Mixing road and MTB gears?

rustychaincp

I'm building a flat bar road bike. Can I use XT shifters with say a 105 mech? And are there any differences in the blocks, or just the gearing and range?

Thanks

Rusty

willbevan

i'm running a MTB block with MTB mech and road shifters, initally was a MTB block, road mech, and road shifters

As for the blocks its just range I think, and the mechs have the same actuation ration (right word) so dont think its a problem

i would presume that as long as its the same speed it will work okay (shifters and block now, not the mech), but someone please chime in here that has used MTB shifters with road kit?

maddog 2

rear is fully compatible - mtb shifters will work a road mech.

A road mech will work with a max sprocket size of 27t (officially) and one or two more in practice, if you use the tension screw on the mech.

front is not so simple - if you run a double c/set you can get away with running a road f. mech. The shifters will pull more cable that the road f. mech requires but you can easily get round it by using the limit screws.

However, if you want to run a triple then you'll need a dedicated flat bar shifter.

rustychaincp

Thanks for the responses.

I'm looking at a triple for the front. If I've understood correctly, I can use a MTB shifter with a MTB front mech, or a road shifter with a road front mech.

Are there any compatibility issues with using a MTB front mech and a road chain set (eg due to the greater range/size of chain rings)?

yogi

I've been using 105 Sti levers with an LX MTB front mech,LX rear mech and a CODA double-ring MTB chainset on my cyclo-cross bike with no problems. I can use a mountain bike rear cassette or a road one, thats the beauty of Shimano compatibility.

Are there any compatibility issues with using a MTB front mech and a road chain set (eg due to the greater range/size of chain rings)?

Yes - the max size that an MTB front mech goes up to is usually 48 teeth. Some only go to 46 - you would need to check.

geoff_ss

I'm using LX shifters with a 105 rear mech and it works perfectly. I don't have a problem with the front as I'm using a Truvative 44/32/22 chainset anyway. I'm using a 13/25 9 speed cassette. I don't think there are any 10 speed flat bar shifters so you're limited to 9 block at the rear.

I can pedal the 91" top gear at 40 kph easily - after that I save my energy for the next climb and freewheel. I think my top gear was lower than that when I was doing audaxes (84") and I still managed a sub 20 hour 400km quite comfortably. If you feel the need for a higher gear then a 48x11 is 117" which is pretty high by most standards.

It's funny, but when I used a 6 speed block with double chainset (what would now be called a compact, I think) I always knew exactly what gear I was in and what it was in inches but now with a triple and a 9 speed cassette I haven't a clue. Not that it matters, I guess

Geoff

maddog 2

mtb front mechs don't shift well on road triple c/sets, and I would discourage you to try, as it'll cause no end of problems IME.

you can get 10 spd flat bar shifters (SL-R770, see Shimano website)

If you want to run a triple rustychain then you'll need either

1. a flat-bar front shifter (eg SL-R440) and road f.mech, or

2. Use a mtb front shifter, f. mech and c/set