Looks like Ultegra are both bearing not bushing and a tenner to replace so I think I'll just get some of those. No idea on mileage. "Lots" would be a reasonable guess.
"Precision sealed bearings in both guide and tension pulleys keep drivetrain smooth and friction-free."
Yeah, they are bearings. Hope do some replacements with nice bearings that I've stuck on some worn out 105 derailleurs in the past. I'd imagine they are comparable to ultegra, though.
Looks like Ultegra are both bearing not bushing and a tenner to replace so I think I'll just get some of those. No idea on mileage. "Lots" would be a reasonable guess.
"Precision sealed bearings in both guide and tension pulleys keep drivetrain smooth and friction-free."