gclark8 said:Its not about longer or shorter.
It is part of bike fit.
There is only one correct crank length for any given leg length.
I ride almost exclusively on the flats, its hard to find a hill in Louisiana. I'm 6ft tall with 33" inseam. I have a standard geometry steel framed bike. I have been planning on upgrading the crankset. Currently use 170s, thinking of 175s. 1/2 centimeter does not seem like a big difference, but I'm learning as I go. I'll prbably get the 175s and see how it goes, I hope I don't have to put the old set back on.FreeHueco said:But there is also the factor of what sort of riding you do! If you want to spin as fast as possible, a shorter crank will be better. If you need the leverage for climbing a longer crank will be better.
I am 6' tall, and use a 172.5 crank on both bikes. As soon as I can, I am going to swap out the crank on my single-speed for a 165. I just can't spin fast enough to get my speed up where I want it.
stilesiii said:I ride almost exclusively on the flats, its hard to find a hill in Louisiana. I'm 6ft tall with 33" inseam. I have a standard geometry steel framed bike. I have been planning on upgrading the crankset. Currently use 170s, thinking of 175s. 1/2 centimeter does not seem like a big difference, but I'm learning as I go. I'll prbably get the 175s and see how it goes, I hope I don't have to put the old set back on.
170 is really short for your height. I'd recommend changing to 172.5 first before making the jump to 175. It is a noticeable change. I have two bikes, one with 172.5's, one with 175's, I prefer the 175 bike for hills, but the 172.5's in the flats. It can spin that much easier.stilesiii said:I ride almost exclusively on the flats, its hard to find a hill in Louisiana. I'm 6ft tall with 33" inseam. I have a standard geometry steel framed bike. I have been planning on upgrading the crankset. Currently use 170s, thinking of 175s. 1/2 centimeter does not seem like a big difference, but I'm learning as I go. I'll prbably get the 175s and see how it goes, I hope I don't have to put the old set back on.
From (which offers custom cranks)stilesiii said:I know this is a dumb question, but what is the effects of longer crank arms.
Better for flats?
I'm not shooting the messenger, but......djconnel said:From (which offers custom cranks)
http://www.zinncycles.com/cranks.aspx
Here is the formula I recommend:
Crank length (mm) = Inseam (mm) X 0.216
Or, more conservatively for tall riders:
Crank length (mm) = Inseam (mm) X 0.21
531Aussie said:I'm not shooting the messenger, but......
I don't like that formula, in fact, I don't think anyone does
There's no pro in the world over about 5'5" is using cranks relatively that long. I don't know how Zinn still gets away with it. I'm only 6ft, and the "conservative" formula puts me on 188mm cranks. It's crazy!
Hmm, I'd say you have unusually short legs. Is that your pants inseam or your real inside leg measurement, crotch to floor? That is VERY short for someone 6ft. You've got shove the tape or the clipboard right up there to get the right measurement.FreeHueco said:Does that mean you have abnormally long legs? I get 171 or 175 when I use that formula (6'0" with 32 inch inseam)...
531Aussie said:What is it with every Yank knowing their pants inseam? Is it part of the college curriculum?
531Aussie said:Hmm, I'd say you have unusually short legs. Is that your pants inseam or your real inside leg measurement, crotch to floor? That is VERY short for someone 6ft. You've got shove the tape or the clipboard right up there to get the right measurement.
What is it with every Yank knowing their pants inseam? Is it part of the college curriculum?
I do have longish legs: my inside leg is ~35.2" (89 to 89.5cm, 'depending'..)
But you still need to measure your own body parts to get a frame of reference, no?FreeHueco said:The college curriculum is actually learning how to measure someone else's inseam without a tape measure...
alienator said:Knowing our inseam measurement is a critical component in getting our jackboots to fit right. Poor fitting jackboots screw up the pleats on our uniform pants. If there's one thing we believe here in the USofA, it's that we like our jackboots to fit right and look snappy when we liberate other people in the world from their bodies. You prolly didn't realize it but the drumbeat of the spread of freedom is tapped out by our jackboots hitting the bricks, kickin' in doors, and stompin' villagers' heads.
Jeez. Don't you get the news down under?
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