"I've been having no end of trouble setting up my eTap with a Rotor chainset. I don't think it's ever going to work. I've had to put a 3 mm spacer on the BB to move the crank out far enough that it doesn't foul the front mech, but I'm still getting excessive chain rub. This is with a BSA 68 mm wide BB shell though, so I think that's probably the main issue."
Fortunately I didn't have to find this out the expensive way.
Quoted from @andyp:
"I've been having no end of trouble setting up my eTap with a Rotor chainset. I don't think it's ever going to work. I've had to put a 3 mm spacer on the BB to move the crank out far enough that it doesn't foul the front mech, but I'm still getting excessive chain rub. This is with a BSA 68 mm wide BB shell though, so I think that's probably the main issue."
Fortunately I didn't have to find this out the expensive way.