Question

trucks and buses have double tyres in the rear end. why?

Answer 1

the tyres which are at he rear end are called as rear tyres  ...these rear tyres helt the buses and trucks for a good grip when breaks are applied

Answer 2

Because the engine of most vehicles is at front ends, they are heavier at the rear . however, with buses and trucks, the weight at rear is so much that their single tyres will burst. hence to provide more support and stability, they have tyres at rear ends. these tyres also are of special quality rubber which can withstand a lot of force without bursting. it is specifically made for heavy vehicles and cant be found on cars and bikes