Why Split Rim Wheels?

Spilt rims are multi-piece wheels, where the tyre is held in place by a locking ring. Split rims are not normally used on cars or light vehicles. ... Failure of multipiece (Split Rim) wheels can result in violent separation, the explosive release of high pressure air and the ejection of component parts.

When did they stop using split rims?

There is almost no chance of having a split rim. The NTSB outlawed these in the 1960's. This is the famous "exploding tire" urban ledgend. It wasn't the tires that blew up it was the split rim failure.

Are split rims illegal in US?

The old style of split rims are illegal in all 50 states.