My daughter presented me with a problem that I need some advice on. She
rides a Trek 1220 (several years old) that has always had problems with
shifting. More than one shop has tried to solve it with poor results. This
bike uses Shimano RSX indexed shifters/brake levers, a 46-36-26 chainwheel
setup, 14-30 7-speed rear cluster. The seat tube diameter is 34.9mm (1
3/8"😉. It's currently fitted with an Ultegra front derailleur, made for a
braze-on mount, and it's mounted via a clamp that fits the seat tube
diameter. The Ultegra derailleur is obviously the wrong choice here because
it's optimized for much larger chainrings and has to be positioned too far
up the seat tube to prevent excessive chain rub. That results in unshipping
the chain 90% of the time when shifting from the middle to outer chain ring.
So, what I need is a front derailleur for either braze-on mounting or that
fits a 34.9mm tube, and is optimized for the smaller chainring setup.
Anyone know of such a derailleur? (bottom pull).
Floyd Sense
Angier, NC