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Standard to compact

AnonymousAnonymous Posts: 79,667
edited April 2014 in Workshop
I'm sure this has been asked a million times, but I'm looking to change the standard double on my Carrera to a compact. The compact is coming off of an identical bike (another carrera). I'm going to get a bike shop to do the actual fitting but I'm wondering if anyone can advise me on somethings:

I've contacted various shops and have a different answer to this question:

Do I NEED to buy a new cassette, bottom bracket, and chain if I do this change?

I understand it might be preferable, but I can't afford it just now so will I be ok?


  • drlodgedrlodge Posts: 4,825
    The only thing you might need is a new chain, since your current one may not be long enough. For the cost of a new chain (which isn't much) I'd put a new one on anyway.
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  • bill57bill57 Posts: 454
    Unless I'm being really stupid, I would have thought the opposite - if you keep your existing cassette, and have smaller chainrings on the front, then your existing chain will need shortening by a couple of links.

    You can keep your bottom bracket if the new chainset fits it and gives the same chainline.
  • Omar LittleOmar Little Posts: 2,010
    Depends on what the chainset and bb is - are they the same apart from standard / compact?

    Im not exactly a skilled mechanic but changing crankset is relatively simple job to do, save a bit of money and do it youself then get a new chain with the money saved
  • AnonymousAnonymous Posts: 79,667
    It's the same just standard to double.

    I have a friend in the shop who will do it for cost of parts, which is why I'm going there. So new chain?
  • BozmanBozman Posts: 2,518
    Why would you need a longer chain if you're swapping from a standard to a compact, if anything surely you'll need to shorten your chain and drop your front derailleur a tad' and that's the lot.
  • bill57bill57 Posts: 454
    There is no need whatsoever to buy a new chain, assuming your present one is OK.
  • nochekmatenochekmate Posts: 3,460
    5min job!
  • gozzygozzy Posts: 640
    If you're keeping the same cassette and the big rings are the same size on the chainset, then all you need to do is swap the cranks, the chain will be fine.
    If it's the same length cranks you'll only need to swap the drive side too.
  • AnonymousAnonymous Posts: 79,667
    Great, thanks for your help, I'll let you know how I get on. Going to do it with him, so I know for future.
  • AnonymousAnonymous Posts: 79,667
    Thanks very much for the help. Great success, I'll be able to do this from now on.
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