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Changing Gear Ratios and Chain

dawebbodawebbo Posts: 456
edited October 2009 in Road general
I've just ordered my first single speed bike for the winter, a Genesis Day One Cross. The set up on it is 42/18 - which is going to be a bit too short for what I'm going to be using it for. Will probably want something closer to 70".

Was thinking I'd be looking for something like 48/17 or 42/15.

My questions:
Will I need to adjust the chain for this? And if so, is it as simple as adding or removing links?
Do people change their setups often, justifying buying the tools to DIY, or would getting a LBS to do it be fine?

Thanks

Posts

  • WooliferkinsWooliferkins Posts: 2,060
    Once you have done the change just adjust the length of your chain to fit. You may find there is enough scope for adjustment within the sliding dropouts. Chain tugs make this fairly easy.
    Neil
    Help I'm Being Oppressed
  • stickmanstickman Posts: 791
    You'll only need a chain tool, which any cyclist should own anyway, and a spanner if it's nutted axle.

    Do you know the weight of this bike? Or can you let us know when you get it?
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  • owenlarsowenlars Posts: 719
    48:18 seems to be a popular way of getting 71". Also it is considered better to use even numbers of teeth on drive components as discussed by Sheldon Brown here.

    http://sheldonbrown.com/chain-life.html
  • dawebbodawebbo Posts: 456
    This is a link to the bike

    http://www.genesisbikes.co.uk/bikes/cro ... /overview/

    I have a chain link remover.

    I'm not familiar with the "goldie lookin'" chain which it comes with; assume it's just a standard 1/8", can one easily buy spare links for something like this? As if I put a 48T chainring on I'd imagine I'll need a few extra links.

    Thanks
  • Might have to remove a link or 2. Might not.

    Generally, if you are going from 42 x 18 to 42 x 15 then you will have 3 fewer teeth and so the axle will sit around 1 link's length further back in the dropouts.

    Buy a chain tool. You'll need one as a cyclist (as well as needing to know how to use it)

    You'll need a tool to remove the sprocket lock ring as well, if you want to fiddle around with changing one.

    Be careful about the gear ratios you plan.
    I run 42 x 16 and it's perfect for my flattish commute- I can spin to 23mph comfortably and up to 30 down hill before cadence gets too much.
    Commute: Langster -Singlecross - Brompton S2-LX

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  • dawebbodawebbo Posts: 456
    Makes sense.

    I was basing the ratio on the kind of speed I'd typically ride on my road bike and the ratios that other people in my cycling club use.

    I ride quite a high cadence, so if you find low 20s comfortable in 42/16 that might be a good starting point. I expect I'll only be using this for commuting, so happy to spin out at 30.

    Have a chain tool already, but never invested in a chain whip or lock ring as I've never had to take my free wheel off.
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