Why are there two different sizes of tires

Does anyone know why motorcycles have a larger tire in front than in the rear?

it improves handling as the larger wheels ride bumps better. If you ride anything with a 10" wheel you will know what i mean. Also the tyres last longer as an added bonus

KurtPerthWa Thanks for the imput on the wheel size. It makes sense especially tire wear.

Another
reason to have different sized tires is that the rear tire has to carry
a heavier load since bikes are balanced with greater weight to the rear
end. Also the rear tire needs a bit more rubber on the road since that
tire carries the power load from the engine so a larger contact patch
helps keep the wheel from spinning. You could put wider smaller
diameter tire on the front too but it would transmit more vibration and
bumps from the road due to it's smaller diameter and if it was wider
like the rear the steering effort would be greater.