# An experiment: shorter cranks. Anyone else rocking them?



## Guest (Mar 7, 2015)

I've been riding for 20+ years, and for the past few years, I've started to feel really old. My hips hurt after riding, and it's been hard to figure out what the problem is.

Nothing is more awakening than doing deadlifts (yes, correctly, yes with a light weight, yes, with a trainer watching), and end up the next day unable to move because you pulled something in your hip.

So this got me thinking, so I asked Lee McCormack who I had training session with about crank length (Lee Likes Bikes), and it seems like a good thing to try.

In my entire time of riding, this is the first time I really took a true inseam measurement I gave Lee a round number of 28.5in, which is not accurate. After measuring correctly, I measure 29.75 to 30in in my inseam, which puts me at 165mm cranks.

Since I'm tired of going to PT for my hip, I'm going to try the 165mm cranks. I used to run 170mm, but I was running harder gears then too (36-24 with an 11-34 cassette, compared to the spinny 32-22 with an 11-36 I'm running now).

Has anyone (particularly woman, I'm sure men have different experiences) here gone to shorter cranks and noticed any particular differences, particularly with any hip or back or knee pain? Also, what differences does it make in your riding? I've heard that it can change cornering, clearance (that's a big duh though), and pedaling feels harder.

Thanks!


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## formica (Jul 4, 2004)

Stripes, I can't comment on crank length but I have had some definite hip pain issues that were resolved through various things. That is a different thread maybe. ?


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## supersedona (Dec 17, 2012)

I used to run 175mm in high school and college when I was doing speed commutes on the mtb and racing, but now 170 feels more natural. 31in inseam for me. 165 sounds like a reasonable shot but keep in mind your gearing should be compensated to reduce the loading since the leverage is lower. Spinning would likely be easier due to the reduced circumference however.


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## Melll (Jan 25, 2015)

I switched to 165mm cranks on my road and TT bikes in the fall, it's much more comfortable.

My fat bike came with 160mm cranks and I'm in love, I'd like the same for my mountain bike, but having a hard time finding anything shorter than 165


For reference: I round up to 5'2 and have a 27" inseam


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## ladljon (Nov 30, 2011)

Hi, I have been riding and racing for 30+yrs. I was riding 170mm and 167.5mm for years. Just recently went to 135mm on my MTB and CX bikes, and 125mm on my road bike. Absolutely love the shorter cranks. Check out Powercranks.com and give him a call. I tried the adjustable for two weeks and discovered which length was best for me. The machinist could only cut my 170 and 165 down to 135mm, but I bought the 125mm from power cranks.


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## supersedona (Dec 17, 2012)

That's cool! I didn't know about adjustible.


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## ladljon (Nov 30, 2011)

I had a machinist cut down my original cranks....$100 for two sets....There are other machinist out there who can do this procedure....


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## Melll (Jan 25, 2015)

Stripes said:


> Melli: Thanks, that helps a lot. I'm pretty sure I'm going to do the right thing by switching. Also, it's hard enough finding 165mm cranks. Only Shimano and Race Face Atlas seem to offer them as far as the mainstream.
> 
> I know that Lennard Zinn sells custom cranks as short as 130mm. Take a look here: Zinn Bicycle Crank Specifications | Zinn Cycles website and here: Zinn Cycles::custom bicycle cranks :: extra Long bike cranks :: short bicycle cranks | Zinn Cycles website


Thanks, I'll take a look at those 

The ones I have been eyeing up are the JR series from SunRace, what Specialized has on their junior-sized bikes (like my Fatboy). They come in 160 and are under $50


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## ladljon (Nov 30, 2011)

Also check out Bikesmith Design and Fabrication. He has short cranks. and can cut your cranks down.


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## girlonbike (Apr 24, 2008)

I'm so glad you brought this up, stripes. I'm kind of a bike geek and it always surprised me how little consumers know about bike fit and just hop on whatever somebody tells them fits until something starts hurting.

Crank length has been debated for decades as to how best to calculate it and the benefits of a shorter crank arm. Back in the dark ages, TA Specialites had them from 150 - 180, I believe. But for everybody else, 167.5 was about as short as they came.

For the people that like to do a little reading, Sheldon Brown wrote an article: Bicycle Cranks

Here's another article on calculating crank length: Bicycle Crank Length

Crank Length and Gearing - Slowtwitch.com that gets into some detail with gear ratios. It's speaking of tri riders but you get the gist.

And a few others including Lennard Zinn: Technical Q&A with Lennard Zinn: A question of crank length - VeloNews.com
CRANK LENGTH ? Which one? » Bike Fit » Steve Hogg's Bike Fitting Website
Peter White: How to Fit a Bicycle

Personally, I often find myself on 175mm cranks because I get used bikes. I quickly change them to 170mm on most of my bikes. I do have 167.5mm and 172mm cranks just to keep me on my toes and because I have a lot of bikes and I'm lazy. I can feel a noticeable difference between 170 and 175. I feel much better on the 170s for sure. I'm 5'4" and ideally, I should probably use something in the 16X range but I haven't looked around to make it work for me yet.


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## cleopatra999 (May 9, 2012)

Keep us posted on if this works for you! I have often thought of shorter cranks because I am very short through the inseam, just seemed to make sense to me. That and pedal bash. I wondered if it affected power though, levers and all that physics stuff.


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## jeffscott (May 10, 2006)

supersedona said:


> I used to run 175mm in high school and college when I was doing speed commutes on the mtb and racing, but now 170 feels more natural. 31in inseam for me. 165 sounds like a reasonable shot but keep in mind your gearing should be compensated to reduce the loading since the leverage is lower. Spinning would likely be easier due to the reduced circumference however.


Works the other way around short cranks need more force produce the same torque on the rear wheel.


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## ladljon (Nov 30, 2011)

the only difference I found between the short and long cranks: better breathing(knees not in my chest) better spin, easier to climb the steeps(smaller rotation) Leverage is not that significant between 120-170mm....maybe a tad while standing. Read the stats....Power Cranks.


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## LadyDi (Apr 17, 2005)

Great thread, thank you for posting! I had a total knee replacement last October. It was a little -no, make that a LOT!- more difficult to get back on the bike than anticipated due to stiffness, swelling, and scar tissue. I devoured Sheldon Brown on the crank length topic, then replaced my 29'ers stock 175mm cranks with 170's. Much better! I could easily have gone 165. Might yet. 

Another benefit to shorter cranks: fewer pedal strikes!


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## cyclelicious (Oct 7, 2008)

Glad the shorter cranks experiment worked out for you, Stripes


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## mtbxplorer (Dec 25, 2009)

Stripes said:


> Today was the first ride in them. Here's what I noticed that were somewhat expected:
> * No back or hip pain.


:thumbsup: Wow, I'm surprised it made such a difference! :rockon:


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