Might be a long shot, but I'd check the bottom bracket too. Had a noise coming from (what I thought was) the rear of my bike. Sounded a bit like the derailleur cage was clipping the spokes a tiny bit, and because the noise was most noticeable when I was in the lowest gears at the back, it seemed to add up. However, when I checked it out, the cage was well clear of the wheel. Had the back wheel trued and tensioned, as I thought it could be that creaking and groaning. Still the same!
Working gradually through a process of elimination, and desperation, I moved along the bike to the crank area. Cranks were tight enough, pedals spun freely, but when the BB seemed a bit stiff. Whipped off the cranks and I could barely turn the BB axle by hand. Got the adjustable wrench on it, which got the thing turning, but it felt rough.
Replaced the whole unit with a Shimano UN55 (I know...... old technology, square taper axle) for £9.49 from
Wiggle, fitted it..........and "hey presto"...... silent bike!!
I'm now convinced I thought the sound was coming from the rear of the bike as the noise of the rough BB bearings was transmitting through the taught chain (which by coincidence will be at its tightest when in the torque inducing lower gears) and leading me to look in the wrong place initially.
Might not be the issue with your bike, but perhaps worth a look. I know how annoying a mystery noise can be, so worth covering all the bases......even if you think they can't possibly be related.
