Crank length?

Offroader said:
*** snip ***
Is it even worth dropping from 165mm to 135mm? Seems like you guys like less than 100mm cranks.

30mm reduction is a lot more noticeable than you may think. My 15mm reduction clearly felt less stressfull than my 170mm cranks did, now I don't bonk my knee into my chest any more :) .
However, I would never advise anyone to go as low as 100mm cranks if your average height.
 
I would start with a reduction from 170-175 to 150mm. They are pretty cheap and standard. I had an immediate relief from knee pain with this reduction. You can always go shorter later. Remember that is an inch reduction! Really quite a bit.
otherDoc
 
Here is one and there are a bunch of others on Ebay.

http://www.ebay.com/itm/150-mm-SINZ-BMX-Alloy-Crankset-for-SquareTaper-cranks-110-mm-BCD-/371246957526?pt=LH_DefaultDomain_0&hash=item56700b03d6

otherDoc
 
Those bmx cranks aren't drilled out for a granny ring, i was hoping to find a short triple crank...? thanks
 
I think I am going to have my Shimano Zee hollowtech cranks shortened to 115 mm. I prefer to stick with my shimano cranks and hollow tech bottom bracket.

Someone already has their shimano zee cranks shortened to 135mm in the pictures and think you can lower it to about 115mm.

I have to decide if I want to try the job myself or send it out to someone to drill them.

I hardly ever pedal so this will be mostly for more comfort when standing up and down on the pedals. I always get slight pain in my right knee and am hoping that this may help.


974266d1426806107t-latest-build-commencal-supreme-20-full-suss-image.jpg
 
If you don't pedal, then there's no such thing as too short.

If you do pedal, and you have normal adult size legs, then 115mm is way too short.

You should consider manning up and legalizing your motorcycle, if that's what you have.
 
Chalo said:
If you don't pedal, then there's no such thing as too short.

If you do pedal, and you have normal adult size legs, then 115mm is way too short.

You should consider manning up and legalizing your motorcycle, if that's what you have.

I'm ordering a new Frame and am actually getting the removable foot peg option. Yes I agree with you about that, but I won't be legalizing it of course.

The cranks are in case I'm getting too much heat or trouble bringing my bike on the ferry boat into the city.
 
Gotta say, his assertion that a shorter crank could increase power is pretty specious. Drop 10% in crank length and you either have to turn them more than ten percent faster, push them more than ten percent harder, or a combination, before you make a single extra watt.

It's easier to see how you can make more power with a longer crank, up to the point where you get a range of motion issue. I know from using cranks in lots of lengths between 127mm and 225mm that longer is faster for me.
 
LockH said:

About the author:
Armed with degrees in exercise physiology and sports performance from a mecca of sports science, the Human Performance Lab at Ball State University, Mat Steinmetz settled in Boulder, Colo. “If you want to be in the thick of things in the endurance world, you have to go to where the best live and train,” he says. Steinmetz got his foot in the door of this world by working at Retül, where he began advising the likes of world champion Craig Alexander on bike fit.

Steinmetz had more to offer than tweaks to cycling position, as it turned out. Noticing that the world’s best triathletes didn’t receive the same level of attention that the elite cyclists did—in certain cases related to training, diet and technology, some were just “winging it”—Steinmetz began to offer more but through exceptionally small, concrete steps. As his work with athletes like Alexander, Julie Dibens and Tim O’Donnell grew in scope, he grew from status as a technical adviser into that of a coach. With his reputation for being data-driven and his skills in fine-tuned research, he began to get noticed in the pro ranks.

Continued success of the athletes Steinmetz is working with will undoubtedly propel him further in his mission to redefine the professionalism of coaching in triathlon. Through his new company, 51 SPEEDSHOP, Steinmetz offers his services as a consultant and coach to all ranks of athletes. In bike fits, wind tunnel testing, one-on-one consultations and clinics, the effect of his approach to the sport is widening.
 
Is that supposed to be an appeal to authority? Because if so, it's a poor one.

Another thing I've observed directly from decades in the bike shop environment is that triathletes are just about the biggest pack of idiots you could possibly select from the general public without visiting a special institution.
 
Chalo said:
Is that supposed to be an appeal to authority? Because if so, it's a poor one.

Hehe... My bad. OP in this thread asked "What size cranks is everyone using to have pedaling ground clearance?" but Mat/Physio Guy was actually writing about "exercise physiology and sports performance" of the human body.

Sorry. :)
 
Since he's a sport racing guy, I'd expect the part about short cranks allowing a lower, more aerodynamic position to trump pretty much any other factor. But that's different than allowing greater power output. It's like when velomobile guys use baby cranks to crowd their feet into a smaller space for lower drag. For them, the benefits might outweigh the tradeoffs.

In this thread, the point seems to be more about using donut wheels on bikes that weren't made for them. If you don't pedal (or even if you pedal just to create an impression), then what does it matter how long the cranks are? Any size will do, whatever fits.
 
Does anyone know if a set of unicycle crank arms include one l/h and one r/h threaded pedal hole? I pedal/move my feet only to activate the PAS and a set of 140mm cranks would be great going downhill while standing up.
 
WoodlandHills said:
Does anyone know if a set of unicycle crank arms include one l/h and one r/h threaded pedal hole? I pedal/move my feet only to activate the PAS and a set of 140mm cranks would be great going downhill while standing up.

Yes, uni cranks are threaded for RH/LH pedals. That's the only thing that distinguishes a right crank from a left crank.
 
Thanks, that opens up all sorts of options.

For anyone wanting to experiment with short crank arms there are some here for $15 a pair:

http://unicycle.shopgate.com/category/313735?page=1&sort=price_asc&settings=%7B%7D

They may be steel, but they are a cheap way to find out if they work for you. I am thinking that a pair of 89mm(!!) cranks would be just the thing for ultralite electric motorcycles. At that price, I could get a couple of different lengths to try out and if one size works get a set in alloy for a bit more money.
 
These are my thoughts on crank length, and I must add that I don't pedal because when I do I get pain in my right knee.

It seems to be understood that if you have a bad knee then shorter cranks help. This makes me believe that even if you don't have a bad knee you are still going to stress your knee by pedaling.

Since we have electric bikes after all, why bother with long crank lengths, why put extra stress on your knees. Maybe you won't ever have trouble, but maybe you will.
 
Back
Top