Rough feeling drivetrain

[Scoobyshue]

Drive train feels a bit rough like a bearing has started to go. I've taken the back wheel out and the wheel and freehub bearings feel fine. The cranks seem to spin nice and smoothly and I've taken the chain guide off as I though it might have been that rubbing....it wasn't.

The chain is not overly worn. The 0.5 gauge drops through but the 0.75 doesn't. The shifts seem pretty crisp as well.

Any ideas what it may be? Could it be the chain. Its a 1x12 set up, narrow wide with an oval chainring?

One thing I did notice was the pivot bolt on the rear mech was really stiff. Would this cause the roughness?

Cheers all.

[G321]

My money would be on the chain, it's amazing how fresh a new chain can make gearing feel. Although it's odd you say it's not fully worn. for £30 it's worth changing once a year

[Scoobyshue]

I had everything apart at the weekend to properly clean, grease and checked all the bearings. Turns out it was the jockey wheels....bearings were shagged. Probably the cheapest fix on the drivetrain, so that's a result.