Could be the tyres, differential, gearbox. wheel bearings
Bald tyres are tyres where the tread has been worn of in use and if this is the case then the tyres are not same (and illegal) to use. There are tyres made without a tread (for racing cars), these are not called bald tyres, they are called "slicks" and instead of a tread the surface of the tyre is made to be sticky in use.
Pneumatic tyres, tyres containing pressurised air, were invented in the nineteenth century. The first pneumatic tyres were made by a man named Robert William Thomson, from Stonehaven in Scotland, in 1846. He called them 'Aerial wheels' and fitted them to horse drawn carriages in London. The technology of the time couldn't produce rubber thin enough to make these tyres practicable, so he returned to using solid rubber tyres. The first practical rubber tyres were developed in Belfast, Northern Ireland, in 1887 by John Boyd Dunlop; who made pneumatic tyres for bicycles.
Regal Tires are made by a company called Apollo Tyres.
If the tyres would not be round they will not move.
Front tyres 30psi Rear tyres 34ps1 Fully loaded 5 passengers with luggage Front tyres 30psi Rear tyres 38psi This is for Tyres 185/60/R15
how does friction help car tyres?
Assuming you're talking about the tyres... The tread on the tyres channels water away from the wheels - allowing the tyres to grip the road better than if the tyres were completely smooth.
because if the tyres are of metal the will slip
Normal pneumatic tyres do not work correctly without air. Run flat tyres do, so do solid tyres.
The advantages of using Continental tyres are that they are cheaper than some other tyres. Another advantage of using Continental tyres can be that they last longer than some other tyres.
There are many retailers and websites that can offer customers scooter tyres for sale. Some of these companies that offer scooter tyres are Scooter Tyre Store, My Tyres and National Bike Tyres.