Hi All, been struggling for two days now to get the tyre on my shiny new WM1/20"stainless rim to go on straight. Tyre is a new Avon ribbed Speedmaster,( 20") and no amount of tyre soap/pulling/shouting will get it to come fully up out of the rim well and sit on the rim properly.Both sides have a "sunken" bit 6-8" long and I have pumped it up to over 55psi to no avail several times now.I am beginning to think the rim is oversize??? or the tyre is undersize??????-(less likely i would have thought, Avon have been a long time in the tyre business) I have had "reluctant" tyres before, but always managed to seat them eventually, not this one. Any Ideas ?, cheers, Bob.