04
Apr
Like the load index rating a tire speed rating is another shorthand way to reference how fast a tire can go in ideal conditions. The speed rating system was developed to help control the safe performance of tires at standardized speeds.
This is because light truck tires are often used on vehicles with dual rear wheels.
Tire speed rating index. Tire speed ratings are set by the tire manufacturers and are an indication of the tires maximum speed capability in ideal conditions. The tire load index rating communicates how many pounds a tire can safely carry. Put together they make up the service description.
Knowing this service description information is highly recommended whenever youre replacing Original Equipment OE or factory tires. A service description identifies the tires load index and speed rating. Service descriptions are required on all speed rated except for Z-speed rated tires manufactured since 1991.
The first two digits 87 S represent the tires load index and are followed by a single letter 87 S identifying the tires speed rating. Using a P19560R15 87S tire size as our example the 87S at the end of the size represents the tires service description. Tire speed rating or the speed indexsymbol specify the top speed at which the tire can carry a load corresponding to its load index under service conditions specified by the manufacturer.
The speed rating is identified as a part of the tire size designation or the tires service description together with the load index. The durability of a tire varies depending on the tires speed rating which refers to the maximum speed a tire can safely carry the vehicles weight and payload in ideal conditions. Tire speed ratings come in the form of a letter that follows the load index value of the tire.
The most common speed rating letters range from L to Y. To find your tire speed rating to reference the single letter at the end of your tire size this will be where youll find the speed rating for all tires manufactured since 1991. The most common tire speed ratings are L M N P Q R S T U H Y and Y letters that designate speeds ranging from 75 to above 186 miles per hour.
The speed rating system was developed to help control the safe performance of tires at standardized speeds. A tires certified speed rating is given a letter from A to Z ranging from 5kmh 3mph to above 300 kmh 186 mph. This rating system see below shows the top speed for which a tire is certified.
It does not indicate the total performance capability of a tire. Why Were Tire Speed Ratings Developed. The tire speed rating is the maximum speed tires can safely carry a load the original weight of your vehicle plus whatevers in it for a sustained amount of time in ideal conditions.
The rating is molded on the tire sidewall signified by a letter or two usually after the load index number. Tire load index or load rating is a numerical code on a tire sidewall which specify the maximum load the tire can carry at the speed indicated by the tires speed rating under certain service conditions - specified by the manufacturer. Definition of Tire Speed Ratings A tires speed rating is an indication expressed as a letter code on the tire sidewall of a speed the manufacturer expects the tire to be able to sustain over a long period of time without coming apart.
Light truck tires have two load indexes on the sidewall of the tire unlike passenger tires which only have one. This is because light truck tires are often used on vehicles with dual rear wheels. For example a light truck tire with a load index of 120116 means a load capacity for a single tire of 3086 pounds and a load capacity of 2756 pounds for two tires.
Speed Rating and Load Index Charts of Tires The numbers and letters engraved on a tire reflect among other things its load bearing and speed handling capacity. These are important specifications provided by the manufacturer and are a part of that tires rating. Home Uncategorized Speed Rating and Load Index Charts of Tires.
Tire speed ratings range from A the lowest to Y the highest. But the chart is not completely in alphabetical order. For example H is between U and V with the common perception that H stood for high performance at one time.
As manufacturers continue to add speed to their vehicles tire speed ratings evolve to match the speeds. The Speed Symbol is the maximum speed the tire is designed for. It correlates with Load Index as a STANDARD TIRE can carry even more if the speed is lower.
For Agriculture Radial Tires the most common Speed Symbols are A825mph B31 mph and D40 mph. If your tractor runs faster than 25 mph you will need the B or D rating. The available codes were SR 180 kmh 112 mph HR 210 kmh 130 mph VR in excess of 210 kmh 130 mph.
Tires with a speed rating higher than 300 kmh 186 mph are indicated by a Y in parentheses. The load rating is often included within the parentheses eg. The numbers give the load rating for the tire while the letter indicates the speed rating.
Using P21565R15 85H as an example the 85 gives the load index also called the tire ply rating and the H is for the speed rating which tells you the maximum speed at which you should use the tires. This speed ranges from 3 mph to 186 mph. Like the load index rating a tire speed rating is another shorthand way to reference how fast a tire can go in ideal conditions.
But rather than numbers it uses letters in mostly alphabetical order. More on that later The tire size in our example had a speed rating of Y. Tire Speed Rating Codes Here is the complete speed rating chart which interprets the alphanumeric code specified on the car tire wall into the maximum speed limit specification in miles per hour mph and kilometers per hour kmh.
Would you like to write for us. Well were looking for good writers who want to spread the word. Load Index The LOAD INDEX is a numerical code associated with the maximum load a tyre can carry except for loads at speeds above 130 mph 210 kmh see Table 22a at the speed indicated by its Speed Symbol under service conditions specified by Avon Tyres.