Re: Wheel drone/hum noise diagnosis
I find this all very interesting. My major complaint about our 147 (apart form shocking ride which must be my age at fault) is the abysmal road noise which seem to come form the rear. I wouldn't characterise it as like hub bearing noise. I've had hub-like noises in the past only for them to disappear completely with fresh tyres, which I put down to either tyre resonance that just happens to sound like hub bearings or an alignment of tyre cavity and hub resonances, one exciting the other.
So far as these alignment measurements are concerned, they are symmetric, that's a good start. I donlt have much faith in results form certain national chains. The last time I went in to one of them all that changed was the steering wheel azimuth - it got drunker!
From the thumbnails you now seem to have negligeable front toein/out, like the spec that's been posted. On the other hand, if I read the diagramme correctly, the spec calls for half a degree of toe-in at the rear while you now have nearly half a degree of toe-out? Your cambers are 'low' in relation to spec (large in negative sense) which could accentuate wear on the inboard side, especially with large tyre sections. So far as Caster is concerned, might not half a degree asymmetry in 3deg just be enough to cause it to pull, and also cause some uneven wear?
Lets be honest, most cars drive round with these sorts of issues, I'm always a little afraid too much discussion can 'talk up' something minor into a lot of worry and big bills. It's worth being doubly sure the toe-ins are within spec and then keep an eye on wear for a few miles. I don't think an Alfa is ever going to be a tranquil ride.
Doesn't say that in the manual