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  1. #1
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    Shorter cranks on more aggressive rig?

    8 Hours Ago
    Could anybody help me make up my mind on going for shorter cranks on an AM/Enduro style bike? Im in need of a new ring, cassette, and BB so now would be the time to do it. Ive always ridden 175s on everything, Im 61 with about 34 inseam. I am currently running the 175 cranks from my old bike which had a higher BB than what I am on now (12.4mm drop, 27.5, hefty sag).

    The advantage for pedal clearance is obvious, I scrape and catch my pedals more now and have to watch my timing more but Im managing. Im running platform pedals and tend to mash when Im trying to keep the pace up so Im a little afraid of losing torque / power to mash climbs and sprints. Does anyone think shorter helps any for control on jumps, manualing, technical terrain or hinders? It seems like longer might actually give more stability for handling since your legs are spread a touch more but I have heard the opposite can be true? I realize were talking a tiny change but Im looking for opinions... 170, 165, or ride what I got? Thanks for any insight.

  2. #2
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    I recently went from 175 to 170 - primarily because all the new bikes have such low bottom brackets. Pedal strikes improved, and honestly, I find the 170s far more comfortable. I can't tell a difference on power in the slightest, I even think it's maybe more efficient - I do for sure notice my knees like the 170s better.

    I'm basically the same height as you, tempted to throw a 165 on next and test that on a Fuel EX.

    Walt posted some of his experiences with short cranks in the plus forum where he had positive results. However, a few people will invariably argue you lose power. Honestly it boils down to personal preference. In my experience, it's been a huge improvement.

  3. #3
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    I run a 170 on my FS rig and a 175 on my SS. I think the biggest thing I notice is that I don't notice really any difference. More importantly, I have not experienced any negatives with the shorter crank arm. I'm 5'8" so that may factor into it a little FWIW.

  4. #4
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    I am 6' and just put some 165 on my bike to gain pedal clearance. I cannot tell the difference from the 175 it replaced.


  5. #5
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    The taller you are, the less it matters I think.

    You mechanically already "fit" a 175mm crank. Im 5'7, I dont fit a 175mm crank. Even with 170's my knees sometimes end up at a weird angle that I cant apply power at.

    Ill admit that even at 5'7 the stallout feeling I get is pretty rare. Riding the same trail, I'll hit that weird stall out on only one section, and maybe once every 3rd or 4th ride. Id benefit from 165's I think.

  6. #6
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    Quote Originally Posted by One Pivot View Post
    The taller you are, the less it matters I think.

    You mechanically already "fit" a 175mm crank. Im 5'7, I dont fit a 175mm crank. Even with 170's my knees sometimes end up at a weird angle that I cant apply power at.

    Ill admit that even at 5'7 the stallout feeling I get is pretty rare. Riding the same trail, I'll hit that weird stall out on only one section, and maybe once every 3rd or 4th ride. Id benefit from 165's I think.
    An oval ring would help you with that stallout feeling you are getting as well

  7. #7
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    True, but I wonder if ovals are working around a crank length issue! I'll eventually try an oval, but I know stepping down a crank size would be a good move too.

    There's a ton of road focused articles on this, but mtb is finally coming around too.

  8. #8
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    I'm 6'1" and I recently put 165mm cranks on my Stache. I absolutely think that it was one of the best purchases I've made. I wrote my thoughts about them here. Paradigm Drift, or OMG, I built myself a bike!
    Change begins by doing something different.

  9. #9
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    5'4" here on a 2017 Fuel EX-8 27.5+. Went from the stock 175 cranks to 165 cranks. The best upgrade I did to my bike bar none. Pedal strikes are now the exception. I also went with 32T oval. Also, I noticed a smoother cadence on my climbing.

  10. #10
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    Quote Originally Posted by One Pivot View Post
    True, but I wonder if ovals are working around a crank length issue! I'll eventually try an oval, but I know stepping down a crank size would be a good move too.

    There's a ton of road focused articles on this, but mtb is finally coming around too.
    I'm 5'6" 165mm cranks with an oval, I may go to 160s I feel the oval more on tech climbs but it didn't solve the hitch at the top of too long of a crank when I ran 170s

  11. #11
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    Thanks for the discussion. I nearly ordered 165mm cranks but decided to compromise on 170mm for now and see how that goes. I didn't want to give up any seat clearance or change bar height, I feel like everything is fairly dialed as it is. I'm sure 170 won't be much of a change but I'm betting I'll like it.

  12. #12
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    I'm at the absolute minimum size with my new bike and 165s cranks. It's a 29er and I smash my taco all the time. Had I went with longer cranks (not recommended by bike company) I would've had to reduce the dropper stroke to fit.

  13. #13
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    Quote Originally Posted by One Pivot View Post
    The taller you are, the less it matters I think.

    You mechanically already "fit" a 175mm crank. Im 5'7, I dont fit a 175mm crank. Even with 170's my knees sometimes end up at a weird angle that I cant apply power at.
    This is true. A 6' 1" person can run just about any crank length. But the standard 175mm cranks are too big for lots of people. Sizing down isn't a big deal. Sizing up has disadvantages.

    The one advantage of having a shorter crank is being able to get a better hinge in attack position, or at least not needing quite as much flexibility. The farther your feet are in attack position, the more flexibility you need in your hamstrings to get the ideal position.

  14. #14
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    Quote Originally Posted by trailsnales View Post
    I realize were talking a tiny change but Im looking for opinions... 170, 165, or ride what I got? Thanks for any insight.
    I've gone from 175mm cranks to 170mm cranks and back to 175mm cranks on three different bikes. The middle one had a lower BB hence the desire for shorter cranks. Within this ^^ limited range of length I did not notice any significant difference.
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  15. #15
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    I'm 5'6'', ride a 27.5 trail bike and low BBs are great but do have their downsides. My knees are also pretty rough so 165mm cranks work great for me and I almost never have pedal strikes unless it's really techy climbing and I'm not in a spot to ratchet. I do not find climbing to be any more of an effort. All pros and no cons in my book.
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