Preferably US. Diameter and also wheel depth.
Have you heard? The bird is the word.
There really is not acommon" size anymore; more vehicles are being produced with ridiculous looking and extremely expensive wheels that are getting larger each year. The choices are 13 14 15 16 17 18 19 20 21 22 and perhaps even larger sizes........very dumb !!!
Wheel or tire? Wheels(Rim) there are many sizes, cars have wheel sizes ranging from 12" - 22", 12" not very common and 18" to 22" are usually aftermarket but are showing up more, 17" is becoming very popular to the auto companies. But as for the most common I would have to say the 15", it's been pretty standard for more than a quarter of a century. For tires, the sizes are in mm's (ie 225/60/15) this tire has a width of 225 mm's from sidewall to sidewall, the height of the sidewall is 60% of the width or 135mm's and fits a 15" wheel. The most common tire size I think would be in the 195/75 to 225/60 range, and usually the larger the rim the shorter the sidewall height.
