Most people in the US are too confident when it comes to tire quality. They often limit their judgment on the appearance itself, forgetting about the tire characteristics and ratings. It reaches to the point wherein car makers question whether it is the car’s malfunctions that cause majority of the road accidents or the consumers’ incompetent skill in choosing the vital car parts.
If you have not known yet, all the tires available in the market are subject to the compliance of the Vehicle Safety Standards or its equivalent organization. The tires must pass all the needed requirements before they can be made available for purchase. Each tire must meet the required standard for traction, tread, and temperature as well as the tire speed rating. A little bit of knowledge about tire ratings may not be enough, but it is better than not knowing anything at all.
You may not immediately see the relevance of choosing the appropriate tire rating of your car, but its importance is a great factor to maintain safety throughout the entire drive. Knowing your tire ratings will help you decide the maximum speed your tire can handle and maintain as well as its heat tolerance, and many more.
The tire rating utilizes letters in the rating. With the rating which ranges from A to Z, it is best to know what these ratings stand for.
For temperature related ratings, we have the A, B, and C rating. The A rating indicates the tire’s capacity to withstand the heat which is an important quality of tires that you should consider. Heat buildup is among the greatest threats to your car’s tires. The tires have to be tested longer in order to test if they achieved the A or B rating. While it is being tested, it is also essential to test them at a higher speed. If the result of the test is high, this means that the tires can handle heavy loads and hot temperatures. On the other hand, rating C can be achieved if the tires passed the test against the steel roller. It is usually done at 50 mph which lasts for about 2 hours, 75 mph for additional 3 minutes, and another 30 minutes for every 5 mph added.
In general, rating A is considered to be the highest rating when it comes to temperature while rating C means that the tire has low resistance to heat and does not have the ability to dissipate heat. Some of the causes of heat buildup are under inflation, excessive loading, and excessive speed.
This particular traction test is merely based on straight-ahead braking traction test and does not measure the turning traction.
Traction is an important feature of the tires. Without traction, your car will not be able to accelerate efficiently. It is the force that allows motion to be possible through the help of a dry friction between a tangential surface and a body. It is also known as the tractive force.
Each tire has either a traction rating of C, B, A, or AA. It is the traction rating of AA that is considered to be the best so far while the tire with a traction rating C means a poor and low traction performance. The traction test is done through a controlled skid test which is usually on a wet surface. The test involves both in concrete and in asphalt surface.
It is a comparative rating which is based on the tire’s wear rate. The rating is tested through the controlled conditions under the government specified test course. The tread wear rating is done with the purpose of being able to tell how long the tire’s rubber tread lasts.
The performance of the car is often dependent on their actual use. A tread wear rating of 200 gives you the idea that the tire has twice the life of a tire with a rating of 100.
The speed rating of your car indicates the defined speed the tire can handle and maintain in order to have safe drive. The higher the rating is, the better control and handling you have at a higher speed; it also indicates that the tire can withstand excessive heat. A highly rated tire also means that it can be easily handled even at a slower speed.
The speed rating test of the tires is based on the test designed by tire engineers; this includes running the tires at 6.2 mph steps with a 10 min augmentation. This is continually done until the defined speed is met.
There are several test rating results for the tire speed test; however, only four of them are commonly used. The four basic ratings designated for the tire’s sped test are the H, S, T, and Z rating. Below are the definitions of the said four ratings.
The H rating of the tire’s speed test means that the tires can safely sustain the speed of 130 mph. The H means that the tire has high performance. It is also important o take note that speed rating H does not follow the G rating; it is between the ratings U and V instead. This kind of speed is usually common in vehicles like coupes and sedans.
The S rating, on the other hand, means that the tire can sustain up to 112 mph speed. Most people would still feel uneasy and consider the 112 mph an absurd and unsafe speed.
The T rating of the tire’s speed test certifies that the tires are safe to use in the maximum speed of 118 mph. It is usually common in vehicles like minivans and family sedans.
The Z rating is considered to be the highest rating for a tire speed test. It entails that the tires are safe to use in 149 mph or more. In this case, the Z rating does not have a constant mph equivalent but considers the 149 mph as its lowest. This type of speed rating is often found in sports car and race cars.
When checking the tire speed rating of your car, please note that the speed, temperature, traction, and tread wear are rated separately. It means that a tire with high rating in speed test may have a low rating in temperature and tread wear tests.
To ensure that you are using the right tire ratings in your tire, make sure to check the manufacturer’s specifications. It is also advisable to use the tires with the same rating in all tests.