I am 5'10" and my inseam is 34". My San Andreas has a high BB and I like to run my seat a tiny bit on the low side for all mountain type of riding. I was thinking about upgrading to the new type of cranks with a hollow spindle and outboard bearing BB and I was wondering if 180mm crank arms would be good for me.
180mm crank arms pros and cons?
Shawn in da Canyon
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The length of everyones legs causes there to be a natural "period" similar to the length of the ballast on a grandfather clock. The further outside this period you are, the harder it will be to maintain that pace. So yeah, I can see how making the larger movement gets more difficult.brent878 said:
The difference is circumference between a 175mm crank and a 180mm crank is 5mm * 2 * pi ≈ 31.4mm ≈ 3cm. It doesn't seem like a lot, bot I can see how someone with a honed cadence can get messed up by this change.
chain concern
Also, there are some frame-bike configurations where too much torque is a possibility with 180's. I think high-end, butted frames, I'm thinking singlespeed particularly, can flex enough to get chain roll-off if you are really pulling on the bar and mashing on the pedal.
Also, there are some frame-bike configurations where too much torque is a possibility with 180's. I think high-end, butted frames, I'm thinking singlespeed particularly, can flex enough to get chain roll-off if you are really pulling on the bar and mashing on the pedal.
one thing not mentioned yet
longer crank arms mean that when your leg is up, your knee has to bend more sharply, alot of people end up with knee problems.
also, your higher BB will get to be less of an advantage because the longer crankarms will be closer to the ground and snaging and smacking things more often
longer crank arms mean that when your leg is up, your knee has to bend more sharply, alot of people end up with knee problems.
also, your higher BB will get to be less of an advantage because the longer crankarms will be closer to the ground and snaging and smacking things more often
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We are talking about 5mm, approximately 3/16ths of an inch, not even 1/4 of an inch. To the ultra sensitive finely tuned rider it might make a difference. To the unsophisticated clod like me, it's all a positive.dan0 said:
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Cadence aside
I guess if you are a disciplined cadence guy, they might have some negative impact, but in all honesty, how many of us are? I know I try, but when things get hairy I mash just like most dudes. Old habits are hard to break
Having BMX background, I always ran 180's on my 20" bike and 185- 190's on my 24" cruiser. The extra length gave me more leverage and snap out of the gate. My whole game was leg strength, and I could pull a taller gear with the long crank and still out accelerate most everyone. One I was up to speed the tall gear helped me pull away.
This was the days before BMX tracks became the obstacle courses they tend to be knowadays, so this set up served me well.
Im only 5'8" with a 30" inseam. If I had longer legs, I'd upgrade my MTB to longer cranks (I run 175's) For long MTB rides with alot of climb (not BMX sprints) I'd be worried about the impact that the increased overall stroke distance (top dead center to bottom dead center) might have on my aging and feeble knees! If I had long legs, I'd be all over it!
One old man's opinion! haha
I guess if you are a disciplined cadence guy, they might have some negative impact, but in all honesty, how many of us are? I know I try, but when things get hairy I mash just like most dudes. Old habits are hard to break
Having BMX background, I always ran 180's on my 20" bike and 185- 190's on my 24" cruiser. The extra length gave me more leverage and snap out of the gate. My whole game was leg strength, and I could pull a taller gear with the long crank and still out accelerate most everyone. One I was up to speed the tall gear helped me pull away.
This was the days before BMX tracks became the obstacle courses they tend to be knowadays, so this set up served me well.
Im only 5'8" with a 30" inseam. If I had longer legs, I'd upgrade my MTB to longer cranks (I run 175's) For long MTB rides with alot of climb (not BMX sprints) I'd be worried about the impact that the increased overall stroke distance (top dead center to bottom dead center) might have on my aging and feeble knees! If I had long legs, I'd be all over it!
One old man's opinion! haha
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I run 175's, but have also run 170's. I like the 175s better.
I don't know if I've ever seen 165's
I don't know if I've ever seen 165's
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