12-30 cassette short cage mech, will it work?

ravey1981
ravey1981 Posts: 1,111
edited May 2015 in Workshop
I normally ride with a 11-25 cassette and 34-50 compact chainset. I have some hilly sportives coming up and I'd like to get a 30t cog on the back if possible. Will a short cage mech take it? (Ultegra SL 6650)

If not I'll have to make do with a 28, I know a longer chain will be needed in both cases....

Comments

  • dnwhite88
    dnwhite88 Posts: 285
    Several people on here have tried it with success even through shimano say you can't, you may have to adjust the b screw on your rear mech though and chain length
    "It never gets easier, you just go faster"
  • ravey1981
    ravey1981 Posts: 1,111
    Cheers, yeah I've just done a bit of googling and there seem to be conflicting stories. I think I will buy the cassette and try it. I can always swap a mtb rear mech in that I have spare for one off rides...It will look horrendous though!
  • arlowood
    arlowood Posts: 2,561
    ravey1981 wrote:
    Cheers, yeah I've just done a bit of googling and there seem to be conflicting stories. I think I will buy the cassette and try it. I can always swap a mtb rear mech in that I have spare for one off rides...It will look horrendous though!


    A quick search on here would confirm that many have done the combo of 12-30 + short cage rear mech without issue - including myself with both Ultegra and 105 rear mechs. Mostly it was a straight installation with no tweaking but on one occasion I had to fiddle a bit with the B-screw to get smooth operation.

    Just go for it - I don't think you will have any issues
  • dj58
    dj58 Posts: 2,217
    You can also use a longer B tension screw if you can't obtain the required clearance with the existing one,
    as in this thread. viewtopic.php?f=40004&t=12952412
  • Monty Dog
    Monty Dog Posts: 20,614
    No definitive answer as it often depends on the geometry of your rear mech hanger and whether the top jockey wheel fouls the biggest sprocket - the only way to know is to try it.
    Make mine an Italian, with Campagnolo on the side..
  • antonyfromoz
    antonyfromoz Posts: 482
    I am currently running a short cage sora 9speed with an 11-32 cassette and I have had no issues. I didn't have to adjust the b screw but I did change the chain at the same time I installed the cassette as I also put a single chainring on the front. This is something you might need to consider too, or you might have to be very careful not to cross chain if it's a bit short.
  • drlodge
    drlodge Posts: 4,826
    You can probably get a short cage rear mech to work with a 30 tooth sprocket althought the change might not be uber smooth. The bigger issue is one of chain take-up capacity with 34-50 and 11-30 that's alot of chain. 12-30 would be a better bet and run the chain as long as possible (with some tention in the RD when in small-small) but you may end up not being able to change into big-big without ripping the rear derailleur and chain apart in which case be very careful not to run big-big!
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
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