Anything special needed to set Ultegra 6800 FD trim?

[jojoma]

Hello,

I like riding in the 53/23 or 53/25, but the chain rub is pretty bad. In general, the front shifting on the new Ultegra (and DA) is outstanding, but there is still rubbing even when I do the soft click trim. Any thoughts on how to make it better? Having no barrel adjusters complicates things more.

 

[jpr95]

That's called cross-chaining, and it's pointless to try to make adjustments to get it to do something it wasn't designed to do. You're just wearing out your chain much more quickly. 40/17 is about the same as 53/23 and 40/19 is about the same as 53/25. Both will give you a much straighter chain line, which will greatly reduce wear.

 

[oldbobcat]

I've been setting up 6800 on new Treks for several months, and I've been having no trouble eliminating rub when cross chaining, especially with big-big.

With your chain in the highest gear (big-small), look closely at your front derailleur. First, make sure the outer plate is absolutely parallel with the big ring. Next, look at the clearance between the chain and the outer plate. It should be 0.5-1.0 mm, according to Shimano. Lacking a feeler gauge to get in there, if you drop into trim with the chain in this position, you should get a consistent rub. If you don't, let out a little cable and adjust the outer limit screw so the derailleur hits the screw and maximum cable tension simultaneously. Of course, this is a lot easier with an inline adjuster.

Small-small is my sacrificial combo, mainly because with compact cranks the rub of the chain isn't on the derailleur, it's on the inside of the big ring. But while I don't dwell in big-big, I use it for short bursts, like kicking over the top of a rise that got a little harder but not hard enough to drop to the small ring. The cross-chaining police haven't arrested me yet.

 

[jojoma]

Thanks bobcat, I'll play with it as you suggest. I am also willing to sacrifice small-small, as well as big-small. I'm not in the 53/11 often.
But big-big can be nice to power through a moderate rise without having to drop into the small ring and further disrupt any rhythm.