In Reply to: tire pressure posted by Smith on January 14, 2000 at 14:12:02:
:The only relevant information is:
1. The tire pressure
2. The width of the tire
3. The lenght of the tire surface contacting the ground.
Consider a tire that is 10 in. wide with about 2 inches contacting the ground. That's 20 sq. in. X 4 tires = 80 sq. in. At 30 lb/sq in. you can support a 2400 lb car(about the weight of the Z3).
Now consider a bicycle with 1 in tires and a 1 in contact length for a total of 2 sq in. You need to inflate these tire to 100 psi to support a 170 lb person + 30 lb bike.
Some monster tire with a huge contact surface need only be filled to a moderate psi to carry a 12 ton truck.