help: road cranks vs MTB cranks??- Mtbr.com
Results 1 to 12 of 12
  1. #1
    likes beer
    Reputation: manida's Avatar
    Join Date
    Feb 2008
    Posts
    345

    help: road cranks vs MTB cranks??

    so, for a while now my drive-side crank arm has been hitting my chainstay when I pedal...just barely. Ive covered the chainstay in hockey tape and it is now just rubbing the tape, but not all the way through to the paint, fortunately.

    So, I took it to my LBS and they told me that I had road cranks (175mm Mavic) on it and that was the reason it was hitting my frame. I asked if I could just get a new (longer) bottom broacket and they told me that my BB was 130mm and they dont even make them that long anymore. They told me that MTB cranks would fix the problem.

    Now, whats the diffference between road and mtb cranks??

    Thoughts on solving my issue?

  2. #2
    one chain loop
    Reputation: fishcreek's Avatar
    Join Date
    Apr 2007
    Posts
    2,360
    dremel the crank arms which is touching the stays, i shaved around 3mm and rode like a dream.
    everything sucks but my vacuum cleaner.

  3. #3
    likes beer
    Reputation: manida's Avatar
    Join Date
    Feb 2008
    Posts
    345
    thats a good idea! But still, whats the difference between road cranks and MTB cranks?

  4. #4
    mtbr member
    Reputation:
    Join Date
    May 2006
    Posts
    23
    More curve on the crank to put the pedal further out to clear wider stays?

  5. #5
    Not a regular
    Reputation:
    Join Date
    Jan 2004
    Posts
    4,079
    The differences are road cranks are generally lighter weight, have larger bolt circle diameters (130mm for Shimano), are double rings, and generally require a narrower bottom bracket axle. Road chainline is roughly 45mm. Mountain bike chainline is roughly 47-50mm. This is based on road rear hub spacing of 130mm and mountain bike hub spacing of 135mm.

    Okay, there are road triples and road compact (with 110mm bolt circle). Mavic cranks (if they are indeed road cranks that I'm thinking of) don't do well on frames with widish chainstays because of the crank profile.

    There's plenty of folks who use road cranks on their mountain bikes. You just need to be prepared to do some modification to make them work sometimes. And taking a dremel or file to the inside edge of the end of the crank to knock off a corner is fine to get clearance.

    Can you post a picture of your drivetrain (crank and clearance)?

    (edit: I see your MB-1 in your profile picture - is that the bike and crank? What size ring is on there? Are there threaded holes on the backside of the arm to mount a triple ring?)

  6. #6
    Keep on Rockin...
    Reputation: Miker J's Avatar
    Join Date
    Nov 2003
    Posts
    5,929

    Road cranks...

    I prefer the one set of road cranks that I have (TA Carminas) to my MTB cranks. They give a much narrower Q (which my frame's chainstays allow). I find a narrow Q induces less lateral flex on the frame's BB area, and it feels nicer to pedal.

  7. #7
    rider
    Reputation:
    Join Date
    Feb 2008
    Posts
    217
    road bikes have narrower stays. (130 mm dropouts vs 135 for mtb's and skiny tires) so, they move the road cranks as far in as they can, (which is more efficient.) we mountain bikers sacrifice a little pedaling efficiency and take the wider cranks, and we get beautiful wide knoby tires because of it.

  8. #8
    likes beer
    Reputation: manida's Avatar
    Join Date
    Feb 2008
    Posts
    345
    sorry, Im not able to post a pic....

    but what about BMX cranks? Do you guys think I'll run into the same problem that Im having with road cranks? Do they curve "inwards" like my road cranks? Or are they more like MTB cranks?
    (my bike has a BMX stem and BMX cruiser bars...so Im going that route anyway)

  9. #9
    likes beer
    Reputation: manida's Avatar
    Join Date
    Feb 2008
    Posts
    345

  10. #10
    mtbr member
    Reputation: Treybiker's Avatar
    Join Date
    Jan 2004
    Posts
    1,041
    WTF??? The LONGEST those cranks come in is 155 mm (smallest is 135mm).

    Are you a Nome?

  11. #11
    likes beer
    Reputation: manida's Avatar
    Join Date
    Feb 2008
    Posts
    345
    scroll down bro, they come in 175 mm as well.


    and its spelled GNOME
    Last edited by manida; 04-23-2008 at 02:11 PM.

  12. #12
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    820
    Quote Originally Posted by manida
    scroll down bro, they come in 175 mm as well.


    and its spelled GNOME
    ROTFLMAO! No...he was wanting to know if you're from Nome, Alaska. They all use short, short cranks up there, the better to clear the mud, and to give a better chance to escape the bears.

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.