimal inflation point for tyres, see http://www.vintagebicyclepress.com/images/TireDrop.pdf


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## Blue CheeseHead (Jul 14, 2008)

been200mph said:


> 6g of weight were added by me to the valve stem of the front wheel to balance it to where it didn't shake when being rotated. The rear took 4g. This will change when the magnet for my yet-to-arrive Garmin 500 is installed. On smooth pavement before doing this I felt what can be described as a "surge" due to the imbalance. It's not there now after adding weight.


A pea under your matress must drive you nuts. 

6 grams spinning around a .35 m radius at 20 mph (8.8m/s) generates a centripedal force of about .3 pounds. Given the inertial resistance in accelerating a human's mass + bike, I find it remarkable that once could sense a "surge". Kudos:thumbsup:


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## ergott (Feb 26, 2006)

Blue CheeseHead said:


> A pea under your matress must drive you nuts.
> 
> 6 grams spinning around a .35 m radius at 20 mph (8.8m/s) generates a centripedal force of about .3 pounds. Given the inertial resistance in accelerating a human's mass + bike, I find it remarkable that once could sense a "surge". Kudos:thumbsup:


I don't know the formula you cite, but please plug in:
10g (could even be more if you put a wheel magnet in the wrong place)
40mph

The mass could even be doubled if both wheels are in phase.

-Eric


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## rruff (Feb 28, 2006)

Mark Kelly said:


> For a tyre with a height around 25mm on which the static force represents a 15% compression*, the total static compression is 3.75mm. Taking first order effects only the force would cause the support point to move by around 0.04mm.


Thanks... and even if you have glass-smooth roads, the rim and tire will be more out-of-round than this.


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## ergott (Feb 26, 2006)

rruff said:


> Thanks... and even if you have glass-smooth roads, the rim and tire will be more out-of-round than this.


Maybe _your_ wheels!

;-)

JK

-Eric


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## rruff (Feb 28, 2006)

Ha! If you are making your rims that round, you must have a more "perfect" source than I do. 

And where can you find tires that round?


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## cranecamsou (Mar 15, 2008)

Sounds like we have two arguments here.

1) Can a perfectly round wheel exhibit out-of-balance vibrations with highly inflated tires?
Answer - Yes. This is simple physics, and is absolutely true. An out of balance wheel made of solid aluminum (perfectly round) can jump off the pavement at speed. Remember, out-of-balance means it will act on the wheel in all directions of the rotation. The tire will want to jump up and down, just like it will surge forward and back. Tire compression is not affected with this forward/backward surging, and tire compression isn't the gate-keeper for wheel vibrations.

2) Will an out of balance wheel (within reason) exhibit percievable vibrations to the rider?
Answer - Probably not. Tire, wheel, bike, rider weight largely negates the few grams we're talking here. Real world road surface will also wash out any balance issues. But, it's important to note that it's very possible someone has noticed it.....just not me.


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## been200mph (May 28, 2004)

cranecamsou said:


> Sounds like we have two arguments here.
> 
> 1) Can a perfectly round wheel exhibit out-of-balance vibrations with highly inflated tires?
> Answer - Yes. This is simple physics, and is absolutely true. An out of balance wheel made of solid aluminum (perfectly round) can jump off the pavement at speed. Remember, out-of-balance means it will act on the wheel in all directions of the rotation. The tire will want to jump up and down, just like it will surge forward and back. Tire compression is not affected with this forward/backward surging, and tire compression isn't the gate-keeper for wheel vibrations.
> ...


Bingo. The only time I was able to notice a "surge" was on a fairly smooth surface. Some may not feel it as others would even on the same bike if they weigh the same. From a scientific standpoint there is NO way a person can say there can't possibly be an imbalance situation, period. When Ullrich and Riis pay enough attention to do something you know it's not just a figment of my imagination. Anyhow... enough typing... time to ride before it rains again. I'll say this... at least this board is civil enough that we can have a good discussion/debate without childish name-calling/etc. We're all here for the same reason... we have a love for cycling. No matter what never lose that and become mentally imbalanced!


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## ChilliConCarnage (Jun 1, 2006)

Kerry Irons said:


> If you are sensing vibrations it is from an out of round wheel (rim or tire) or out of true wheel, not from an out of balance wheel...


