How to Read a Passenger Tire

The markings on a passenger tire and it's construction can be a little confusing at first glance, but in the diagram below, we have attempted to sort out the mystery. The staff at any of our Superior Tire & Auto Centres will be pleased, of course, to help you with any questions that you may have -- whether they be about tires or vehicle performance.

Reading and understanding the information on passenger tires is essential to wise shopping. There are substantial differences in tires that may or may not be reflected in the price of the tire and the buyer should be aware of these. Most information moulded into the tire casing is done either by federal law or by industry standards. In addition to displaying Department of Transportation (DOT) quality grades for treadwear, traction, and temperature, all passenger car tires must conform to federal safety requirements.

  1. The Tire Brand's Name & Model... the registered brand name of the tire (i.e. Toyo Versado,  Michelin's Harmony , Yokohama TRZ, , Pirelli P6 Four Season, ,Bridgestone's Blizzak, etc.).
  2. Country of Origin.... the country of origin is imprinted only when the tire is made outside the U.S.A.
  3. Maximum Load Specifications.... this refers to the load per wheel the tire can safely handle ( in our example tire '92' would equate to 1389 lbs. per tire).
  4. Maximum Inflation Pressure.... this figure (usually between 30-44) represents the maximum cold-air inflation pressure that is considered permissible for the tire.
  5. Safety Warning.... this warning is a tire industry approved statement advising of the danger of disregarding overloading and underinflation recommendations.
  6. The Uniform Tire Quality Grading System (UTQG) .... this system involves three factors reported by the manufacturer for their tire.
    1. Treadwear ... the base rate is 100 indicating 15,600 miles of treadlife or 25,000 kilometres. Each manufacturer rates their tire in comparison to their own base rated tire and establishes their individual rating guide.
    2. Traction ... this measures the tire's relative ability to stop on wet road surface. The 'B' rating is midpoint in an A,B,C braking-force grading system, with 'A' representing the best rating.
    3. Temperature ... a tire's resistance to generating heat and its ability to dissipate any heat that is generated is also graded on an A,B,C scale, again with A being the highest.
  7. Size of Tire.... these numbers indicate the size as explained on our drawing. It also depicts the aspect ratio (i.e. our example shows '75'). This is a measurement of the tire's height from the rim to the surface of the tread in comparison to it's width. Our tire then has a height that is 75% of the tire's width.
  8. Construction materials.... the number of plies and the type of reinforcing materials used in the construction of the tire.
  9. Miscellaneous.... the sidewall also lists whether the tire is tubeless, radial or bias construction, the manufacturer's mould type and serial number, the manufacturer's name and whether it qualifies for performance in mud and snow with the 'M&S' designation.

First, some basics. The side of your tire contains a wealth of information. Just look at the sidewall and all the information you need to identify the product is there. We've created an example for you below using a tire with the size of P195/75SR14.

How to read a passenger tire

MODEL: Model of the tire (e.g. P6 Four Season ). You need to know the model since each manufacturer makes a wide variety of models.

TYPE: Tubeless is the type of tire. It means that there is no inner tube inside the tire. Almost all tires today are tubeless, but some still require an inner tube.

ARROW: If an arrow is on the sidewall of your model of tire then it indicates that the tire is unidirectional (not all tires are unidirectional) and must be mounted on a wheel so that the arrow points toward the front of your car. The tire must roll in this direction in order to perform properly in wet weather.

P: P means Passenger tire.

195: 195 tells you in millimeters how wide your tire is. It is also called the section width.

75: 75 tells you how tall the tire is. The number is actually a percentage of the width of the tire. In this case the tire is 75% as tall as it is wide. (This is also called the profile of the tire, or the aspect ratio.)

R: R simply means radial.

14: 14 tells you the diameter of the wheel that this tire is intended to fit.

92: 92 is the load index. The final number and letter on the tire sidewall after the size designation represents the service description, or load index and speed rating. The load index is an assigned number ranging from 0 to 279 that corresponds with the load carrying capacity of the tire; that is, how much weight it is certified to carry at maximum inflation pressure. The rating can be matched against a load index chart to determine corresponding maximum weights. A load index rating of 88 indicates a maximum load of 1,235 lbs.

Other symbols that you might find on the sidewall of other types of tires are:

LT: LT stands for "light truck" tire

SPEED RATING: The speed rating is a letter which indicates the range of speeds at which a tire is certified to carry a load. Each tire is assigned a rating from A (lowest) to Z (highest). There is one notable exception: the "H" rating falls out of sequence between "U" and "V," and is used for tires certified for speeds up to 130 mph. The Q rating is the lowest commonly used for passenger cars. A "V" -rated tire is certified up to 240 km/h or 149 mph.

Below is a list of speed ratings along with the corresponding speeds they represent. Remember, the speeds are test speeds, not recommended speeds.

  • Q – Up to 100mph or (160 km/h)
  • S – Up to 112mph or (180 km/h)
  • T – Up to 118mph or (190 km/h)
  • U – Up to 124mph or (200 km/h)
  • H – Up to 130mph or (210 km/h)
  • V – Up to 149mph or (240 km/h)
  • W – Up to 168mph or (270 km/h)
  • Y – Up to 186mph or (298 km/h)
  • Z – Up to 149mph and over or (240 km/h and over)

Two important notes when considering speed rating:

  • We do not recommend downgrading the speed rating of your tires. This may result in poor handling and unpredictable steering. However, if you want better cornering response, there is no problem installing a higher speed rated tire on your vehicle.
  • Never mix and match tires with different speed ratings on your vehicle. This will cause serious problems with the handling of your vehicle.

At every Superior Tire Auto Fitness Centre, we will make it our business to satisfy you in every way possible - with the latest in equipment, helpful and competent personnel, a large in-stock selection of brand name tires, wheels and parts - and with the finest guarantees in the business.

We're Here to Help

The staff at your Superior Tire & Auto Centre will be happy to go over any sidewall readings that pique your interest or that require further explanation. There are other Super/Tips Bulletins showing speed ratings, load indexes and aspect ratios that may also be of interest to you. And rest assured.... we will guarantee that you and your vehicle will have the right tire for all your driving and safety needs.... with the best warranties available in Canada.