1970 NASCAR International Stock Car Racing Rule Book NASCAR Grand National Championship Circuit Section 20-28 -- Wheels

a. Wheels must be reinforced. General appearance must not be changed.

b. All four wheels must be same size and diameter and same offset at all times.

c. Hub caps must be removed.

d. Any stock appearing steel hubs may be used.

e. Heavy duty lug bolts must be used.

f. Fifteen or 14 inch diameter wheels permitted, but all four wheels must be same size at all times. Maximum rim width 9 1/2 inches.