The American way
of tyre

In the USA, tyre codes not only show the speed and conditions of use but also provide information about wear, traction and temperature

Home road The American way
of tyre
The American way
of tyre

Reading [the information on] a tyre can be a longer operation than you think. In addition to the tyre dimensions, with regard to the rim and construction techniques, as well as the make and model, the tyres are also covered with different symbols and writing. Many of these codes are required by law in some countries, such as the United States, but contain detailed information on the tyre, and which is still very useful to learn to read. 

The American way of tyre

One of these is the UTQG. It is an acronym which stands for Uniform Tyre Quality Grading. It is a code reserved only for the United States market, being used by Department of Transportation, but since most of the tyres that we find in Europe are also exported to America, it is easy to find this sign also in our region. It applies to all road vehicles, with the sole exception of tyres with specific tread profiles for off-road and snow, the spare wheel and now quite rare tyres for 12-inch wheels. 

What the tyre says
The UTQG codes consist mainly of three different elements that can be found on tyres with the English terms ,” tread wear”, “traction” and” temperature”. "Tread wear" essentially means the degree of tread wear, which is indicated by a numerical code that the US Department obtained through a comparison with other tyres within the same criteria. Under complete absolute equality of conditions for example, a 200 grade tyre is potentially capable of lasting twice as long compared to one with a grade 100. Of course, this value should not be confused with an evaluation of the tyre tread life, as this is also affected by many other factors such as driving style, average load, everyday use and characteristics of the roads travelled. The second code is "traction". This can be expressed with the letters or four "scores". AA, A, B and C (from the highest to the lowest). This is an assessment derived from a braking test in wet conditions carried out by the Department under the same conditions for every case. The result is, in fact, similar to the rolling resistance as a concept, but applied to the braking ability on wet surfaces, without taking into account any steering, acceleration or aquaplaning. Finally there is a last index, relating to the temperatures. It is the degree of heat-resistance of the tyre derived from its operation at speed. Letter "A" refers to tyres that can dissipate heat effectively above 115 mph. Grade B indicates the same thing, but between 100 and 115 mph. Finally there is the grade C, with heat dissipation at between 85 and 100 miles. Any tyres that cannot get at least a "C" score in this category may not be sold in US territory.

The tyre identity card
Finally, looking closely at your tyre, you may also notice a number of other alphanumeric codes having two, three or four elements. This is manufacturing information for the wheel in question. DOT represents the acronym of the American Department of Transportation. After this, we find other signs as you can see in the photo. Codes XN, 8M and N668 refer to the factory of production and are unique for each factory. O n the other hand, the final 4-figure number refers to the date of production. In our example we see 3315, which is the 33rd week of 2015 (namely between 10 and 16 August). There are also specific codes in this case for the USA market, which are not considered Europe, as there are already different indications.

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