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  1. #1
    Senior Member deepakvrao's Avatar
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    Chainring and crankset questions

    Hi Guys,

    Wife and I have Bike Fridays with a

    Cranks - Alloy triple 170mm 30/42/52 130/74 bcd 119mm

    Big chainring sometimes gets damaged in transit, so was thinking of carrying a spare.

    Couple of questions:

    1. Will I need to raise the FD if I put in a 53 instead of a 52?

    2. When I see online, I see 52T chainrings in the same BCD [130] as 'double' and 'triples'. What's the difference?

    http://www.chainreactioncycles.com/M...?ModelID=34733

    http://www.chainreactioncycles.com/M...?ModelID=34734

    3. Currently bikes are 8 speed, so can I put in a 9 speed or 10 speed chainring?

    Really appreciate any help here.

  2. #2
    coprolite fietsbob's Avatar
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    1t adds to the circumference & so to the diameter, so perhaps, yes..
    what is the difference? 1/2 inch.. the pitch between chain pin centers.
    the chainring tooth has to be cut thinner for a 10 speed chain,
    so ever-so slightly less surface to share the wear load of the chain..

    you can add one of bike Friday's big chainguard discs to a triple
    adding a spacer outside the outer chainring..

    I have a chainguard outside the outer chain ring on a touring bike,
    and a chain minder to catch over-shifts on the inside..
    So ... no missed FD shifts.
    Last edited by fietsbob; 07-10-12 at 11:54 PM.

  3. #3
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    1. Yes , you will have to raise the fd if it is currently close enough to the 52T ring. A 52T ring has a diameter of 8.28" and a 53T is 8.44" so the radial difference is .08" or about 5/64".
    2. A "triple" middle chainring has ramps and pins on it's inside face to assist the shift from the granny ring to the middle. A double inner ring does not need these shifting assists on it's inner face.
    3. If you use 9 or 10-speed chainrings with an 8-speed chain, the probability is the chain will rub on the outside ring when in the middle ring.

  4. #4
    Senior Member deepakvrao's Avatar
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    Quote Originally Posted by fietsbob View Post
    1/2 inch.. the pitch between chain pin centers.
    the chainring tooth has to be cut thinner for a 10 speed chain,
    so ever-so slightly less surface to share the wear load of the chain..
    So, will it really make a practical difference? I am able to find mostly 10 speed chain rings online.

    Quote Originally Posted by HillRider View Post
    1. Yes , you will have to raise the fd if it is currently close enough to the 52T ring. A 52T ring has a diameter of 8.28" and a 53T is 8.44" so the radial difference is .08" or about 5/64".
    2. A "triple" middle chainring has ramps and pins on it's inside face to assist the shift from the granny ring to the middle. A double inner ring does not need these shifting assists on it's inner face.
    3. If you use 9 or 10-speed chainrings with an 8-speed chain, the probability is the chain will rub on the outside ring when in the middle ring.
    Ponts 2 & 3 - any effect if it is the biggest chainring that I change? I see even the 52t chainrings labelled as double/triple [links given in original post].

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