Just thought an update was in order, thanks to everyone for their contributions and advice.
Ended up changing the hub for a later type with a larger offset, also replaced the original aluminium sprocket for a Supermax.
Remarkable transformation - belt runs cleanly on the new sprocket, plenty of clearance to the tyre. Belt is now loosely tensioned (just so it doesn't slip on hard acceleration).
In my M3W I had become accustomed/de-sensitised to a whole array of mechanical noises and vibrations, from both the front and back. I suspect that my belt issues had been undiagnosed from new - judging by the wear on the wall of the tyre (only just done 3000 miles). By the time it came to me the MMC warranty had long passed.
I took the opportunity to drain and refill the BB (Millers EP140) at the same time
Now the only noise I hear from the rear is an acceptable mechanical 'whirr' from the BB and the hum of the belt. I have to say I'm really pleased, couldn't/wouldn't have done it without the encouragement of the TM forum and especially Calum's excellent write up.
Just one other question - has anyone given a thought to the fact that the Supermax overlay sprocket has one less tooth than the MMC standard one (64 to 65 I think).
Does this effect the gearing in a beneficial way?
Regards
Andrew
