Mystery wheels and tyres

Hi while moving some of the agricultural equipment for the “at home” show at Shuttleworth tomorrow the college offered us their old wood saw, when we collected it the wheels are definately not agricultural in origin does anyone have any ideas? the Tyre is marked A.M. 950 – 12 and the wheel has a couple of stamps SERIAL NO R5 4519S and DRG NO AM 2016

[ATTACH=CONFIG]247067[/ATTACH]

Any ideas?

Cheers

Steve