+1

I believe, like many (if not most) internet "discussions", people get hung up on a single term that they interpret differently. In this case, I think that some people may be saying "out of balance" when "out of true" would be the correct term.



been200mph said:


> Show me solid proof that an imbalance CAN'T exist in a bicycle wheel/tire per your claims...


I don't recall anybody saying an imbalance is impossible to exist in a bicycle tire - only that the imbalance would have to cause a deformation in the tire to be felt. Which is highly unlikely. On the ther hand, and out-of-true tire would cause a sensation that is easily felt.

As the Bissell team mechanic put it:



> The reasons you see poorly balanced wheels are due more to things like issues with spoke tension (radial trueness), and improper bead seating with clincher tires or poorly seated tubular tires. You get a lot of that with tubular tires, wheel hop due to poor seating


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## Blue CheeseHead (Jul 14, 2008)

ergott said:


> I don't know the formula you cite, but please plug in:
> 10g (could even be more if you put a wheel magnet in the wrong place)
> 40mph
> 
> ...


F=mv^2/r where 

m=mass(kg)
v=velocity (meters/sec)
r=radius (meters)

F=Newtons=.010*(40mph*.44m/s per mph)^2 / .35 = 8.85 Newtons *.225 = 2 pounds


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## Jim311 (Sep 18, 2009)

My mountain bike tires are way out of balance but it is completely impossible to recognize even at high speeds on smooth pavement. It is possible that a tire could be out of balance but if it were far enough out to actually NOTICE it would be one seriously screwed up tire.


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## Kerry Irons (Feb 25, 2002)

*Back to zilch*



been200mph said:


> Bingo. The only time I was able to notice a "surge" was on a fairly smooth surface. Some may not feel it as others would even on the same bike if they weigh the same. From a scientific standpoint there is NO way a person can say there can't possibly be an imbalance situation, period. When Ullrich and Riis pay enough attention to do something you know it's not just a figment of my imagination. Anyhow... enough typing... time to ride before it rains again. I'll say this... at least this board is civil enough that we can have a good discussion/debate without childish name-calling/etc. We're all here for the same reason... we have a love for cycling. No matter what never lose that and become mentally imbalanced!


Nobody here has ever said that wheels couldn't be unbalanced. In fact, we all agree that virtually every wheel IS unbalanced. You have brought in irrelevant examples from automotive, aeronautics, and motorcycles to "prove" that this effect is somehow significant. Numerous people have reported otherwise, and adequate theoretical math has demonstrated likewise. Again, it's the significance of zilch.

BTW, the problem Ulrich was having was never specifically attributed to wheel balance, but rather crosswinds, wheel true/roundness, and Ulrich's own abilities.


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## been200mph (May 28, 2004)

Kerry Irons said:


> Nobody here has ever said that wheels couldn't be unbalanced. In fact, we all agree that virtually every wheel IS unbalanced. You have brought in irrelevant examples from automotive, aeronautics, and motorcycles to "prove" that this effect is somehow significant. Numerous people have reported otherwise, and adequate theoretical math has demonstrated likewise. Again, it's the significance of zilch.
> 
> BTW, the problem Ulrich was having was never specifically attributed to wheel balance, but rather crosswinds, wheel true/roundness, and Ulrich's own abilities.


I'm not the only person who has been able to discern vibrations aka oscillations from an imbalance. Some in here and other venues have claimed to have had smoother rides after balancing the wheels. One was pretty clear it wasn't a placebo effect. The thing is I'd believe it would be more noticed in a lightweight wheelset where say 5g at the rim has more significance than 5g at the rim of a heavier wheel. My wheelset is just over 1300g which isn't bad for aluminum clinchers. Tire stiffness, spoke count/material/tension, fork material, frame material, etc. would certainly all have input into what is transmitted to the bar. One thing that I still say is totallly wrong is your claim that suspension or the lack therof has any effect in whether or not an imbalance can be transmitted to a frame/chassis/etc. Anyhow... it's been a good discussion and we each have our unbending opinion which we certainly won't be changing anytime soon most likely, lol. Have a good weekend and I hope to have one as well. :thumbsup:


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