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Front rotor size for 29er 180 vs 160mm

burglarboycieburglarboycie Posts: 200
edited June 2014 in MTB general
Hi all
I am going to upgrade the rotors on my 29er soon and was thinking about going from 180mm down to 160mm on the front.
What are peoples experience with this?
I certainly find that the 180mm that's on there at the moment is plenty powerful enough so can't really see the power dropping hugely by going smaller.


  • RockmonkeySCRockmonkeySC Posts: 15,247
    Biggest difference between rotor sizes is heat dissipation rather than power.
    On a pure xc bike I would use a 160mm rotor.
  • Depends how fat you are.

    160mm rotors don't stop me.
  • The RookieThe Rookie Posts: 27,748
    cyd190468 wrote:
    . It's standard practice when you put bigger rims on a car..
    Except on a car most people do the sensible thing and keep the rolling radius the same and use lower profile tyres to stop the speedo being useless (and illegal)......on cars it's more about fitting the bigger discs the wheels now allow you to fit (as they are inside the wheel unlike on bikes).

    I do agree 'most' 29ers use 180's to keep the leverage ratio about the same though.
  • GiraffotoGiraffoto Posts: 2,078
    180mm works nicely for me. If it works for you, why change? Does it lock up too easily? You'll save almost no weight, expend effort and possibly money, and it'll probably need bedding in again. Don't bother, in short
    Specialized Roubaix Elite 2015
    XM-057 rigid 29er
  • I weigh next to nothing so think I should be ok with a smaller one up front and will be buying a pair of new rotors soon regardless so think I might try going for a pair of 160s as the price is the same for both 180 and 160 for the rotors i'm looking at.
    I do find that the front has more bite than the rear and would like to even it up a bit
  • stubsstubs Posts: 5,001
    If your a lightweight and dont do long fast downhills then you will probably get away with a 160mm. I have a 180mm front on my 29er but I am a fat knacker so need all the power I can get.
    Fig rolls: proof that god loves cyclists and that she wants us to do another lap
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