changing rear casette

noodlehat
noodlehat Posts: 10
edited March 2017 in Road buying advice
Hi All,

Quick question regarding changing my rear cassette. I know how to do so just want to check that kit i'm changing is compatible or if i have to upgrade derailleur for extra teeth?

Bike is scott speedster S55 2012, has Shimano 2300 series and SORA components which is fine for me. Rear cassette is 8 speed 11-28T, looking to upgrade to CS-HG50 8 speed 11-32T as i live on Dartmoor and my commute home has a 18% incline near the end which is defeating me. Believe front is 50-34T.

Question is can the SORA rear derailleur and existing chain take these extra teeth? Or do i need to upgrade these as well?

Any advice would be great.

Comments

  • arlowood
    arlowood Posts: 2,561
    If you have the standard Sora 8 speed rear derailleur as in the link below

    http://bike.shimano.com/content/sac-bik ... -2300.html

    it looks like your 28 tooth max is actually pushing the spec according to the Shimano docs. If that's the case then you are unlikely to get away with a 32 tooth max.

    I think from recollection that you could get away with a MTB rear derailleur as I seem to remember that the pull ratios are the same for 8 and 9 speed across the road/MTB range
  • noodlehat
    noodlehat Posts: 10
    ahh thanks, thats the one by the looks. Hmm so looks like ill have to replace that and assume longer chain?
  • Alex99
    Alex99 Posts: 1,407
    noodlehat wrote:
    ahh thanks, thats the one by the looks. Hmm so looks like ill have to replace that and assume longer chain?

    Try it first. You might find that it's OK. I ran an 11-34 9 speed with a medium cage road derailleur on holiday and it was fine. Otherwise, yes, a 9s mountain bike rear der will be fine.
  • keef66
    keef66 Posts: 13,123
    And you don't have to say rear cassette. Everyone knows it goes at the back. The things at the front are chainrings.

    Yep, MTB rear mech if you want to use climbing friendly cassettes.
  • noodlehat
    noodlehat Posts: 10
    thanks all, have put it on, seems fine a bit overstretched when on max rings but should be okay
  • Bobbinogs
    Bobbinogs Posts: 4,841
    Sounds like you need either a new chain or an extra link or 2. 8 speed pins can be reused, iirc, or you could reuse an inner link and quiclink option to err on the side of caution.

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