Crank arm Length for 29er

[M L]

Ses van die een half dosyn van die ander.

Edited November 27, 2012 by wheelerdealer

[RacerX]

DG also used EPO.

 

I use 180mm cranks on all my bikes. Works nicely on the 29er.

Cool, me too! Glad to see I'm not *that* weird

 

Ahem, use 180mm cranks, not EPO, hehe

Edited November 27, 2012 by RacerX

[braailegend]

5mm.. really? just checked it on a ruler.. mathematically you'll get difference in torque, but really?

[covie]

5mm.. really? just checked it on a ruler.. mathematically you'll get difference in torque, but really?

 

Quite correct 5mm will make no difference in ground clearance of BB hight, especailly as your supposed to keep pedals level when you see an obstacle that might hit your cranks. Same applies for DH/AM bikes they have very low BB's and you dont hear them going on about clearance. The balance outweighs the occasional BB hit.

[Brian Fantana]

Same applies for DH/AM bikes they have very low BB's and you dont hear them going on about clearance. The balance outweighs the occasional BB hit.

 

Not sure what you mean by this as AM bikes have higher BB heights than XC bikes. DH bikes in turn have higher BB heights then AM bikes. The only time the BB gets low is when the suspension goes through it's travel.

[covie]

Not sure what you mean by this as AM bikes have higher BB heights than XC bikes. DH bikes in turn have higher BB heights then AM bikes. The only time the BB gets low is when the suspension goes through it's travel.

 

Quite correct when the suspension is not compressed, measure it when you reach full compression. And you find they sag lower.

[Stig]

The crank arm length has to do with a proportion to your femur length.

Has nothing to do with wheel size, gearing will sort that out.

[RockCoach]

DG also used EPO.

 

And what does than have to do with crank length?

 

Knowing that LA was involved in doping does not take away from the fact that he was a superb time-trialist and climber - almost always with a pretty high cadence. I'm sure he'd run different crank lengths on the different bikes.

[Danger Dassie]

Quite correct when the suspension is not compressed, measure it when you reach full compression. And you find they sag lower.

 

Exactly, but for the most part not everyone is on DH/AM rigs with big travel. The 5-10mm makes a huge difference. Explain how you keep your pedals level on an extended rocky climb?

[covie]

Exactly, but for the most part not everyone is on DH/AM rigs with big travel. The 5-10mm makes a huge difference. Explain how you keep your pedals level on an extended rocky climb?

 

Most serious BB hits are going down in my experiance and that just means you level your pedals if you see you are about to hit. As far as clibming rocky sections. I find that doing a simple unweighting,front and rear saves my BB from being hit every time. 5mm is going to make no difference on a rocky climb. 2cm might but not 5mm.

[covie]

here is a good explanation on crank length and why we have variable sizes.

http://sheldonbrown.com/cranks.html

[Danger Dassie]

Most serious BB hits are going down in my experiance and that just means you level your pedals if you see you are about to hit. As far as clibming rocky sections. I find that doing a simple unweighting,front and rear saves my BB from being hit every time. 5mm is going to make no difference on a rocky climb. 2cm might but not 5mm.

 

Of all the bikes I've ridden, my experience is different. Those 5-10mm definitely make a difference on a rocky climb, van Gaalen specifically.

[carbon29er]

Most serious BB hits are going down in my experiance and that just means you level your pedals if you see you are about to hit. As far as clibming rocky sections. I find that doing a simple unweighting,front and rear saves my BB from being hit every time. 5mm is going to make no difference on a rocky climb. 2cm might but not 5mm.

Of all the bikes I've ridden, my experience is different. Those 5-10mm definitely make a difference on a rocky climb, van Gaalen specifically.

Crank length makes ABSOLUTELY no difference to BB hits.

 

Maybe to pedal strikes but definitely not BB strikes.....the only thing that CAN make a difference to BB hits is reducing the head angle by decreasing the A2C of your fork.

[Danger Dassie]

Crank length makes ABSOLUTELY no difference to BB hits.

 

Maybe to pedal strikes but definitely not BB strikes.....the only thing that CAN make a difference to BB hits is reducing the head angle by decreasing the A2C of your fork.

 

I never mentioned BB hits, I was referring to cranks and the clearance thereof. Two different things.

[Brian Fantana]

Most serious BB hits are going down in my experiance and that just means you level your pedals if you see you are about to hit. As far as clibming rocky sections. I find that doing a simple unweighting,front and rear saves my BB from being hit every time. 5mm is going to make no difference on a rocky climb. 2cm might but not 5mm.

 

How can something hit your BB without hitting your chainring moer-toe??

[Guest ctMTBer]

And what does than have to do with crank length?

 

Knowing that LA was involved in doping does not take away from the fact that he was a superb time-trialist and climber - almost always with a pretty high cadence. I'm sure he'd run different crank lengths on the different bikes.

Why would you run different crank lenghts? This will affect your optimum power and which muscles you use. Once your have the correct size for your BODY you should keep to that.