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Rear Derailleur upgrade for Specialized Secteur

skippy_77skippy_77 Posts: 35
edited January 2019 in Workshop
I want to upgrade my Shimano 2300 rear deraileur. I've got a triple crankset and I'm not sure what to upgrade it with.

I was looking at the 105 5700 derailleur, or similaro derailleurs. Some show 10 speed and some are 7-8.

Can a 10 speed derailleur work on an 8 speed cassette?

I'm not sure if I require a long or medium cage.

I've been looking at these; ... -prod38673 ... prod150050 ... prod137774 ... -prod85966 ... prod173487 ... prod137898

Triple Chain ring, 52 x 39 x 30T
Rear Cassete ; Shimano HG-50, 8-speed, 12-25t



  • imposter2.0imposter2.0 Posts: 12,015
    Obvious question - is your current mech broken? If not, what are you expecting a replacement/upgrade to achieve?
  • I've had the bike 8 years+ it's got next to new chain and rear cassette.

    I don't ride this often as I prefer to go in the forest on my FS MTB however I want to ride some 100 km rides this year.

    I've always found the rear shifting stiff and cluncky so I just want to do a cheap upgrade that will give me a slightly better ride, faster and smoother cahnges.

    This isn't a proper racing bike as it has a large crown it's more for comfort and ride.

    I like this riding style as it's similar to the way I ride my MTB.

    The upgrade is purley just something better than what derailleur is already on there, if for a few extra £ I can get a better one than fair enough, anything must be better than what's already on there.
  • keef66keef66 Posts: 13,123
    Just replacing the rear mech is unlikely to transform your shifting from stiff and clunky to fast and smooth. Cables and shifter will be having an influence too.

    My old 9 speed Tiagra shifts if anything a bit better than the 5700 on the other bike...
  • You'll need an 8-speed rear mech to work with your current groupset. Not sure which are 8-speed any more, you'll have to Google that one. Live it's been said above, I doubt a new rear mech will make much difference at all.

    You could throw on a new 10-speed groupset That'd be an upgrade.
  • Any eight or nine speed mtb or 8-10 speed road (except 4700) will do.

    To decide what length you need, add the difference in teeth between the rear and large and small, and front large and small cogs. This will give you your capacity. Check this against the published figure.

    Finally, as they've said, cables and outers will probably improve it enormously. And check the hanger for alignment.
  • Hi Mike,

    I upgraded the rear mech on my 2011 Secteur to the Shimano Sora R3000 (your second link) and it works fine. You'll need a long cage if you want to keep a triple set-up.

    If you want smoother shifting all round, then consider a whole groupset upgrade and changing to a compact 50/34 chainset up front and an 11-32 cassette on the rear.

    Hope that helps,
  • Thanks Asif,

    However the Sora R3000 doesn't come as a Long Cage, only Medium and Short.

    The Acera M3000 Shadow comes as a long cage

    Would this be a better option?
  • Yes, go with the Acera. I followed the link and in the Q&A section, someone asked if it's suitable for a triple crankset and the answer was 'yes'.
  • To be fussy, could i get away with running the 105 5701 with teh triple as a medium cage?

    I've already got 105 brakes one and just want to keep the theme, yes I know it's just a badge, but in theory would it still work on an 8 gear triple setup?
  • keef66keef66 Posts: 13,123
    Shimano road rear mechs come in short and medium. Medium is needed for a triple (I have a 105 5603 equipped bike) so yes, your 5701 rear mech should be fine as long as the 8 speed chain fits between the side plates...
  • Bear in mind that the 5701 will only technically work on a road triple if the rear cassette goes no larger than 28.
  • keef66keef66 Posts: 13,123
    Bear in mind that the 5701 will only technically work on a road triple if the rear cassette goes no larger than 28.

    So he should be fine as he originally posted:

    Triple Chain ring, 52 x 39 x 30T
    Rear Cassete ; Shimano HG-50, 8-speed, 12-25t
  • Thanks, I'll go for the 105 5701

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