standard to a compact

volvine
volvine Posts: 409
edited June 2009 in Road beginners
is it a simple/cheap job to change over from a standard shimano 105 to a compact????? :oops: :oops:

Comments

  • roger_merriman
    roger_merriman Posts: 6,165
    not terribly no, what cassette have you got? a cheaper way to lower the gearing is that.
  • You'll almost certainly have to shorten your chain depending on what cassette ratio you're running.Also, if you're running a reasonably small ratio cassette at the back you may need to change you're standard cage rear mech to a medium at least. On the opposite side of things, if you're wanting a slightly larger ratio than what you already have, your rear mech should be fine, remembering of course that you should always fit a brand new chain if you're replacing a cassette with some mileage in it. Presumably you mean a double chainset (52/39)when you say "standard"?
    Hope this goes some small way to helping....
    Let's close our eyes and see what happens
  • volvine
    volvine Posts: 409
    it is a 53 at the front i wouldnt have a clue what cassette i'm running on the back now not my strong point i'm afraid the workings :oops:
  • roger_merriman
    roger_merriman Posts: 6,165
    you will have 53/39 almost certinaly then, as to cassette if it's a new bike? or you haven't changed the cassette should beable to look up what cassette most bikes had fitted.
  • volvine
    volvine Posts: 409
    it was a brand new groupset when i bought the bike second hand full 105 groupset still had the selaphane on it all i just presumed it was a compact don't know why never bothered to check as i had been on a tripple previously but with not being able to get out as often as i would like i just feel a compact would suit me a lot better especially on the hills cause lets face it i don't really ever need the big gear so i think a 50 ring would be fine.
  • roger_merriman
    roger_merriman Posts: 6,165
    I mean what bike do you have? normally you can look up what any bike had when new. assuming not too many years ago.
  • John.T
    John.T Posts: 3,698
    Assuming you are running the latest 105 with outboard BB bearings and intend to use a Shimano compact then it is easy and should cost no more than the crankset. You will need to lower the front mech a little and perhaps shorten the chain. If the bottom run of the chain is clear of the rear mech cage when you are in small ring and small sprocket then it is OK. you would not normally use this gear anyway. You do not need to change the rear mech as a short cage one will take 50/34 with 12/27 cassette which is the largest cog that Shimano recommend for all road mechs (except 7009 Dura-ace). I am using this combo on 3 bikes and all work fine if you keep the chain as long as possible.
  • volvine
    volvine Posts: 409
    i have a Trek Madone 2004/5 the guy i bought it off made it up so it was not off the shelf
  • Mettan
    Mettan Posts: 2,103
    volvine wrote:
    is it a simple/cheap job to change over from a standard shimano 105 to a compact????? :oops: :oops:

    £55 - Shimano 4550 chainset
    £18 - External BB Cups


    Assumes Shimano - All approximate.

    If you want to spend more you could go for the 600 or 700 chainset - 4550's adeqaute enough though, if on a budget.