Why are car tyres filled with air and not solid rubber?
Generally, as Mr Dunlop knew, this allows for alterations in air pressure for different vehicles and bikes, so that the optimum can be achieved for different circumstances. Obviously, racing cars, different types of road cars, road bikes, mountain bikes, etc, have to have the right pressure for the job. This provides for increased comfort, especially over rough surfaces, and for increased safety. Many early vehicles did indeed have solid rubber tyres (and even metal and wood on ancient carriages). They had the benefit of not having punctures! Oddly, the wear and tear was greater than for air-inflated tyres. Incorrectly inflated tyres also have greater wear. There are still specialist means of transport with solid tyres, even today. Some kiddies’ bikes have them, as do some land-speed record ‘cars’. These are normally suitable only for smooth surfaces; otherwise, the ride would be unbearable and damage would soon occur. I have refrained from giving sources, as there are thousands of his
