Troublesome front mech

ricktabor1

Just wondering if anyone had any advise.

I've put front mechs on bikes plenty of times and had no problems but this seems to have me beat.

I'm putting a Tiagra triple on a Trek Pilot 1.2 2006. The chainset is a Bontrager Select triple. I can't seem to get the full swing. I do the usual stuff and put the inside left as close to the chain as possible (without rubbing) on the small chainring (large sprocket at rear). When i shift to the big chainring and set the gears to the highest gear, the chain rubs on the inside right of the mech.

I've tightened the cable to hold the mech out but this tight cable means that the mech then won't shift the chain on to the middle ring. I've tried putting the mech higher up the seat tube, i've also tried pointing the mech more towards the frame. Every result is the same.

Has anyone got any tips on positioning of the front mech? The standard of having the mech in line with the chainrings and 2mm above the large ring doesn't give the full swing.

Hope i've not over explained this!

Thanks.

topdude

Is it possible that the chainrings are spaced differently on the two chainsets?

Have you fitted a MTB front mech which will not be compatible with STI shifters ?