Results 1 to 8 of 8
  1. #1
    mtbr member
    Join Date
    Apr 2013

    Drivetrain Question


    ive bought a niner EMD Frame, i have transfered most of the parts from my 26", aside from wheels and forks,

    i have a question im sure has been answered but cant see it in the forum.

    " do 29 er wheels need a different sized cog system at front and rear to turn the bigger wheels, ?

    ive looked at what the manufacturers are turning out some have same sized cogs on 26 and 29, this cant be right , any experiences, ideas , arguments ?

    i race xc and the 29 is faster overall but slow on starts, i would appreciate any insight,


  2. #2
    1*14*29*2.1 & 1*1*29*2.4
    Join Date
    Nov 2009
    same gears, bigger legs

  3. #3
    R.I.P. DogFriend
    Reputation: jeffj's Avatar
    Join Date
    Jan 2004
    What drivetrain combo are you running (chainring and cassette sizes)?

    If you want, I'll run the gear inch numders and post them up, or you can do a search for an online gear inch calculator. I use 88.6" for the 29er circumference and 88.3 for 26" wheels (because that's what the rollout was on wheels I had).

  4. #4
    Reputation: evasive's Avatar
    Join Date
    Feb 2005
    No. Most people who claim they need smaller gearing are looking at the low end of their drivetrain, and if you're racing XC that's probably not your priority anyway. Give your existing drivetrain a try and see if it works for you. You can always spend the money to change down the road.

  5. #5
    mtbr member
    Reputation: kevocastro's Avatar
    Join Date
    Sep 2011
    Well, there's no such thing as 29er specific drivetrain but you can certainly benefit from a different setup than the one you might be running on your 26.

    For years we have been using 3x cranksets, in my 26 bikes I could get into the 44 big ring on flats and roll all the way, once I built my first 29 bike I went with 44/32/22 and 11/34 cassette, the thing is that I spent almost all the time on the 32 ring, the granny was way too granny and the 44 ring required tons of effort in anything it was not a flat.

    Then I moved to 2x10, 39/26 and 11/36 cassette and I don't miss any gear, the only thing is that you won't be able to hit 50 MPH at least it's a BIG hill
    Highball CC
    Ripley 1st Gen

  6. #6
    mtbr member
    Reputation: Gasp4Air's Avatar
    Join Date
    Jun 2009
    Short answer: No. There's no 29er-specific requirements for a drive train. As with a 26er, they can be set up any number of ways, ranging from single speed to 3 x 10, with various ring and cassette sizes, plus some 11 speed cassette options. There are more possibilities than ever.

    However, because a 29er wheel has a bigger circumference, one pedal rev moves you a bit further than on a similarly geared 26er. So that pedal rev is actually doing more work, and is a bit harder. The effect is roughly equivalent to losing your granny gear.

    There are 2 common ways to get granny back:

    The easiest way is to get a cassette with 36 tooth big cog. In 9-speed, there only one ready-made option, the Shimano HG-61, which good but a bit on the heavy side. In 10-speed, there are more 36t cog options available.

    The other way is to replace your 22t or 24t inner ring with a 20t ring. ActionTec makes one. Installing it will likely require some filing and fiddling, as this really pushes the boundaries of what will fit on a standard spider.

    Or, do both, and get a great-granny for crawling up steep chunk with rubbery legs.
    Use it, use it, use it while you still have it.

  7. #7
    mtbr member
    Join Date
    Apr 2013

    Thanks to all

    thanks for your time in replying i have decided to go with the following

    combination; a shimano 22- 36 chainset

    1 Shimano XT M771 10 Speed MTB Cassette - Each - 11-36

    would it be prudent to put a larger big ring at front, remember this is for xc racing,

  8. #8
    turtles make me hot
    Reputation: NYrr496's Avatar
    Join Date
    Sep 2008
    My Stumpjumper FSR originally came with the exact same drivetrain as my friend's 26er.
    I swore up and down I needed slightly different gearing.
    I swapped the cranks from 175 to 180, ditched the big ring and swapped the granny from 20 to 24. Now I have 32, 24 up front and I swapped the cassette from 11-34 to 11-36.
    I find the bike infinately more rideable and I use a wider range of the cassette.
    Just my findings.
    I like turtles

Similar Threads

  1. Drivetrain question
    By JerB in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 3
    Last Post: 07-31-2012, 04:46 PM
  2. Another drivetrain question- drivetrain noise
    By Streetdoctor in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 1
    Last Post: 03-20-2012, 01:50 PM
  3. DJ drivetrain question: SS to 1x9
    By dth656 in forum Urban/DJ/Park
    Replies: 5
    Last Post: 09-20-2011, 03:15 PM
  4. Drivetrain question. Please help.
    By igz in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 7
    Last Post: 09-04-2011, 04:07 AM
  5. Drivetrain Question.
    By k^2 in forum Santa Cruz
    Replies: 1
    Last Post: 04-27-2011, 04:27 PM

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



VISIT US AT and the ConsumerReview Network are business units of Invenda Corporation

(C) Copyright 1996-2018. All Rights Reserved.