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Crank Swap Help Needed

Dale_CannonDale_Cannon Posts: 7
edited September 2016 in MTB workshop & tech
Hi All,

I'm just about to buy a new 2016 Habit 4 and plan to upgrade the brakes, shifters and cranks to XT.

I'm a little stuck on the cranks though. I plan to buy the XT M785 cranks with double chain rings, the rings on the new XT crank are 24/38 but the cranks on the bike are Shimano Deore M617, 22/36.

I think the extra two teeth per chain ring should not be an issue but I would like someone with more knowledge to confirm that other than some slight adjustment, I should be good?

All feedback welcome.

Posts

  • whyamiherewhyamihere Posts: 7,679
    You'll need to raise the front mech slightly. The chain length will most likely be ok, but I'd check it (wrap the chain around the largest rear sprocket and the largest chainring without going through the rear mech, there should be a couple of links overlap). If it isn't, you'll just have to be careful not to go largest-largest, though you shouldn't do this anyway.
  • cooldadcooldad Posts: 32,599
    Any reason why? The stuff on the bike works fine.
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  • Dale_CannonDale_Cannon Posts: 7
    cooldad wrote:
    Any reason why? The stuff on the bike works fine.

    The bike gets great reviews in standard form but my son's new bike has Tektro brakes which are pretty censored so I'll stick my brakes on his and upgrade mine to XT.

    Whilst I'm there I'll do the shifters as they are pretty cheap, for the sake of a little more I'll upgrade the front and rear mech. The cranks are more of a nice to have and I like the black finish which complements the acid green and black color theme of the bike.

    All the bits I'm planning on taking off my bike should go on my son's bike which we'll all act as upgrades so nothing is going to waste.
  • The RookieThe Rookie Posts: 27,811
    As noted you may (or may not) need to raise the front mech a fraction and may (or may not) have to put an extra pair of links in the chain. Most OEM bikes are set up quite conservatively so it will probably be fine.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • Dale_CannonDale_Cannon Posts: 7
    The Rookie wrote:
    As noted you may (or may not) need to raise the front mech a fraction and may (or may not) have to put an extra pair of links in the chain. Most OEM bikes are set up quite conservatively so it will probably be fine.

    Many thanks - that's super-helpful.

    Will let you know how I get on.
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