Front derailleur adjustment

thechanger

After watching several YouTube videos and lots of wasted time fiddling about, I'm convinced it's impossible for the chain not to touch it either in smallest or biggest gear.

I recently installed a new Shimano Ultegra 6700 Double 10sp Front Mech on a compact. And every time I adjust it for the big ring, it tends to touch the chain if I drop down to a big gear. If I readjust it, then it will touch when in granny gear.

Could anyone offer some advice, please.

Thanks

DirkVoodoo

thechanger wrote: »

After watching several YouTube videos and lots of wasted time fiddling about, I'm convinced it's impossible for the chain not to touch it either in smallest or biggest gear.

I recently installed a new Shimano Ultegra 6700 Double 10sp Front Mech on a compact. And every time I adjust it for the big ring, it tends to touch the chain if I drop down to a big gear. If I readjust it, then it will touch when in granny gear.

Could anyone offer some advice, please.

Thanks

You mean you are cross chaining?

Plastik

Advice: You're not meant to be in the big ring/biggest cog on the cassette or small ring/smallest cog.

Mycroft H

If its adjusted properly it will it will still rub in large sprockets in the big ring as its not exactly designed to run in the big ring with the large sprockets as the chain will be operating at an angle if that makes any sense. Your aim is to try to keep the chain parallel with the frame of the bike and not operating at an angle.

In doing this your going to have to restrict the usage of the bigger sprockets on the rear when using the big ring to the smaller half of the cassette to prevent chain rub. When you need the easier gears drop into the small ring and use the larger cogs in the rear. This way you will always have a decent chain line. A nice chainline prevents premature wear of the chain.

DirkVoodoo

The "red" gears are the cross chaining gears, as you can see, you still get the similar gear ratios without having to do it. It's a bad habit, although sometimes the constant shifting at the front on a compact can be a PITA, but you really shouldn't do it.

thechanger

Plastik wrote: »

Advice: You're not meant to be in the big ring/biggest cog on the cassette or small ring/smallest cog.

Why do you think I'm doing that – not cross chaining.

Let me explain again. I've set up the derailleur. Firstly I put the chain big cog rear / small front ring, the chain doesn't touch the derailleur. When I go to big ring / small cog back, it touches. I readjust the derailleur so now the chain doesn't touch when I'm big ring/small cog, but does touch big cog rear / small front ring. Do you follow?

It's like you gotta adjust the derailleur if you plan to climb or time trial.

Any tips please?

Hatcho

Sounds to me like you need to adjust the limit screws so that the derailleur can travels the correct amount to prevent chain rub in the conditions you describe.

Depending on which side of the front cage is rubbing the chain in each case, the travel may need to be restricted or expanded by adjusting the limit screws.

funkyjebus

Your shifter probably has trim, which will stop the chain rubbing. Sounds like your limit screw to me though

ashleey

Adjust upper limit screw with chain in big front small rear first then adjust lower limit screw with chain on small front big rear. Before this, ensure that derailleur is parallel and at height just above chain when in big front ring. Clearance in all these cases should be about 1mm. Then adjust indexing so chain drops nicely into place when shifting. Any rubbing can be adjusted as shimano shifters allow trimming to move the derailleur further out if needed using the shifter. If you get the order of adjustment wrong it won't set up properly. Park tools website is the best. Good luck