Roadie crank length?- Mtbr.com
Results 1 to 11 of 11
  1. #1
    Retro Grouch
    Reputation: aka brad's Avatar
    Join Date
    Dec 2003
    Posts
    2,091

    Roadie crank length?

    Okay, I am a believer in long cranks on a MTB SS. My new Bonty only has 175's and, although a pleasure to ride, I can feel the difference when climbing. But what about fixie/SS road bikes. I converted my old Peugeot to a SS years ago and kept the cranks @ 175. My fixie has 166.5 cranks and the short crank arms don't seem to be a problem. I have noticed however that the shorter crank arms are easier to tun over and I get a better spin. I know that traditionally fixie crank arms are shorter for better ground clearance. The other consideration is, these days, most pro riders run 170-172.5. Also most of the graphs that show long legged riders need longer crank arms, also show your average 509-510 rider should be running 170. I recently picked up set of 170's for my Peugeot and will report back. Regardless, it would appear that in the US we are being sold a bill of goods with 175's being the industry standard OEM. What do you think?

    1G1G, Brad
    Just one more rep and I get the toaster!

  2. #2
    "Mr. Britannica"
    Reputation: roadiegonebad's Avatar
    Join Date
    Jan 2004
    Posts
    1,818
    what's the question???

  3. #3
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,023
    It doesn't really matter much. I agree longer arms do matter on SS mountain bikes but on the road it's pretty inconsequential. Long/short, fixie/SS, 172.5/180, doesn't really make much difference. Because you have to keep pedaling on a fixie it's possible to bang a pedal in a corner which can have some pretty unsettling consequences depending on your speed, how sharp the corner is, how much you're leaning the bike, etc. However, hitting a pedal is not that common on the road but I've done it. I tend to gravitate towards 172.5 on the road for my fixie and I usually run 175's on my geared road bike, it helps prevent pedal strike and I don't really notice the difference in cadence. Overall, though, it's not that big a deal.

  4. #4
    Retro Grouch
    Reputation: aka brad's Avatar
    Join Date
    Dec 2003
    Posts
    2,091

    two questions actually..

    Quote Originally Posted by roadiegonebad
    what's the question???
    1) Have we been hoodwinked into believing that 175mm is the best compromise for crank length?

    2)If 170-172.5 is a better length all around, would the fact that you are riding a fixie make any difference.

    Brad
    Just one more rep and I get the toaster!

  5. #5
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    9,618
    Quote Originally Posted by aka brad
    1) Have we been hoodwinked into believing that 175mm is the best compromise for crank length?
    Yes, no question about it. Why don't we all ride the same frame size?


    Quote Originally Posted by aka brad
    2)If 170-172.5 is a better length all around, would the fact that you are riding a fixie make any difference.
    Sorry, I don't ride fixed so I don't know.

    --Sparty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,023
    On a road bike crank length (within a reasonable range and certainly within the normal road bike ranges of 170-175) makes little difference. It's not at all like frame sizes when it comes to fit. Most people won't be able to tell the difference and there won't be much, if any difference, in ride times, power, speed, etc. There are tons of threads over on RBR on this topic and there have been studies and attempts to quantify the data and predict results. What it all comes down to is the differences just aren't enough to worry about. Go with what is comfortable to you or what you've got in the parts bin or what, psychologically you think gives you the "edge". But don't overthink it on the road. It's a bit more of an issue on SS mountain bikes because it's a whole different ride. Leverage means a lot.

  7. #7
    mtbr member
    Reputation: 2xPneu's Avatar
    Join Date
    Jan 2004
    Posts
    916
    I ride 165s on everything-road fixed, offroad fixed, and offroad geared.

    Lots fewer pedal strikes is a good thing on the fixie, and it also means I can continue to put power to the ground over rocks and roots, even on the geared bike.

    Don't notice, or have completely forgotten, any advantages to using longer cranks.

    I'm 6'1", 34" inseam.

  8. #8
    CB2
    CB2 is offline
    Jam Econo
    Reputation: CB2's Avatar
    Join Date
    May 2006
    Posts
    4,214
    Oddly enough, all my bikes have 170mm cranks except my roadie singlespeed, which has 172.5 mm cranks, and that because that's what I had lying around.

  9. #9
    mtbr member
    Reputation: FlatFender's Avatar
    Join Date
    Aug 2006
    Posts
    663
    Quote Originally Posted by aka brad
    1) Have we been hoodwinked into believing that 175mm is the best compromise for crank length?

    2)If 170-172.5 is a better length all around, would the fact that you are riding a fixie make any difference.

    Brad
    2. On a fixie, you must pedal through turns, so shorter cranks = less pedal strike.

  10. #10
    mudnthebloodnthebeer
    Reputation: quaffimodo's Avatar
    Join Date
    May 2004
    Posts
    585
    I agree that we tend to use what the bike industry makes available to us. Reading this forum several years back got me thinking outside the box about crank length. I did some research, talked it over with my Doc (a stud cyclist btw.) and invested in 200mm cranks for my SS. I'm 6'4 with an inseam a bit over 37", and for me the change was a revealation. I've gotten good enough at spinning them on the flats that I'm trying them on my road bike on rollers this winter. 180's just felt weird after being on the SS. It's a little cramped at the top of the stroke down on the drops and I'm not smooth enough for one-leg pedaling quite yet but I think that it's going to happen. Obviously this wouldn't work fixed.

  11. #11
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    9,618

    Right on, Brutha

    Quote Originally Posted by quaffimodo
    I agree that we tend to use what the bike industry makes available to us. Reading this forum several years back got me thinking outside the box about crank length. I did some research, talked it over with my Doc (a stud cyclist btw.) and invested in 200mm cranks for my SS. ....
    Right on, Quaffmeister.

    Even after 15 years of riding 195-202mm cranks I'm still a little surprised and a lot disappointed whenever I hear anyone say, "Crank length doesn't make much difference."

    Makes me think of the phrase, "You don't know what you don't know."

    It may be true that power output measured in horsepower is not much different, but the differences in leverage, comfort, torque, etc... these differences are real and substantial. Just ask the guys half my age who ride with me if they don't think I've got something goin' on. Long cranks are not for everybody, but if one has long legs...

    Likewise shorter cranks for those with shorter gams.

    I say, long live the notion of appropriately sized cranks. Just like big/small frames, wide/narrow handlebars, tall/short saddle height, and shoes that fit; why would anyone not think the same philosophy applies to crank length?

    I still don't know.

    --Sparty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

Members who have read this thread: 0

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.