What cog should I not get chain rub?

Darce87

Morning all,

When I'm in the big chain ring, what cog should I stop getting chain rub on the front derailleur? I've noticed I'm still getting some rub when I'm in the 3rd cog on cassette. Should I adjust the cable tension slightly? I feel like the chain isn't crossing at this point.

Thanks

sungod

setup aside, it can vary with geometry and components, for instance on mine i can cross chain all the way without getting any chain rub

do you mean the third biggest sprocket and the chain rubbing on the lefthand side of the cage?

in that case the cage may be sitting too far out (try using the limit screw to adjust), but it could also happen if the cage isn't installed parallel or is bent

might be worth looking at the install/adjustment guide for the specofic front mech and go through it from scratch

Darce87

Yes, 3rd biggest sprocket and rubbing on the inside edge of FD

ai_1

What groupset are you using and assuming it has it, are you using the front derailleur trim?

Darce87

shimano sora

ai_1

Darce87 wrote:

shimano sora

Really going with the minimumof info here aren't you?
Current or older model? (i.e. 8 or 9 speed), Does it have trim and do you use it?

Darce87

2013 9 speed. I don't know if it has trim. IT clicks twice when shifting to small chain ring, so I guess so?

ai_1

The purpose of the trim is to move the front derailleur in slightly (without moving the chain) when using the larger sprockets to eliminate chain rub. So it sounds like your groupset comes with a ready-made solution to your problem. If you shift to a large back sprocket and are getting chain rub then engage the trim (normally a gentle click part way through a normal gear change) to engage the trim and move move the derailleur away from the chain.

Darce87

I'll give it a go!