DOS

Working with 4 bikes each with ultegra front derailleurs but only on the bikes with ultegra cranksets can I easily eliminate chain rub in all gears.

Bike 1: Custom titanium Road bike with 6800 FD and ultegra cranks, chain passes the cage in all directions after minor adjustments of limit screws and cable tension using in line barrel adjuster

Bike 2: Salsa gravel bike with R8000 and ultegra cranks, rub eliminated following set up directions, adjusting combinations of L, H, and cable tensions screws on the derailleur

Bike 3: CAAD10 road bike with R8000 FD and SRAM Red cranks. Chain rub in big/big combo eliminated, but after much tinkering and smaller cap between chain and cage when in highest gear so much less room for error

Bike 4: Salsa Gravel bike with r8000 and praxis cranks.Could not eliminate chain rub in big big combo without creating rub in highest gear.

shelbyfv

I think you are doing OK. Shimano doesn't expect us to be able to consistently use big/big w/o rubbing.

mpetry912 

Right. The "Big/Big" and "Small / Small" combinations are the extremes of chain tension and slack, as well as chain angle. This is particularly true of bikes with short chainstays.

Other gear combinations can approximate the ratios in those combinations. So, don't use them.

For best shifting the outer piece of the front derailleur cage should be parallel (in plane with) with the large chainring.

Mark Petry
Bainbridge Island, WA USA

alcjphil

Do your 2 Salsa gravel bikes have the same length chainstays? If one is shorter than the other that might furnish a clue