Swapping FSA 46/36 Crankset for 6800 50/34

michaelstewart1984

Hi all,

I'm looking to swap out my existing 46/36 crankset (FSA Omega + BB AL86 bottom bracket) for an Ultegra 6800 50/34 teeth setup (+ suitable BB). The rest of the drivetrain is currently 105 5800, so I expect the 6800 crank to be compatible.

Just wondering what else I may need to do after this, as I've seen varying reports. I'm expecting worst case scenario of:

1) Adjust / replace front mech (was going to upgrade 105 front mech to Dura Ace at some point anyway).
2) Adjust chain length / replace chain.
3) Re-index rear mech.

Can anyone confirm this is the case, or otherwise shed any light on this? Are there any other potential problems I should anticipate?

Thanks!

svetty

michaelstewart1984 wrote:

Hi all,

I'm looking to swap out my existing 46/36 crankset (FSA Omega + BB AL86 bottom bracket) for an Ultegra 6800 50/34 teeth setup (+ suitable BB). The rest of the drivetrain is currently 105 5800, so I expect the 6800 crank to be compatible.

Just wondering what else I may need to do after this, as I've seen varying reports. I'm expecting worst case scenario of:

1) Adjust / replace front mech (was going to upgrade 105 front mech to Dura Ace at some point anyway).
2) Adjust chain length / replace chain.
3) Re-index rear mech.

Can anyone confirm this is the case, or otherwise shed any light on this? Are there any other potential problems I should anticipate?

Thanks!

No need to change front mech IMO. Might need slight height, limit stop and cable tension adjustment though.

keef66

+1 ^

You should have to lift the front mech so it clears the teeth on the new big chainring, which in turn will mean faffing with the front mech cable. Limit screws will only need attention if the chainline of the new crankset is different from the old.
If your chain was as short as it could be on the old setup, you could need a longer one for the new.

Rear mech shouldn't need to be touched.