Ultegra DI2 Chain length

[la85]

Hey all,

I have a new Canyon Inflite which has Ultegra DI2 and GRX rear. I want to replace the 46/36T front chain ring with a 52/36T. Apart from moving the front mech up is there anything else I need to do? If I add a new longer chain will the rear mech need adjusting?

I have come from Sram AXS and have no idea how to set up shimano.

Cheers

[gruppetto]

You will need a longer chain when you add 6 teeth to the setup and normally you will not need to adjust the rear mech, if you want to be safe check the distance of the rear deraileur to the biggest sprocket with the b-screw afterwards.

[DaveS]

There's also a chain line problem. Grx is +2.5mm, compared to a road crank. You might have a FD adjustment problem.

[la85]

You will need a longer chain when you add 6 teeth to the setup and normally you will not need to adjust the rear mech, if you want to be safe check the distance of the rear deraileur to the biggest sprocket with the b-screw afterwards.

Thanks mate. IS there a measurement for the B gap? Ive had a look online but it only mentions no turbulence - which I am gathering is touching.

Sram have a bgap tool for sopecific cassette/rear mech combos.

Road would be a set measurement ?

Cheers

[gruppetto]

You will need a longer chain when you add 6 teeth to the setup and normally you will not need to adjust the rear mech, if you want to be safe check the distance of the rear deraileur to the biggest sprocket with the b-screw afterwards.

Thanks mate. IS there a measurement for the B gap? Ive had a look online but it only mentions no turbulence - which I am gathering is touching.

Sram have a bgap tool for sopecific cassette/rear mech combos.

Road would be a set measurement ?

Cheers

I just checked the manual for the RX815 RD and you are right, it is very unspecific (the latest DI2 road RD all come with a bgab tool). So I would gues you are fine if everything shifts well and the rear deraileurs pulley wheels have enough space towards the cassette.

[fa63]

Chain length is wrap around big-big, then add two links (or 1 inch). For B-tension, I go for as little as I can get away with. That means adjusting it such that it just stops making a grinding noise when shifting from second largest cog to the largest, then add another half a turn.

Sent from my moto g power (2021) using Tapatalk