I checked over a friend's M3W today and came across this:
The whole of the rear wheel compartment (under the plastic tray) was covered in sticky tar-encrusted stones, presumably from a newly resurfaced road. Unfortunately one of them had got stuck to the underside of the drive belt and over time has worked its way through the belt. We have removed the stone and are encouraged that the belt hasn't split either side of the hole. In an ideal world the belt would be replaced, but (as that's a pig of a job) we have decided to monitor it for the time being.
A great advert for having a rear mudguard fitted!
