Cassette alignment

[Dan77]

I'm using one road bike for both indoor training and outdoors.

I fitted an identical cassette to the turbo trainer. It's an 11-34 Ultegra so it has a spacer.

I've had to reindex the gears though when swapping from trainer to wheel and vice versa. Do I have to just get used to it and try to figure out how many times to click the gears to get the alignment right each time (Di2 so actually relatively easy to adjust)?

I'm wondering if trying it without the spacer on the trainer might solve it.

Any suggestions?

 

[Sharky]

Worth trying.
You could also try moving a spacer from one end to the other to move the cassette over in the direction needed. Would disable the sprocket where the spacer has been taken from or to, but might make the rest work OK.

 

[twentysix by twentyfive]

Measure up. Have you got some of these

. Then you'll be able to diagnose what's what.

 

[Dan77]

Measure up. Have you got some of these View attachment 554697 . Then you'll be able to diagnose what's what.

I have those at work yes. Inside of frame to inside of smallest gear?

 

[si_c]

I have the same problem with my trainer - it requires a slight adjustment of the rear derailleur to get the gears indexed on the wheels compared to the turbo. I'm running mechanical though so I know that on the Racelight it's three clicks inwards of cable tension moving from wheels to trainer. Maybe this is an argument for a dedicated turbo trainer bike

 

[twentysix by twentyfive]

I have those at work yes. Inside of frame to inside of smallest gear?

Yep - that sort of thing