My brother happened to be driving behind me and noticed my rear right wheel had a wobble.
Bolts were tight as hell (much more than the 120nm recommended) I basically had to jump on the tyre wrench to get them out and it knacked the ends of the bolts up. I got my hands on some better conditioned ones as I didn't fancy getting re-using them.
Anyway...I put a set square against the tyre the closest I could and span the wheel and looked from behind straight at it. It was clear that the distance changed at a certain part of the wheel.
Swapped it with my space saver wheel, fine. Then the other rear wheel, seemed fine (very very slight movement/wobble but it doesn't have any balance weights on it).
The bad wheel does appear to be balanced. there were no dents/flat spots that were visible with the tyre on.
Does this sound like a buckled wheel?