How to Read Tire Markings

There's no doubt that tires are among the most important elements of a car as choosing the proper tires for your vehicle can sometimes make the difference between leaving the roadway and having an accident or staying on the road without any damage. We're sure car enthusiasts can easily differentiate summer tires from winter variants and vice-versa, but how many of you can actually understand the odd markings written on the tires? Because we're sure you'd like to know what every symbol means, here are the most common notations on today's tires.
First of all, manufacturer or brand name. It is usually the biggest marking on the tire, being embossed straight on the center, so there's absolutely no chance to miss it.

Secondly, tire size, speed rating and load index (in our example it is 295/40 ZR 20 Extra Load). Note that these markings may vary by tire type, meaning that notations appearing on a high-speed variant are a bit different than the ones embossed on regular tires.

Then, there's the tire construction (radial tubeless in our photo). The radial construction is the most common version used on today's tires as they are capable of providing advanced rigidity plus better handling on various types of roads. The tubeless inscription tells us the tire does not require an inner tube, which provides better safety at higher speeds and better performance, including braking and acceleration.

The pressure marking and the maximum allowed load are usually placed on the inner edge of the tire (Max Load 1060 kg (2337 lbs), Max Inflation 330 kpa (51 PSI) in our picture). Obviously, these two notations vary by tire type, dimensions and several other factors.

Last but not least, there's that weird DOT HWJM N5H8 code that represents the North American Department of Transportation compliance symbols and identification numbers. Basically, these numbers tell you the city the tire was manufactured in. For example, the two first letters after the DOT marking denote the name of the city: in our case, HW stands for Barum Continental, Otrokovice, Czech Republic.

Beside all these letters/symbols/codes, you may also find a number of other details, such as the country where the tire was manufactured (Czech Republic for us), safety warnings, which let you know a bunch of hazards that may cause “serious injury”, plus temperature rating, traction rating or tread-wear rating.

Now getting back to tire dimensions, each of these numbers actually denote a feature of the tire, regardless if we're talking about width,
height or speed rating. So, have a look at the adjacent photo and read the following explanations:

1. the group of three digits (295 for us) represents the width of the tire in millimeters.
2. the next two numbers (40) represent the sidewall height and is usually expressed as a percentage (of the width); in our case, it measures 118 mm.
3. the ZR group, which usually appears on high speed tires, has two meanings: the Z letter means the tire allows the car to run with more than 149 mph (240 km/h) while the R shows us it is a radial tire.
4.the last two digits unveil the rim diameter – 20 inches in our photo

In addition, you may find a bunch of other markings such as a two digit number, which usually represents the load index – extra-load in our case, plus a capital letter, with H the most common, representing the maximum speed the tire can support (H represents 130 mph/210 km/h).

And because we're talking about speed markings, here are the meanings of all notations:

M - 81 mph (130 km/h)
N - 87 mph (140km/h)
P - 93 mph (150 km/h)
Q - 99 mph (160 km/h)
R - 106 mph (170 km/h)
S - 112 mph (180 km/h)
T - 118 mph (190 km/h)
U - 124 mph (200 km/h)
H - 130 mph (210 km/h)
V - 149 mph (240 km/h)
W - 168 mph (270 km/h)
Y - 186 mph (300 km/h)

For the complete list of DOT codes showing you the country where the tire was manufactured in, check out the attached PDF file.
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 Download: Tire Manufacturer Codes (PDF)

About the author: Bogdan Popa
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Bogdan keeps an eye on how technology is taking over the car world. His long-term goals are buying an 18-wheeler because he needs more space for his kid’s toys, and convincing Google and Apple that Android Auto and CarPlay deserve at least as much attention as their phones.
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