Front Mech Fettling
A step-by-step guide to front mech fettling...
by Dirt HQ
On the face of it, the front derailleur is a paragon of crudity. It's just a couple of bits of metal pushing the chain off one chainring and hopefully on to another. But the positive spin on crudity is simplicity. Unfortunately, setting the front mech up isn't always all that simple, and with narrower chains and more gears it's now fiddlier than ever. Here's how to go about it...
There’s a good chance that a test ride will show up all sorts of deficiencies. Consult our handy table for the solutions:
|Mech won’t shift from big to middle||Turn barrel adjuster clockwise|
|Mech won’t shift from middle to small||Check low limit screw. If that’s OK, turn barrel adjuster clockwise|
|Mech won’t shift from small to middle||Turn barrel adjuster anticlockwise|
|Mech rubs on small chainring||Wind low limit out slightly|
|Chain falls off when shifting to small ring||Wind low limit in slightly|
|Chain falls off when shifting to big ring||Wind high limit in slightly|
|Chain won’t go into big ring||Wind barrel adjuster and/or high limit screw|
|Chain rubs in big ring||Turn high limit out slightly. If no joy, check cage alignment|
|General erratic shifting performance||Clean, lube or replace cable. Check mech for wear – if there’s a lot of slop in it, replace.|