Chainring help!

tomashford
tomashford Posts: 27
edited August 2008 in Workshop
I currently use a compact 50/34 chainset but would like to replace the 34t with a 39t. But when looking at the 50t chainring, it says to use with a 34t inner ring only. Why does it say this and does it really matter if I put a 39t chainring on?

Thanks

Tom

Comments

  • nmcgann
    nmcgann Posts: 1,780
    tomashford wrote:
    I currently use a compact 50/34 chainset but would like to replace the 34t with a 39t. But when looking at the 50t chainring, it says to use with a 34t inner ring only. Why does it say this and does it really matter if I put a 39t chainring on?

    Thanks

    Tom

    It's probably something to do with the positions of the shifting pins and profiled teeth on the 50T ring being designed to work best with a 34T inner ring.

    I'd be inclined to just try it and see how you get on. I use 38/50 on my summer road bike which I think is a great combination.

    Neil
    --
    "Because the cycling is pain. The cycling is soul crushing pain."
  • fizz
    fizz Posts: 483
    I'm not sure, but I dont know if you'll get a 39T chain ring that fits on a compact chain set. its 110BCD and you normally find 39T rings on a standard double wihich is 130 BCD.
  • tomashford
    tomashford Posts: 27
    Thank you for the replies. I think I will try the 39t and just see how it goes.

    fizz, I looked on wiggle and found that you can get a 39t which is 110BCD.

    http://www.wiggle.co.uk/p/Cycle/7/FSA_110_PCD_Compact_Road_Inner_Chainring/5360031665/
  • fizz
    fizz Posts: 483
    Cool

    You might also find it shifts better onto the inner chain ring as the jump between the two rings isnt as big. But you might have to fiddle with the height of your front mech to get it to work properly.

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