front derailleur adjustment, shimano acera



gt3413

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Apr 28, 2006
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My chain is rubbing on my front derailleur while its in the center ring on the front and the next to largest ring on the rear. I don't remember which screw to turn on the front derailleur to make this tiny adjustment. Its rubbing on the side of the derailleur closest to the "small ring". Please help. Thanks, Greg
 
gt3413 said:
My chain is rubbing on my front derailleur while its in the center ring on the front and the next to largest ring on the rear. I don't remember which screw to turn on the front derailleur to make this tiny adjustment. Its rubbing on the side of the derailleur closest to the "small ring". Please help. Thanks, Greg
Uhh, neither. The screws on the front derailleur are stops that limit the motion so that you don't throw the chain off either the big ring or the granny. They don't have anything to do with alignment within that range. Somewhere, like coming out of your shifters you should have a barrel adjuster, give it twist to adjust cable tension which will adjust the mid throw alignment. The barrel adjuster could be in several places depending on the bike and shifters you use, but take a look there should be an adjuster somewhere along the front cable housing.
 
I follow the link, click on acera front derailleur and all it lists are the 2 different types. There is no "more" button that actually takes me into the document. HELP. Thanks, Greg
 
if you haven't cured it yet: to me it sounds like the front cable is too "tight"..pulling the derailleur guy too far towards the big ring. IMHO you need to make it "looser" by either screwing in the little barrel adjust at the shifter as suggested OR by releasing the cable clamp at the derailleur body and letting a little bit more cable slip past, then reclamplng.

The derailleur is spring loaded to jump down to your small ring ( I think), and more slack will let it move in that direction, and hopefully out of contact with the chain. Generally: center up the cable barrel adjustment nut at the shifter, then adjust the cable at the derailleur, then fine tune at the shifter.

Having the rig up on a work stand helps inordinately... you can actually see what is happening, and test different adjustments in the privacy of your home. If you plan on working on bikes at all in your life, one might be a great investment.

Cheers!

j fairbanks





gt3413 said:
I follow the link, click on acera front derailleur and all it lists are the 2 different types. There is no "more" button that actually takes me into the document. HELP. Thanks, Greg