Pedaling is rough in the top 2 gears.

[Milzy]

My drive train is quiet & smooth until I'm into the 2 last small cogs on the cassette when in the big front ring.
It does seem to propel normally & I can't see the middle mech rubbing at all but it just sounds like an absolute bag of spanners. My MTB is suffering from the same problem.
Do I twiddle the little rear mech screw or the thumb turn one at the back? If so which way.

I have never had a service to fine tune things as I'd rather just learn & DIY it.

Kind regards.

 

[fossyant]

If its shifting correctly then don't start fiddling to much. It may need the bottom limit screw adjusting for the smallest sprocket. I'd suggest taking a good look at the jockey wheel and sprocket alignment from the back of the bike, low down when in those gears.

The chain and sprockets are clean aren't they.

 

[Milzy]

Yes clean sprockets & oiled but clean chain. I'll experiment with the screw tomorrow.

Thanks.

 

[lpretro1]

You shouldn't have to touch the limit screws - if you do and do not know what you are doing you could make it much worse. Likely just to need adjustment on the cable barrel instead.

 

[Milzy]

You shouldn't have to touch the limit screws - if you do and do not know what you are doing you could make it much worse. Likely just to need adjustment on the cable barrel instead.

Well the front mech 'was' rubbing when the jockey wheel was confirmed to be straight. The problem is the cable has snapped flush to the nut as Halfords made it too long. I've tried to do a front mech reset from the beginning & now I just can't pull enough through. So now I'll have a new cable with nipple fitted at the LBS tomorrow. I should have left it alone, but on the other hand I may as well have a new cable to adjust properly & be tuned perfect for coming sportives.
Always Something.