I’ve recently come across a mis-match with building up the Mrs’ new flat bar tourer and am looking for advice, please.
The setup is 3×10, with a new touring XT Shimano triple chainset, so 48,36,26. I’ve fitted new Tiagra 4703 shifters and a 11-32 block. The mech is a new Shimano 105 (5701) and it’s clear that the leverage ratio is incompatible as it works down towards the smaller sprockets, eventually jumping two gears from either 7-9 or from 8-10.
I think that what I need is an 11 speed rear mech, which will move the correct amount across the whole block with each click of the 10 speed shifter.
Any thoughts on that, and can it be either a MTB or road 11speed mech or must it be a road mech?
Is the new 11spd XT Touring (RD-T780), long cage mech compatible with the 4703 shifter?

RD4700GS will definitely work

I’m pretty sure the GS versions of 5800 and 6800 will also work. I don’t know whether the MTB ones will.

Sorry, don’t understand the need for an 11 speed mech when all the bits are 10 speed. I’d be more inclined to check for a bent hanger.

Sorry, don’t understand the need for an 11 speed mech when all the bits are 10 speed. I’d be more inclined to check for a bent hanger.

Because Shimano changed the geometry of the 4700 rear mech to align it with their 11spd rear mechs (even though it is still 10 speed)

Fifeandy- the leverage ratio on Shimano 10 speed kit has recently changed, so that older 10speed is no longer compatible with the latest 10 speed; I’m lead to believe that the leverage ratio of a new 11speed rear mech is the same as the latest 10 speed flat bar shifters, which is what I’m trying to check..
The frame is brand new and is straight.

Thanks Simon.

simondbarnes – Member
Sorry, don’t understand the need for an 11 speed mech when all the bits are 10 speed. I’d be more inclined to check for a bent hanger.
Because Shimano changed the geometry of the 4700 rear mech to align it with their 11spd rear mechs (even though it is still 10 speed)

This. IIRC the only ones listed as compatible are the 4700 series ones.

So you either need a 4700 compatible rear mech, or 5700 flat bar shifters (if such a thing exists.)

Do people still check the shimano compatibility charts. Or the CTC compatibility stuff (if it’s still kept up to date!)

Shimano compatibility charts were what I used most recently (note that front mechs are new geometry too – on doubles this does give very nice shifting, but total incompatibility with previous STIs.)