1960 NASCAR International Rule Book Specifications NASCAR Grand National Championship Circuit Section 21-29 -- Tires

a. No knobs, powergrips or speedway treads allowed. No cross grooving allowed. Standard treads only. Racing rubber permitted. For tire sizes on all models consult allowable sizes on specifications chart. For speed trials and record attempts, tire size must be standard and approved by NASCAR officials.

All four tires must be the same size as to actual measurement.

b. Experimental tires are not eligible unless approved by NASCAR.