1961 NASCAR International Rule Book Specifications NASCAR Grand National Championship Circuit Section 21-31 -- Wheels

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

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

c. Hub caps must be removed.

d. Any stock appearing steel hubs may be used.

e. Heavy duty lug bolts may be used.

f. Rim Widths: See Grand National Specifications Chart. Fifteen or 14 inch wheels permitted, but all four wheels must be same size at all times.