When choosing wheels, you should consider several factors: what size and load, pneumatic or solid, or semi pneumatic, steel or plastic rims, hub length, bearing diameter, etc.

Generally: wheels include:

Tyres: different tyre threads, 2PR or 4PR

Pipe: natural or butyl pipe

Rim: steel or plastic rim, offset or centered. It is made of steel, powder coated or galvanized

Bearing: ball bearing, roller bearing or nylon/steel bushing