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How long is your crank?
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Author:  Dirtrider [ Sat Jul 07, 2018 2:52 pm ]
Post subject:  How long is your crank?

No, I'm not asking for your dick pics or tinder photos here. Sorry to let some of you down :)

Talking about crankset arm length. Seems like most are running 175MM and was just wondering if anyone has tried other lengths and what was the outcome. Is this even considered during a bike fitting?
I've got short legs and have pedal strikes on occasion and was thinking what the difference would be running 170MM. I'm guessing less leverage but looking for your input.

Cold beer makes the mind wander :cheers:

Author:  ajdonner [ Sat Jul 07, 2018 5:00 pm ]
Post subject:  Re: How long is your crank?

Short opinion: If you have the coin, get some short cranks and see if you like 'em. Otherwise, if you're not having knee/lower back/other pain I wouldn't bother changing your crank length; save your money and time your pedal strokes better. :wink: 5 mm is pretty small when considering pedal strikes but can be huge with regard to bike fit. Saddle position and knee pain.

Background: I run 172.5 mm cranks on my road bike as I have relatively short upper legs (and right leg is slightly shorter than the left so I have shims in between my cleat and shoe on my right) compared to my overall leg length. Before this setup I had left knee pain on rides over 2 hours as I was shifting to the right, to compensate for my shorter right leg, and stressing the left leg. Had a 'proper' road bike fit when I was doing centuries and triathlons and found all this out.

Have had 175 mm cranks on my mtbs (no cleat shims) and never had any issues on rides of 4 hours recently (9+ hours in my youth).

Author:  avidtest [ Sat Jul 07, 2018 8:06 pm ]
Post subject:  Re: How long is your crank?

Dirtrider wrote:
No, I'm not asking for your dick pics or tinder photos here. :cheers:



Ooops..... Go ahead and just delete the contents of your PM inbox!


I've had 170mm for coming up on 3 years now (my selection ostensibly due to lower BB height). I love 'em. Had 175mm on the last bike. Prefer my 170's. Way fewer pedal strikes (extra confidence and less thought required) and quicker, but less intense spin cycle. EveryBODY is different, but I'd think 170's would be an improvement for you. Increased cost for diminished returns? Possibly. Incorporate into next new bike?... :o

Author:  OhNooo [ Sun Jul 08, 2018 9:05 am ]
Post subject:  Re: How long is your crank?

I rode 180 cranks for the last 10 years. I’m a tall guy on an XL 29er, so they made sense.

Recently I switched from 2x9 to 1x11. Needed to drop to 28t chainring because of weak old chicken legs. The Race Face cranks were only in 175mm, so got those. I can’t tell the difference to be honest. I’m not sure it matters all that much.

Author:  ajdonner [ Sun Jul 08, 2018 9:06 am ]
Post subject:  Re: How long is your crank?

^^^ avidtest

Huh, imagine that. Never thought you'd be on 170 mm cranks.

Always thought of crank length in relation to 'fit' rather than pedal clearance. And that fit was more 'loose'/less of an issue on a mtb than road bike.

Author:  k2rider [ Sun Jul 08, 2018 7:41 pm ]
Post subject:  Re: How long is your crank?

I have 175 and 170 on different bikes. I can't tell a single bit of difference other than I have less pedal strikes on the 170's.

Author:  Dirtrider [ Sun Jul 08, 2018 8:29 pm ]
Post subject:  Re: How long is your crank?

I was wondering if anyone could tell the difference. We're only talking 5 mm here.

Author:  Kimba [ Mon Jul 09, 2018 10:30 am ]
Post subject:  Re: How long is your crank?

Got a 170 crank on the road bike and I noticed a difference from the 175 on the other one. The difference being it was easier to push harder on the smaller cranks. Basically, it didn't hurt as much over time. On a mtb, I would have to guess it would have the same effect.

Author:  Dirtrider [ Mon Jul 09, 2018 10:46 am ]
Post subject:  Re: How long is your crank?

Kimba wrote:
Got a 170 crank on the road bike and I noticed a difference from the 175 on the other one. The difference being it was easier to push harder on the smaller cranks. Basically, it didn't hurt as much over time. On a mtb, I would have to guess it would have the same effect.


Interesting that you thought the shorter length was easier since it would have a slightly shorter "leverage"

Author:  Inconceivable [ Mon Jul 09, 2018 10:50 am ]
Post subject:  Re: How long is your crank?

I started out with 175mm cranks on my bike but was experiencing quite a bit of pedal strike. Switching to 170 mm cranks seems to have made a significant improvement with respect to pedal strike. I haven't noticed much of a difference in pedaling effort as a result of the change in crank length, but I did change out a bunch of stuff (including drivetrain, wheels and tires) all at the same time, so too much changed at once for me to determine that.

Overall, I'm glad I switched to the shorter cranks.

Author:  Kimba [ Mon Jul 09, 2018 12:39 pm ]
Post subject:  Re: How long is your crank?

Dirtrider wrote:
Kimba wrote:
Got a 170 crank on the road bike and I noticed a difference from the 175 on the other one. The difference being it was easier to push harder on the smaller cranks. Basically, it didn't hurt as much over time. On a mtb, I would have to guess it would have the same effect.


Interesting that you thought the shorter length was easier since it would have a slightly shorter "leverage"


I think the easier feeling comes from smaller circles, but not sure.

Author:  Dirtrider [ Mon Jul 09, 2018 12:55 pm ]
Post subject:  Re: How long is your crank?

Just checking one web site for 11 speed Shimano cranksets with 170MM and it came up empty for MTB

Author:  Dirtrider [ Mon Jul 09, 2018 1:01 pm ]
Post subject:  Re: How long is your crank?

Just found a couple and seems like the higher gear ratios use shorter arms and the lower ratios had longer arms

Author:  Inconceivable [ Mon Jul 09, 2018 5:41 pm ]
Post subject:  Re: How long is your crank?

Dirtrider wrote:
Just checking one web site for 11 speed Shimano cranksets with 170MM and it came up empty for MTB


Are you saying that you're having a hard time finding a 170mm crank which will work with a Shimano 11 speed drive train? If it helps, I'm running XT 170mm cranks with M8000 XT 1x11 setup. Should be easy to find the parts.

Author:  Ld00d [ Mon Jul 09, 2018 6:03 pm ]
Post subject:  Re: How long is your crank?

Inconceivable wrote:
Dirtrider wrote:
Just checking one web site for 11 speed Shimano cranksets with 170MM and it came up empty for MTB


Are you saying that you're having a hard time finding a 170mm crank which will work with a Shimano 11 speed drive train? If it helps, I'm running XT 170mm cranks with M8000 XT 1x11 setup. Should be easy to find the parts.


So he should break into your garage, and he will find them there.

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