These arrived yesterday and I've spent pretty much most of the night putting them together and trying different tyres on them. They're sold by drastic sports on ebay, and are fantastic. They're heavy, solid and well designed (you can get the wheel nut wrench down in to the opening unlike my hot racing ones.)
Nice thick heavy rings Notice the bevel on the outside and the grooved inside? These pull the beads right into the rim. Even mashers hold with 2 screws. They pull the tyres in real well too.
with Proline Flat irons
Proline Hammers
My tuber
More to follow. I've got a second set for the mashers. They'll be going on in the near future, but from what I have tried, they grip enough to run 2 screws in the rings only.
Weights and dimensions to follow when I can find my ruler!!!