Question

why the truck and motorbus has much wider tyres

Answer 1

to provide much area to hold the vehicle because small tyres can easily burst with the weight

Answer 2

truck and motor bus have wider tyres because wide tyres reduce the amount of pressure exerted on road .. wide tyre have large surface area for pressure distribution and thus can prevent damaging of road
If the tyres of huge load carrying vehicle were not wide then they would apply huge pressure on road and thus road may get damaged




I hope it helped ! ! ! ;-)