# Plan A or plan B?



## cry lion (May 28, 2011)

Hi I have been commuting with my mtb, its an "all mountain bike" but it has a rigid up front. My commute was about 35km in total and it was quite obvious a mtb was not really optimal, at least no the one I have. My ass felt sore, and I found out a 25mm riser bar does not really give you a lot of choices where to put the hands, many times did I wish for one of those long triathlon bars so I could just lay down and stretch out.

Also a 60 year old man on a road bike passed me like I was a senior citizen, on a fast down hill he just rolled away while I was pedaling! WTF. I have the wrong kind of bike was my first thought.

So I started thinking about maybe getting me one of those roadies too. I have been looking at something that takes discs, steel, and and 40mm tires, and fenders and a rack. Nokian has the only good winter tires and those are 40mm (the good ones). It would be an all year bike. AND I want to run bullhorn bars...

Are "regular geo" roadies suitable for bullbars? Or should I go one size longer or shorter?

This was plan A.

I have a question about angles, specifically the seat tube angle, is there much power lost when its like 70 degrees instead of like 73? Mountainbikes are usually a bit slacker than roadies and I wonder do those extra degrees make a roadie more efficient? If yes, how much? A few minutes on my commute or like several seconds?

Wheel size once and for all, does a 700C roll faster than a 26"? Yes? Why? How much can I expect from upgrading to road bike? Anyone tested this?

Plan B 

Plan B is a bit cheaper, since I already have a frame, its another all mountain frame. A Chromag Sakura, handmade in Canada. My plan was to get a ridid fork for it and bullbars, I would be using much better parts for this one, like hubs, cassette, rims, shifters, well almost everything would be better since I don't have to but another frame or winter tires.

What would you guys have done? Build on what you have or buy everything new?
I get a really good commuterized mtb, or a so so roadie for the same money.


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## Straz85 (May 12, 2011)

Using a XC bike with a few changes as a commuter would be one thing, but to use an AM bike with a really slack head angle isn't going to be great. Hell, even last night when I rode my Trek Fuel EX8 1.5 miles to the trailhead on pavement it felt inefficient, to say the least, and that's a "trail bike" with a slightly steeper head angle that your Chromag probably has.

I have a couple bikes that I can commute on. I usually use my road bike because I just find that the most efficient, but with 25c tires, it's not the most comfortable ride. I also built a Nashbar mountain bike frame with spare parts, it has a SRAM X5 1x9 drivetrain with a 38T ring up front and 26x1.5" road tires (equivalent width to 38c). 

I find the road bike far more efficient, I get bored riding the commuter 10 miles each way too. I would suggest picking up an old steel road bike that will take slightly wider tires. Not sure you need tires as wide as you mentioned, I would suggest 28c or 32c (if they fit), something with some good flat resistance. I think you can also get studded tires in those sizes. I personally prefer drop bars, once you get used to them, which doesn't take long, they're great. 

As far as seat tube angles go, a 70 degree seat tube will put you further behind the BB than say, a 73 degree, which will have you using different muscles to pedal, and you will likely lose some power and efficiency. You'll be using your hamstrings more instead of your quads.


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## cry lion (May 28, 2011)

I measured my head angle and seat angle today (using trigonometry) and the head angle is 72.52 degrees or very close. Seat tube is somewhere 73.72-73.97 degrees. So the angles are not that slack anymore. And this maybe means the smaller type of frame is creating the feeling of inefficiency. Or possibly handlebar too high? Or wrong type of handlebar. I don't know. 

Longer wheelbase, smaller wheels, Fat tires could be it. And finally weight, is weight of the wheels or complete bike something you actually feel when on the bike or is this just a myth? The tires are not exactly the skinny kind, and the whole build is pretty heavy too (I estimate 26-28lb).


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## blakcloud (Apr 13, 2006)

From my experience, angles have nothing to do with efficiency. The slightly slacker seat tube angle is for putting more weight on the rear wheel for traction and it allows the top tube to be longer for the stretch that you need on a mountain bike.

I think you are looking at this all wrong. Depending on the size of your rims, you could put on Specialized 26 x 1 tires and you just saved at least a pound per wheel. This is where your biggest buck for the dollar should go. The lighter the wheels the easier it is to get the bike up to speed and allows that quick acceleration that will make the bike feel lively. For the extra hand positions try some of those new Ergon grips with bar ends. I wouldn't use bull horns as mountain bikes have longer top tubes than most road bikes and the bull horns will stretch you out too far unless you get a small reach stem. 

Lots of people use mountain bikes for commuters, so they work. Your rigid fork was also a good choice to lessen the weight. Sure you could buy a new bike but you have something that can work if that is what you want.


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## Guest (Sep 5, 2011)

> Also a 60 year old man on a road bike passed me like I was a senior citizen, on a fast down hill he just rolled away while I was pedaling! WTF. I have the wrong kind of bike was my first thought.


This is mostly aerodynamics on a downhill. Mountain bikes will generally have the rider in a more upright position (for better handling) but that means you have to push an upright body with a large cross-section trhough the wind. On a road bike leaned over in the drop position you can cut your effective drag profile substantially half compared to a mountain bike. At high speed that's a big deal as aerodynamics is by far the dominant form of resistance -- power needed to overcome air resistance is proportional to the cube of the wind-speed (so at 26mph vs 13mph, you are using 8X as much power overcoming wind). 

