Illinois Administrative Code
Title 92 - TRANSPORTATION
Part 428 - UNSAFE OPERATING CONDITIONS OF PASSENGER CAR TIRES
Section 428.20 - Unsafe Conditions of Tires
Current through Register Vol. 48, No. 12, March 22, 2024
A tire is considered to be unsafe if it exhibits any one of the following conditions or any combination of these conditions.
a) EXPOSED PLY OR CORD. A ply or cord is exposed when any portion of the ply or cord material can be seen by the person inspecting the tire. If parting or lifting the edge(s) of a crack, cut, snag, flap, or other tire surface interruption allows ply or cord material to be seen, the ply or cord is exposed.
b) BULGE, KNOT OR SEPARATION IN EITHER SIDEWALL OR TREAD AREA. These conditions indicate deterioration or internal damage of the tire structure. A bulge or knot usually indicates cord, sidewall, and/or tread separation, often accompanied by or caused by seepage of compressed air through the tire structure. A tire with any other condition that shows separation in sidewall or tread area or with any knot or bulge not accompanied by evidence of separation also shall be considered to be unsafe.
c) A MARKING THAT INDICATES THE TIRE IS NOT INTENDED FOR USE ON PUBLIC STREETS OR HIGHWAYS. Some examples are: "Unsafe for highway use", "Not for highway use", "For racing purposes only", and "For beach use." These or other markings might be applied by branding, cementing, cutting, molding, vulcanizing, or otherwise generating or affixing depressed or raised letters, numerals, or other suitable characters, into or onto a tire, either when the tire is manufactured or subsequent to manufacture. Other examples and descriptions are given in Appendix B.
d) ABSENCE OF A READABLE MARKING SHOWING THE SIZE DESIGNATION OF A TIRE OR ABSENCE OF A READABLE MARKING SHOWING THE RELATIVE LOAD CARRYING ABILITY OF THE TIRE.
Load Range |
Ply or Ply Rating |
Maximum Inflation Pressure |
B |
4 |
32 psi* |
C |
6 |
36 psi |
D |
8 |
40 psi |
*Pounds per square inch |
e) TREAD WEAR INDICATORS FLUSH WITH THE TREAD OUTER SURFACE IN ANY 2 OR MORE ADJACENT TREAD GROOVES AT 3 LOCATIONS EQUALLY SPACED AROUND THE CIRCUMFERENCE OF THE TIRE. A tire is considered to be unsafe when the flush condition exists:
Note: Tread wear indicators were molded into the bottoms of tread grooves in passenger car tires manufactured in compliance with federal requirements after July 31, 1968. They were molded into the grooves of many tires manufactured prior to that time. Tread wear indicators might be molded into the grooves of retreaded or recapped tires.
f) A TREAD GROOVE DEPTH OF LESS THAN 2/32nds (1/16th) OF AN INCH MEASURED IN ANY 2 OR MORE ADJACENT TREAD GROOVES AT 3 LOCATIONS ESSENTIALLY EQUALLY SPACED AROUND THE CIRCUMFERENCE OF THE TIRE, AT LEAST ONE OF WHICH IN THE JUDGEMENT OF THE INSPECTING OFFICER IS A LOCATION AT WHICH THE TREAD IS THINNEST, EXCLUSIVE OF TIE BARS OR TREAD WEAR INDICATORS. This rule is primarily for treads without tread wear indicators but, at the discretion of an inspecting officer, it may be used for a tread with tread wear indicators. When using this rule, do not measure on, or directly above, any tie bar or tread wear indicator.
g) REGROOVED OR RECUT IN ANY PORTION OF THE TREAD AND NOT MEETING ALL APPLICABLE REQUIREMENTS SET FORTH AND REFERRED TO IN SECTION 428.20(g)(2), BELOW.