Passenger-type tire with 1.6mm wear bars in the tread.
A tire's tread depth is critical on rain wet pavement and snow. The depth of the tread is the way a tire pushes water from under the tire and channels it out so the tread can contact the pavement for traction. A tire with very little tread has a greater chance of hydroplaning, which may cause the driver to lose control of the vehicle. Only on dry pavement is less tread better for traction.
Passenger Car Tires
Tires worn past the tread life
New passenger vehicle tires generally have 10/32 (7.9 mm) to 11/32 inch (8.7 mm) tread depth. The depth is dependent upon the type of tread pattern and the utility purpose of the tire. The Uniform Tire Quality Grading (UTQG) rating is an indicator as to how many miles a tire should obtain before it reaches the wear bars. The UTQG rating should be used to compare one tire with another from the same manufacturer. Brand "A" may rate a tire that will not give the same mileage as Brand "B". UTQG is only an indicator, however, not a regulation.
Sport Utility Tires
Most new SUVs are equipped with passenger-type tires. Only the heavy-duty SUVs will be equipped from the factory with Light Truck (LT) tires, because of the vehicle's ability to carry a much heavier load. The same regulations for minimum tread depth apply to passenger tires and light truck tires on SUVs.
Winter Tires
Tires manufactured for winter conditions do not require the UTQG rating. The new winter tire will have a tread depth that is normally 11/32 (8.7 mm) to 13/32 inch (10.3 mm) deep. Winter tires also have wear bars at the same depth as standard highway tires.
Large Vehicle Tires
There is a significant variation in large vehicle tire tread designs and tread depths. The same wear bars are in over-the-road large truck tires. It is strongly suggested by NHTSA that these tires be replaced when the tread depth reaches 4/32 inch (3.1 mm) for safe stopping in various weather conditions.
Wear Bars
All tires manufactured for highway use are regulated to have wear bars in the bottom of each tread groove across the tire. The wear bar is a raised portion of the tire's tread that indicates there is 2/32 inch (1.6mm) of tread remaining. When a wear bar is even with the top of the tread, in any groove, it is time to replace the tire.
Tags: tread depth, tire tread, tire with, UTQG rating, wear bars, have wear, have wear bars