Crank arm length: Anybody switched to shorter

[dekindy]

The recent question about crank arm length prompted me to read more about the study referenced on RoadBikeRider.com that concluded that crank arm length did not matter when it comes to producing more power. However it does matter when it comes to efficiency. Less oxygen is consumed with shorter cranks and aerodynamics are also improved because you can ride in a lower position.

So, has anybody over 6 feet have experience with switching from 175 to 165 cranks?

Conversely, has anyone switched to longer cranks and been disappointed?

[thegunner]

oddly enough, i'm a short rider (5'7") and i went from 170 to 175. i just preferred the low cadence type riding. it suits me personally since in rowing i was always better at low stroke rate anaerobic work.

to each their own!

[dekindy]

oddly enough, i'm a short rider (5'7") and i went from 170 to 175. i just preferred the low cadence type riding. it suits me personally since in rowing i was always better at low stroke rate anaerobic work.

to each their own!

That was the observation that I received when I did a VO2 max test at the National Institute of Fitness and Sport. They were impressed with my anaerobic capacity but felt my aerobic capacity needed a lot of work. The solution was to work on my aerobic capacity which is what I want to do rather than emphasize my anaerobic system. So I want to go in the opposite direction and ride at a higher cadence. Does this make sense?

[Velosmith]

I am 5'9" and had ridden 172.5 for years. When I picked up fixed gear riding about 4 years ago I went to 170 to minimize pedal strikes. After a year I dropped to 165 for a little while and it just felt too tight. I landed an old set of Campy Strada cranks at 167.5 and as Goldie Locks says it was "just right".

Gears, I'm still on 170mm now and am happy. I still logically can't tell you why such small differences in the length make such a large difference is pedal stoke. I chock it up to muscle memory or just voodoo.

[oldguy00]

......and aerodynamics are also improved because you can ride in a lower position.
...

I think you have that backwards...
If you shorten your cranks by, say, 2.5mm, you will need to -raise- your saddle by that amount (think about your crank arm on the down stroke @ 6 o'clock).
Regardless, the difference in height is so minimal that I wouldn't use aerodynamics as a determining factor at all.

I'm 5'10, have a somewhat short inseam for my height, ride a 73cm saddle height with bonts & speedplays. I've tried 170 & 172.5, and always end up back at 175's. Just feels right for me. That said, I'm not a 'spinner'.

[CaptStash]

oddly enough, i'm a short rider (5'7") and i went from 170 to 175. i just preferred the low cadence type riding. it suits me personally since in rowing i was always better at low stroke rate anaerobic work.

to each their own!

Interesting. I never made that connection. I prefer to spin at a farily high cadence, and had my biggest successes rowing when I was maintaining a high rate as well.

CaptStash....

[thegunner]

Interesting. I never made that connection. I prefer to spin at a farily high cadence, and had my biggest successes rowing when I was maintaining a high rate as well.

CaptStash....

haha, i defy all odds. i shouldn't have been rowing at 5'7" to begin with. it infuriated my coach to no end when i did my 10k test at a 22. he thought i wasn't trying.

[nm87710]

That was the observation that I received when I did a VO2 max test at the National Institute of Fitness and Sport. They were impressed with my anaerobic capacity but felt my aerobic capacity needed a lot of work. The solution was to work on my aerobic capacity which is what I want to do rather than emphasize my anaerobic system. So I want to go in the opposite direction and ride at a higher cadence. Does this make sense?



Good Luck!

[dekindy]

I think you have that backwards...
If you shorten your cranks by, say, 2.5mm, you will need to -raise- your saddle by that amount (think about your crank arm on the down stroke @ 6 o'clock).
Regardless, the difference in height is so minimal that I wouldn't use aerodynamics as a determining factor at all.

I'm 5'10, have a somewhat short inseam for my height, ride a 73cm saddle height with bonts & speedplays. I've tried 170 & 172.5, and always end up back at 175's. Just feels right for me. That said, I'm not a 'spinner'.

Good observation. For us regular riders the seat height would have to be raised.

I did not note the fact that the reference to lower saddle height was in relation to time trialing and getting the rider moved forward and downward for aerodynamic gains. The shorter crank arm lessens the restriction of the knees hitting the rib cage and allows for a more forward and downward position. Power output might be lessened but more than offset by less aerodynamic drag.

Maybe I will just stick with what I have since my fitter has responded to my inquiry and states that longer cranks are better for hill climbing which is my weakness.

[benb]

I have been using 175s the last 10 years, except for one year I accidentally ordered 172.5 cranks from Performance.. I thought I would try it.

I rode them for that whole year.. I definitely thought it helped my spin, but I swear it hurt my climbing. I also had a fixie that had 165s.. I could really feel the difference, but that bike was so slow it's hard to make any comparison. I think it was a misguided attempt to have some extra pedal clearance.. it was stupid cause that bike had SPDs on it that definitely had poor clearance.

I went back to 175s and haven't looked back, I've never had an issue with low cadence personally.

(I'm 6'1")

[Auk]

Hmmmmmm, a shorter crank doesn't seem to have ill effects on top track riders you put out stupidly high wattage numbers.

[Charles M]

PART BODY MEASURES AND FIT...

PART PERSONAL PREF.

That's it...

[rustychisel]

hmmm, four bikes, two with 172.5mm cranks, one fixed with 172.5mm, one fixed with 167.5. Mostly I can tell the difference for the first 10km of a ride then it becomes a non-issue. At 5'10 I 'prefer' 172.5mm but I agree it's a moot point.

[djg21]

The recent question about crank arm length prompted me to read more about the study referenced on RoadBikeRider.com that concluded that crank arm length did not matter when it comes to producing more power. However it does matter when it comes to efficiency. Less oxygen is consumed with shorter cranks and aerodynamics are also improved because you can ride in a lower position.

So, has anybody over 6 feet have experience with switching from 175 to 165 cranks?

Conversely, has anyone switched to longer cranks and been disappointed?


I used a 165 on the track for a while and then switched up to a 170. I ride a 175 on the road. I actually have a set of DA 7800 cranks in a 175 I'd like to swap for 177.5s if anyone has some!

[eddief]

172.5 on most. these days 170 on road bikes, 152 with mt Q-rings on long wheel base recumbent. no standing on that bent, so spin baby spin with short cranks.