[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: 49CFR570.62]

[Page 184]
 
                        TITLE 49--TRANSPORTATION
 
                            OF TRANSPORTATION
 
PART 570--VEHICLE IN USE INSPECTION STANDARDS--Table of Contents
 
        Subpart B--Vehicles With GVWR of More Than 10,000 Pounds
 
Sec. 570.62  Tires.

    (a) Tread depth. The tread shall be not less than four thirty-
seconds of an inch deep on each front tire of any vehicle other than a 
trailer and not less than two thirty-seconds of an inch on all other 
tires.
    (1) Inspection procedure. For tires with treadwear indicators, check 
for indicators in any two adjacent major grooves at three locations 
spaced approximately 120 deg. apart around the circumference of the 
tire. For tires without treadwear indicators, measure the tread depth 
with a suitable gauge or scale in two adjacent major grooves at 3 
locations spaced approximately 120 deg. apart around the circumference 
of the tire at the area of greatest wear.
    (b) Type. Vehicles should be equipped with tires on the same axle 
that are matched in construction and tire size designation, and dual 
tires shall be matched for overall diameter within one-half inch.
    (1) Inspection procedure. Examine visually. A mismatch in size and 
construction between tires on the same axle, or a major deviation from 
the size recommended by the vehicle or tire manufacturer, is a cause for 
rejection. On a dual-tire arrangement the diameter of one of the duals 
must be within one-half inch of the other as measured by a gauge block 
inserted between the tire and a caliper.
    (c) General condition. Tires shall be free from chunking, bumps, 
knots, or bulges evidencing cord, ply or tread separation from the 
casing.
    (1) Inspection procedure. Examine visually for the conditions 
indicated.
    (d) Damage. Tire cords or belting materials shall not be exposed, 
either to the naked eye or when cuts on the tire are probed. 
Reinforcement repairs to the cord body are allowable on tires other than 
front-mounted tires.
    (1) Inspection procedure. Examine visually for the conditions 
indicated, using a blunt instrument if necessary to probe cuts and 
abrasions.
    (e) Special purpose tires. Tires marked ``Not For Highway Use'' or 
``Farm Use Only'' or other such restrictions shall not be used on any 
motor vehicles operating on public highways.
    (1) Inspection procedure. Examine visually for tires labeled with 
specific restrictions.