Have a 38-50 chainset set up on my road bike which I find a bit heavy going. It’s a square taper TA Specialities bb with an FRM chain set (all old kit). I’ve a Middleburn triple chainset spare so wanted to try 34-44 or similar. Problem is the front mech won’t shift outwards far enough to push the chain onto the outer ring with a 107mm bb. A 103mm bb might help, or a triple mech???

Or is mixing mtb and road bike always prone to failure?!

Thanks

You can mix road and MTB, and even campag and shimano, but only certain combinations work. CTC Forum might be your friend here, many tourists favour square taper BB / MTB gearing

Have you looked to see if you can get rings for your current setup?

Try SJS cycles or spa cycles.

Thanks – my current crankset is 130BCD so unable to go lower than 38T I think.

What sort of shifters are you using? That’s usually the limiting factor when it comes to adding an extra chainring…

He’s not adding a 3rd chainring.

Is 2mm difference going to be enough? that’ what the 107 -> 103 will get you. IIRC mtbs have different chainlines in which case this might just not work.

The bike has Veloce shifters, but wanting to stick to 2 rings. And yep, 2mm doesn’t seem much, it’s nearly shifting so hoped it might make the difference! Wonder if a triple front mech could do the job, as chain line with the Middleburn cranks looks ok