Cycling UK Forum

Can I use a Shimano MTB chainset with STI levers? Years ago I know this wasn't possible but have things changed?

Does anyone know if Stronglight touring chainsets work with STIs?

I want to build a low geared tourer but want to keep drop handlebars, not falts.

Most MTB chainsets should be OK, but you'll need a road front mech because the cable pull is different between road and MTB STI at the front. Or you could bodge an MTB one. You'll have to make sure that the new front mech will be OK with the range of the MTB chainset - I've never had a problem with this, but if you go to extremes there might be issues. (note: my experience of all of the above is only upto and including 9spd - no idea about the 10 & 11 speed stuff)

STI levers will only work road front mechs., but there is this I havn't tried;;;;;;http://dirtstories.blogspot.com/2009/02/salsa-fargo-holy-cow-this-thing-is-fun.html. scroll down to the F. mech. picture.

You can use bar end shifters with ATB front mechs. if you want a 22 32 44 setup. I dont know how "small" road front mechs. will cope with, but somebody who does know will be along in a minute!

Front road mechs are generally listed with a maximum big ring size and a capacity (the difference between the largest and smallest ring). I think Shimano mechs have a capacity of 20 so they shouldn't work with a 22 32 44 triple (44 - 22 = 22). Having said that, there's normally a certain amount of flexibility in the specifications so it might work.

Why not go for a "trekking" chainset? (26/36/46). Will definitely work with a road front mech and still give you a decent low gear. I have this combo on my touring bike with tiagra STI's, with a 12-34 cassette and can climb 1 in 4's with 2 full panniers (and I'm no mountain goat!).

Mister W wrote:Front road mechs are generally listed with a maximum big ring size and a capacity (the difference between the largest and smallest ring). I think Shimano mechs have a capacity of 20 so they shouldn't work with a 22 32 44 triple (44 - 22 = 22). Having said that, there's normally a certain amount of flexibility in the specifications so it might work.

There is a lot of flexibility - our tandem (9speed Ultegra STI) has 24-39-53 on the front, with no problems.

blackbike wrote:Does anyone know if Stronglight touring chainsets work with STIs?

Yes they do - perfectly.
You need a road front mech, which is likely to work with an down to 48 or 46T. For the inner ring you can go down to 24T, which, combined with an 11-34 rear cassette gives a 19" bottom gear. That's what I have, and I can get a full camping load up anything!
Best to have not more than a 10T gap between big and middle rings (although mine is OK with 12). Gap between middle and small can be whatever the BCD allows.

As has been said MTB front mechs won't work with road STI's but like Frank I've run a 46t big ring with road STI's and a road mech.
The problems start if you want to run something less than 10tooth difference ie;46 outer 38 middle as the inner cage plate on modern Shimano triple mechs fouls on the middle ring when changing up to the big ring.
With a 10t or even 12t difference everything works OK,the granny to middle change isn't a problem ,even down to 24t going upto 38t.
Stronglight Impact triple chainset works well with STI's,I have two one has 26/38/48 the other 26/36/48. CRC have them on offer at the moment,they're also square taper so none of the silly bottom bracket issues that everyone is complaining about.

Thanks for the info.

I think I'll buy a Stronglight with 46/36/26.

One thing to note is that a lot of current shimano front mechs have a minimum difference between middle and outer chainrings of 12T.
If you only have a 10T difference and set the mech height properly so the outer cage clears the big chainring by a mm or so, the inner cage plate hits the middle ring.