that bike nut
Join Date: Jul 2007
Location: Chicago north
Bikes: 2010 Motobecane Immortal Force 90' Trek 1400; 90' Trek 850; 06' Trek 520; 01 Iron Horse Victory
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elimating front dreailer rub
Hi all, my front derailleur is driving me crazy.
It used to be so that there were two positions, 1 for each chainring, and I could run through all gears on the rear without rub, even the cross ones.
Now I am unable to get it in far enough so that on lowest gear 42/23 it doesn't lightly rubs the inner cage face. It have the L limit screw all the way loose and the cable fairly slack as well as installing a washer in between the plates at the bottom where they screw together. Yet on 42 13-15 I have to adjust the dérailleur out so the chain doesn't rub the outer face.
Stuff I checked tried
Checked chainline measures a perfect 43.5mm.
Checked dish on rear wheel. Also perfect.
Checked for CR wobble and bent spider tabs so that it is pretty much imperceptible.
I noticed when the dérailleur is set as far inward as possible the cable rests on the plastic cover over the front dérailleurs lower pivot. The cable curves arround it and goes to the anchor guide/nut.
The angle/height adjustment seems perfect and I've never touched it. It also shifts fine. Any suggestions would be appreciated.
Bike 1990 Trek 1400
Crankset shimano fc 1055
bottom bracket UN54 68X113 British threaded
7 speed 13-23 cassette
Chain KMC Z50 new but did it on my old Sach's chain as well