Do I need to shorter chain to go from 44T to 34T on SRAM 1x11

ronnierocket
ronnierocket Posts: 172
edited January 2019 in Workshop
I(bike shop) changed my cyclocross bike to a road set up to get more use of it in the summer and now want to put it back for a cyclecross race. It originally had a 34T and now has 44T, do I need to shorten the chain to go back to 34T or can I just swap over.

Comments

  • arlowood
    arlowood Posts: 2,561
    ronnierocket wrote:
    I(bike shop) changed my cyclocross bike to a road set up to get more use of it in the summer and now want to put it back for a cyclecross race. It originally had a 34T and now has 44T, do I need to shorten the chain to go back to 34T or can I just swap over.


    Yep pretty sure with that number of teeth difference you will need a shorter chain.

    I use this for calculating the correct chain length

    http://www.machinehead-software.co.uk/b ... hcalc.html


    I'm assuming you are talking about the front chainring sizes.

    Just input the largest rear cog and your 34t front chainring and the chainstay length and it will give you the answer. A rough check suggests the chain would need to be as much as 3 inches shorter to accommodate the 34t chairing
  • Mad_Malx
    Mad_Malx Posts: 5,002
    Depends on your derailleur. 10 tooth change would be no problem on a 2x.
  • The Rookie
    The Rookie Posts: 27,812
    Yes, as the chainwheel is 10t smaller, the 180 degree wrap has reduced by 5 teeth, so you need to remove either 2 or 3 pairs of links depending on how it was sized before.
    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.
  • cougie
    cougie Posts: 22,512
    Try it and see? It's pretty easy to shorten a chain (which I think you'd need to do anyway)
  • 6wheels
    6wheels Posts: 411
    Blimey cougie, you were up late/early!

    I always run my chains loose, making sure the top jockey doesn't touch the chain on the 11t sprocket.
  • lesfirth
    lesfirth Posts: 1,382
    cougie wrote:
    Try it and see? It's pretty easy to shorten a chain (which I think you'd need to do anyway)

    The first sensible answer there has been.

    The OPs question is like asking if the piece of string in my pocket will tie up my parcel. If we knew the length of his chain now, cassette size, chain wrap of the rear mech and length of his chain stays. He might get an answer worth having.
  • sungod
    sungod Posts: 16,532
    will you refit the 44t later on?

    if so...

    remove current chain and get a connex/similar reusable link for it (assuming the chain isn't sufficiently worn to need replacing)

    get a new chain (and a reusable link), fit the 34t, cut the chain to length as instructed in the instructions for the rear mech

    you now have two chains, each the correct length for their respective chainring, easy to swap in future
    my bike - faster than god's and twice as shiny

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