a tyre question

[b_hickman11]

Originally Posted by JapRulezz

just a second , forgive me for my car ignorance but how can 15' inch wheels have different diameters like 23.4 and 23.7 ? (doesn't 15 = diameter )

and how about filling the tyre with nitrogen instead of air which is better ?

Some tires can be the same size but have a different total diameter. It depends on the tread depth. Some tires come with a 9/32 tread depth while some others might have 10/32 or 11/32. Some may be even more than that.