Shifting issues..

[19Dogger87]

Recently purchased a pair of superstar components jockey wheels to replace the ones on my ultegra 6800 rear mech, since swapping them I have been having major issues with shifting into the largest 2 sprockets on the cassette. I've set the B screw correctly and have no issues in the other 9 sprockets, however, when shifting into the largest 2, it looks like the chain is coming off the side of the upper jockey wheel and pulling the mech forward. The B screw appears to be set correctly and gears are indexed, hence, I can't see any reason why this would happen. Its fine on the stand and shifts as it should...

The only difference I can see with them is the down have the same amount of play as the original Shimano ones. I've not had a chance to swap them back over (fitted yesterday and found the issue, stripped and reset today and the issue remains)... Next step is to replace originals, however, before I do, has anyone else had similar issues?

Cheers!

[Deefor62]

Have you checked whether you’ve got them fitted correctly ie top and bottom as they do differ. They are normally marked top/bottom and have an arrow showing direction they turn.

[19Dogger87]

Exactly what I thought, but there's no markings on them at all - hence, I assumed they were both the same

[anonymous-user]

is the chain routed through the derailleur properly - specifically in the cage between the two jockey wheels

[19Dogger87]

Yeah, routed correctly too! Literally stumped. Going to swap them back out if nobody has had the same issues before. Its not worth ripping the derailleur off for. They will be going back

[Jimbo.]

The play in the top jockey wheel is known as the “guide pulley” and, as the name suggests, helps with the shifting. It’s meant to have some play. The lower tension pulley doesn’t have any play by design, if I recall correctly. If everything else is untouched and nothing was dinged in the fitting (cage straight, indexing unchanged etc) then there’s your problem.

[19Dogger87]

Yeah I think you are right, I will be sending them back for a refund. I put the original Shimano ones in and back to smooth shifting with no issues.

Its a shame as I had heard a few people say good things about these aftermarket ones.. interested to see what they say when I email.

Cheers for everyone's input