[Code of Federal Regulations]
[Title 49, Volume 5]
[Revised as of October 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR570.9]

[Page 178]
 
                        TITLE 49--TRANSPORTATION
 
                            OF TRANSPORTATION
 
PART 570--VEHICLE IN USE INSPECTION STANDARDS--Table of Contents
 
         Subpart A--Vehicles With GVWR of 10,000 Pounds or Less
 
Sec. 570.9  Tires.

    (a) Tread depth. The tread on each tire shall be not less than two 
thirty-seconds of an inch deep.
    (1) Inspection procedure. Passenger car tires have tread depth 
indicators that become exposed when tread depth is less than two thirty-
seconds of an inch. Inspect for indicators in any two adjacent major 
grooves at three locations spaced approximately equally around the 
outside of the tire. For vehicles other than passenger cars, it may be 
necessary to measure tread depth with a tread gauge.
    (b) Type. Vehicle shall be equipped with tires on the same axle that 
are matched in tire size designation, construction, and profile.
    (1) Inspection procedures. Examine visually. A major mismatch in 
tire size designation, construction, and profile between tires on the 
same axle, or a major deviation from the size as recommended by the 
manufacturer (e.g., as indicated on the glove box placard on 1968 and 
later passenger cars) are causes for rejection.
    (c) General condition. Tires shall be free from chunking, bumps, 
knots, or bulges evidencing cord, ply, or tread separation from the 
casing or other adjacent materials.
    (1) Inspection procedure. Examine visually for conditions indicated.
    (d) Damage. Tire cords or belting materials shall not be exposed, 
either to the naked eye or when cuts or abrasions on the tire are 
probed.
    (1) Inspection procedures. Examine visually for conditions 
indicated, using a blunt instrument if necessary to probe cuts or 
abrasions.

[38 FR 23950, Sept. 5, 1973, as amended at 39 FR 12868, Apr. 9, 1974; 39 
FR 19781, June 4, 1974]