It appears that there are similar threads, so I'll reformulate it with more specific questions and taking the cue from comments.

I am assembling my brand-new touring bike on a LHT frame, and I'd like to make STI shifters work on it. My setup at the moment is

  • shifters shimano 105 STI
  • crankset shimano LX 48-36-26
  • cassette+chain 10 speeds shimano XT

Apparently to make STI work with rear MTB derailleurs, one needs to take the 9 speed RD, since new 10 speeds have different pull ratio. What concerns me most, at the moment, is the dirtiness that comes from the choice:

  • using a 10s chain on a 9s rear derailleur, due to different thickness
  • using a road FD (e.g. shimano 105 triple) with a MTB RD and with a 48-36-26 crank
  • other issues that you will suggest

do you think it would affect shifting smoothness and durability of the setup to use this kind of melting-pot solution?

bonus question: on this compatibility reference, are you aware of any difference between shimano SHADOW XT RD and normal XT RD?

bonus solution: I am not a STI religious, so if issues are real I might shift to barends to make a fast and long lasting fix. Anyway, I'd like to stay on brifters if problems are not that significant.

thanks a lot!

  • 1
    The difference between brifters and bar-end shifters is pretty significant, I wouldn't make the change just because of a minor hassle getting the right components. Better to buy an RD that works IMO – Móż Jul 17 '16 at 23:27
  • sure, I actually have no experience with any of the two (always toured with a MTB) so that would be a major change in any case. Let's say there is also barends-vs-sti pros and cons hidden question :) – LorenzoP Jul 17 '16 at 23:35
  • 4
    Possible duplicate of Shimano Compatibility and many others. – mattnz Jul 18 '16 at 2:12
  • Sorry, have you not worked out that the speed parts are designed for is pretty important, even from the same manufacturer? It's just that you've managed to work out that you need 9-speed components, yet you're still proposing to buy a 10-speed front derailleur. I'd be tempted to take the bike to a shop and ask them to help. – PeteH Jul 18 '16 at 6:56
  • sorry peteH, but I don't understand your comment (and its tone). Everything in the setup is 10 speed, I am using 9 speed RD just because the pull ratio seems to be correct in that case, i.e. in practice I am still using 10 speeds. I don't see how taking a 9 speed FD would help. Also, if I were into taking the bike to a shop I wouldn't write on this website, would I? I thought that the policy of the website were to exchange advices, not to send people to the closest bike shop for them. – LorenzoP Jul 18 '16 at 7:23

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