[Blue Bomber Man]

Could make a sort of magnet clamp if you were crafty with it, just make sure it is more then strong enough to resist the shocks of a bumpy rode.

IMHO I would not switch from alloys to steels just for moondisks. Alloys perform significantly better than steel rims. Lowers mass, lower unsprung weight all translates to better handling and vehicle performance/acceleration with less draw on the engine. Additionally its rotational mass which means you are wasting that much more energy when braking with steel rims.