How Big are the rims on a car from nascar?

May be...

15's

15 x 9.5 inch rims,

5 x 5 bolt pattern

From Marty Smith @ nascar.com....
According to the Nextel Cup rulebook, Goodyear Racing Eagles must not exceed a maximum sidewall measurement of 13.2 inches when placed on an approved wheel that measures 15 inches tall by 9.5 inches wide. Oh, and for good measure, 60 lbs of air pressure is used during the measurement process.

The rules require 15 inch steel rims.

just wanted to know how big the rims are on those cars

They have 110in wheelbase (Sprint Cup Series)

105in (Nationwide Series)

112in (Camping World Truck Series)hawaiian miles flowers