shorter cranks

Classyrider

What are your thoughts in using shorter cranks? For example, I am 1m65cm and I was recommended to ride 165mm cranks. I tried them and find that there is no great benefit from using them in road races / time trials. I'd be interested in hearing your thoughts.

Cee-Jay-Cee

I have 175mm cranks on my MTB and find them better than the 172.5 cranks on my road bikes. Maybe its my imagination but I think I can get more leverage with the longer crank and find climbing out of the saddle easier on the longer cranks however in my case its very difficult to properly compare as the bikes are vastly different. I cant see any benefit to shorter cranks, especially if you consider yourself a spinner rather than a grinder.

StevieGriff

Cee-Jay-Cee wrote: »

I have 175mm cranks on my MTB and find them better than the 172.5 cranks on my road bikes. Maybe its my imagination but I think I can get more leverage with the longer crank and find climbing out of the saddle easier on the longer cranks however in my case its very difficult to properly compare as the bikes are vastly different. I cant see any benefit to shorter cranks, especially if you consider yourself a spinner rather than a grinder.

Here's a fairly good summary by Cervelo of a study done on crank length a few years back. Interesting stuff, basically surmises that comfort and practically is the most important factor.

Weepsie

This is Chris Boardman's take on it all

“I don’t think anybody’s really messed around with crank length yet because we’re constrained by history. I’d like to see a lot of people using 150mm cranks. All of the physiology data I’ve ever seen says that for an endurance athlete crank length actually doesn’t make any difference. But shorter cranks mean you’re more aerodynamic – if you’re trying to get into a tuck you can get lower because your knees aren’t coming up. So shorter cranks could produce a really big net gain but it’s a fashion thing.”

Weepsie

If you have about €1000 you can also buy the Look Zed crankset which lets you change the length to one of 3 options.

fat bloke

Weepsie wrote: »

If you have about €1000 you can also buy the Look Zed crankset which lets you change the length to one of 3 options.

Cripes you'd buy three dura ace cranks for a grand though.

I messed around with 165's last year after years on 172.5 & to be honest noticed absolutely no difference whatsoever.

gaffmaster

I'm 169cm tall and online fit calculators (like this Zinn one) say I should have 161mm cranks.

I'm currently running 170's on both of my road bikes. I get lower back pain and tight hip flexors. I have read that shorter cranks can help alleviate these issues as you're not making the angle of your hips quite as acute at the top of the pedal stroke. I've yet to be able to afford the upgrade to 165's. A club-mate of mine who's exactly the same height as me has 165's on his track bike and finds them a lot more comfortable.

Any extra leverage a larger lever would give you, I'd imagine might be lost if your muscles have been positioned beyond their most powerful range of motion. In other words, a bigger dead-spot at the top of the rotation? That's just my interpretation, and could be wrong.

OP - when you changed to 165 cranks, did you raise your saddle by 5mm? You might also need to move it back a touch as well depending on seat-tube angle. This should help reduce that acute angle even further, as well as make you more aero = double win!

fat bloke

gaffmaster wrote: »

. I've yet to be able to afford the upgrade to 165's.

I just went with cheapy tiagra 165's for the experiment. 70 quid online.
Still use em on the turbo.

gaffmaster

fat bloke wrote: »

I just went with cheapy tiagra 165's for the experiment. 70 quid online.
Still use em on the turbo.

Not a bad idea. I actually got a free set of 165 Gossamers but they're BB30 and won't fit my bikes!

Shoco83

I switched to 165 on both my bikes after getting a bike fit. The main reason for the recommendation was the tight hips, so as mentioned above the hip angle doesn't close as much as the 12 o'clock position, I think my cadence has also increased as a result of the change. If I'm honest I don't find a massive difference between them and what was 170mm

I do have a third bike that I keep on the turbo with 170 cranks, and on occasions I have felt a bit of discomfort in the hip if really pushing it, so I guess there is a benefit to the change

Classyrider

OP - when you changed to 165 cranks, did you raise your saddle by 5mm? You might also need to move it back a touch as well depending on seat-tube angle. This should help reduce that acute angle even further, as well as make you more aero = double win!

Yes i made the adjustments with the shorter cranks after my bike fit...they did not suit at all. They feel wrong.

NeedMoreGears

I am also 165cm and had to replace cranks recently. I went for 165mm tiagras instead of the 170mm that I had been using. I raised the seat 5mm to compensate. I can't say I've noticed any difference at all, even in the small ring/biggest gear combo where the small loss of leverage cannot be compensated by gear selection.

DKmac

Adam Hansen of Lotto Soudal uses 180mm cranks on the advice of a mechanical engineer.

http://pelotonmagazine.com/travel-culture/from-inside-peloton-adam-hansen/