(Eli5) Why do Buses & Trucks use 2 skinny wheels put together on each side of the axle? Instead of just using one fat wheel?

Question

(Eli5) Why do Buses & Trucks use 2 skinny wheels put together on each side of the axle? Instead of just using one fat wheel?

In: Engineering

Answer 1

Big wheels mean wide thicc rims. Thicc rims not cheap to make, waste money. Nobody wants to buy extra unused thicc rims.

So use normal rims, normal tyres, side by side. Save money and save materials/metal.