For streamlined "human power vehicles" the record for an hour is in excess of 70mph on level roads, compared to low 30s for traditional cyclists because it's almost 100% aerodynamics at those speeds. 

If you cared about trying to keep up fast average speeds on the commute , or if your commute has lots of descents, something with drop handlebars but capable of supporting a rear rack, like a touring or cross bike would be your best bet. And as far as drag goes, it would be better if you can fit most of what you need to carry in a trunk bag on top of your rack, rather than hanging from the sides, so it's in your body's slipstream. 

I personally am riding a short, commute in town on level roads, and I'm riding and lock up outsides so I can't have anything too nice (or it will be stolen). I'm running a flat bar hybrid bike. When I first started commuting it was on a mountain bike and the hybrid is actually far better, even though it's still more upright than a true roadbike. Though in my case, reduction in weight and in tire friction compared to a mountain bike is a bigger deal in slow speeds and stop-and-go traffic. 




blakcloud said:


> From my experience, angles have nothing to do with efficiency. The slightly slacker seat tube angle is for putting more weight on the rear wheel for traction and it allows the top tube to be longer for the stretch that you need on a mountain bike.
> 
> I think you are looking at this all wrong. Depending on the size of your rims, you could put on Specialized 26 x 1 tires and you just saved at least a pound per wheel. This is where your biggest buck for the dollar should go. The lighter the wheels the easier it is to get the bike up to speed and allows that quick acceleration that will make the bike feel lively. For the extra hand positions try some of those new Ergon grips with bar ends. I wouldn't use bull horns as mountain bikes have longer top tubes than most road bikes and the bull horns will stretch you out too far unless you get a small reach stem.


This is a good point. Dropping weight on the wheel, particularly in the tires, actually counts double in terms of inertia / effort it takes to accelerate - since you have to both move the actual weight of the wheel, and rotate the wheel (wheel circumference = forward displacement for a revolution, hence the doubling) it's effectively twice as much mass as carrying the tires on your back would be.


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## Mr. Versatile (Nov 24, 2005)

If it were me I'd look for a road bike (maybe used) and forget about modifying the mt. bike. You said you wanted to use upright bars so perhaps a hybrid would suit you.


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## cry lion (May 28, 2011)

What about wheel size? If a 26 and a 700 is both 24mm and they weigh the same, (tires rims) is there any practical difference for the rider? 

I mean is there anything to gain going up in diameter, is bigger better? What about real world data where the 700c wheel has heavier rim, and heavier tire and the spokes are longer (more weight)?

So wind is the enemy, I guess I missed the big elephant.

MR versatile. No I want either bull horn (short ones like permanent bar ends) or something like this


















I just realized I want a bike similar to that one


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## StageHand (Dec 27, 2002)

Get a Surly Cross Check complete. Swap the bars out for bull horns. Or keep it stock for a while, see if you like it. You can run up to 45mm tires, I think, without fenders.


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## Scot_Gore (Jan 25, 2002)

StageHand said:


> Get a Surly Cross Check complete. Swap the bars out for bull horns. Or keep it stock for a while, see if you like it. You can run up to 45mm tires, I think, without fenders.


I'll 2nd this. 

There's a reason it says FFF on the side, "Fatties Fit Fine".

Scot


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## cry lion (May 28, 2011)

Hello gentlemen. Non disc frames is a nono for me, its cold and rainy and icy and sh!t way too much here. I love discs and I aint never going back no matter what. 

Anyway I just had a long hard look at my Sakura frame and you know what? It has really nice welds and its very well made, I will build it up and that will be my lowcash bike+ I can use it in the winter with real nokians, going without is suicide. Its going to be around 1 degree slacker than my current one but ride much much better. Gonna sell the alu hog.

I have pretty much given up on finding a do it all 700c bike, or maybe I should say I found them, but those are really boring bikes if you think about it so insted I'm gonna save up for one of those Speedsters! But a much more badass one.

The only make custom bikes so its probably the last bike I'll ever buy, being titanium and all it could get very cheap per year compared buing new and selling when you get tired, and I would NEVER get tired of one of those, just look at it. A bike like that would probably get me puzzy  God damn!

But yeah why trying to find the right/best bike over and over when they do a custom one for me, and it looks good as hell to, and is indestructable, don't rust, no paint to get worn, and I can have it any way I want. 

Oh yeah i almsot forgot, I did some calculating on that bike calculating site and pulled some figures out of my ass but came up with that at 10m/s I use 250w and with a good road bike I can go 12m/s insted for those same 250w.

And at 127w / 7,5m/s / about 27km/h which is about what I average on my commute I could go 9,23m/s instead. Much of it being due to lower frontal area cm2 of course. 

I also read a blog and it said its about 10% less rolling resistance in the big tires all else being equal (which they never are) and 10% in the hub bearings just by the 700c wheel having 10% longer circumference. 

All in all life is too short to ride unsexy bikes


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