Ultegra RD and larger cassette

Boddo
Boddo Posts: 6
edited November 2012 in Workshop
I have a Cube Peleton Race with an Ultegra RD 6700 ss and want to look into the largest rear cassette I can run with it (as I am intending to do the Etape next year and think I will need every tooth available...!!). I'm no mechanical whizz so I will be using my local bike shop to assist but wondered what I could expect go up to without major reconfiguration / cost? I think Shimano say 28T as the largest recommended but I have seen reference to 30 or even 32 elsewhere though its all a bit vague. Has anyone got any recommendations / experience they could share?

Comments

  • Ride hard
    Ride hard Posts: 389
    You can realistically go up to any size you want, however, you will start having to mess with RD and chain lengh if you go up too high.

    I've got the Peloton SL which has an almost identical set up as you (ie short cage RD and 12-28T cassette), so running a 30T might be alright (but don't quote me on this), but with a 32T you will definetely need to lengthen your chain as the big front ring/big cassette cog will be too extreme. You might even have to go up to a medium cage RD as it might not allow enough clearnce between the top jockey wheel and the cassette.

    Use the search facility on here as this topic is discussed on a regular basis.
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  • Boddo
    Boddo Posts: 6
    Thanks Ride Hard, much appreciated
  • 28T is the specified max for an Ultegra RD 6700 (ss or gs). Fart around with with the B adjustment screw and you can bodge it to accommodate a 30T. With a 32T top jockey wheel will almost certainly be far too close to the large sprocket. You really want to be looking at fitting a mountain bike mech to go much beyond 28T.
  • Monty Dog
    Monty Dog Posts: 20,614
    Most Shimano road mechs struggle with over 28t sprockets - it's due to the distance of the upper jockey wheel from the wheel centre - MTB mechs have a bigger offset and hence can take a bigger sprocket. It's nothing to do with chain length.
    Make mine an Italian, with Campagnolo on the side..
  • rrsodl
    rrsodl Posts: 486
    Monty Dog wrote:
    Most Shimano road mechs struggle with over 28t sprockets - it's due to the distance of the upper jockey wheel from the wheel centre - MTB mechs have a bigger offset and hence can take a bigger sprocket. It's nothing to do with chain length.

    105 5700 GS can take up to 32t sprockets
  • GS has more capacity to allow a front triple, it only has the same max rear sprocket rating as a SS.
  • rrsodl
    rrsodl Posts: 486
    GS has more capacity to allow a front triple, it only has the same max rear sprocket rating as a SS.


    Shimano 105 5701 10sp Rear Derailleur
    Short Cage Features:

    10-speed 105 wide link rear derailleur short cage - SS
    Maximum low sprocket 30T
    Maximum front difference 16T, total capacity 34T
    Average weight 221 grams

    Medium Cage Features:

    10-speed 105 wide link rear derailleur medium cage - GS
    Maximum low sprocket 32T with double chainset
    Maximum front difference 22T, total capacity 40T
    Average weight 232 grams
  • We were talking about the 5700
  • andy_wrx
    andy_wrx Posts: 3,396
    The OP has a 6700 SS and that's what he's asking about !