R770 shifter and shimano 4700 / 5700

mcstumpy
mcstumpy Posts: 298
edited August 2017 in Workshop
Hi,

Apologies if dumb question but want to be sure.....

I currently have r770 ultegra 10 speed trigger shifter with Tiagra 4600 RD (short cage).

I'm going to use this bike for a bit of off road and with some steep bits involved would like to switch to a cassette with 32t biggest cog, so looking at 4700 and 5700 gs RD''s (or would either of these cope with 34t?)

Is there any reason my R770 won't be compatible with either of those? It hadn't even crossed my mind until I read the wiggle reviews for the 4700 RD, so just want to be on safe side. Thanks.

Comments

  • timothyw
    timothyw Posts: 2,482
    You want the 5700 gs (or 4600 gs or any 9 speed long cage rear derailleur (MTB or Road) but that's a whole other story).

    New Tiagra derailleurs are only compatible with new tiagra shifters (or 11 speed, but you lose a click....)
  • mcstumpy
    mcstumpy Posts: 298
    Great, thanks for that.

    By whole other story.... are we starting to talk complicated bodge?
  • lesfirth
    lesfirth Posts: 1,382
    If you want to go to 32T sprocket you need a 5701 rear mech. Shimano say the limit on a 5700 is 30T. I agree with them I could not get one to work with a 32T sprocket.
  • timothyw
    timothyw Posts: 2,482
    McStumpy wrote:
    Great, thanks for that.

    By whole other story.... are we starting to talk complicated bodge?
    No, it should* be that you can use any Shimano 9 speed derailleur with the required capacity for the cassette you want, this is how lots of touring bike riders use wide range cassettes with drop bar brifter set ups.

    If you are using a mountain bike derailleur you may wish to check you're getting one with a barrel adjuster, as they often don't have them (as they have an adjuster at the shifter end, although it might be you have that on your tiagra flat bar shifter anyway?)

    I just didn't want to overload you with extraneous information given you'd put forward a straight choice...


    * I've not heard contrary, but you might want to confirm this information elsewhere... Shimano like to change things, as you've found with new tiagra. I know the new Sora r3000 group uses the same pull ratios as ever at the rear.
  • mcstumpy
    mcstumpy Posts: 298
    Thanks, Timothy, much appreciated

Categories