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If you have ever looked closely at your tires or even purchased tires online, you have noticed that tires have distinct speed ratings imprinted on them, amongst many other imprints. Typically, these ratings are delineated by two letters, such as HR, ZR, etc. What do these ratings mean and how do they affect you, the driver? One might assume that all tires are the same: they are rubber and round. However, the diversity of tires (and companies for that matter) on the market mirrors the milieu of cultures and peoples around the world. Even though there are many tire manufacturers out there, the rating system for tires is universal; hence, it applies to every tire made. Specifically then, let us take a closer look at tire ratings and what they mean to you, the consumer.
What Is The Point Of A Tire Rating?
Besides the vast quantities of information found on tires, a distinctive speed rating is printed on the tire with the letters M through Z. Part of the reason why speed ratings are affixed to tires has to do with the famous super highway, the autobahn, which is located in Germany. For those out there who are not familiar with the autobahn’s “rules of the road,” there are a series of lanes that have their own distinctive top speed posting. The top speed posting is not a speed limit, but rather, the minimum speed in which motorists are required to travel in this lane. What we would term as excessive speeding, is the norm on the autobahn, as mid triple digit speeds are common.
When a man named Adolph Hitler built the autobahn in the 1930s, tire science was not exactly what it is today. Your vehicle may have had the potential to hit an incredible top speed, but your tires may not have been able to handle the top speed for long without blowing out and causing a catastrophic accident. Tire manufacturers caught on to this after a while and began to manufacture different grades of tires for different types of vehicles. For example, would you rather have a tire with a speed rating designed for a Pinto on a Ferrari or a tire with a speed rating suited for Ferrari? In reality, it is as simple as that.
Speed Ratings Explained
Many of us in Canada and the United States do not exactly travel to and from place to place at break neck speeds like those found on the autobahn. However, we do have access to the multitude of different tires with different speed ratings. In other words, it is up to you (and your coffer) if you want to travel in excess of the posted speed limit if your tires can support the speed. If you look at one of your auto’s tires, you will see something similar to 225/50R16 (89S). What we are looking at here in this article is the letter found within the parenthesis, the S (some tires do not have the speed rating in parenthesis). With that said, here is the system in which tires are rated for speed (top speeds):
- M: 81mph or 130 km/h
- N: 87 mph or 140 km/h
- P: 93 mph or 150 km/h
- Q: 99 mph or 160 km/h
- R: 106 mph or 170 km/h
- S: 112 mph or 180 km/h
- T: 118 mph or 190 km/h
- U: 124 mph or 200 km/h
- H: 130 mph or 210 km/h
- V: 149 mph or 240 km/h
- Z: in excess of 149 mph or 240 km/h plus
- W: 168 mph or 270 km/h
- Y: 186 mph or 300 km/h
You will notice that the Z rating is for speeds in excess of 149mph or 240km/h, but there are two different ratings below it. When Z rated tires were introduced, there was a lack of street legal autos that were able to obtain speeds that high or higher. Hence, it was believed that future vehicles would be unable to or would be manufactured so that they could hit those break neck speeds. However, as we know now, there are countless vehicles that can easily zoom past 149mph or 240 km/h, especially autos classified as exotic cars. This is why the W and Y ratings were eventually introduced.
Not that there are many out there who are concerned with Y rated tires (our vehicles typically come with H rated tires), but if you see a rating on a tire such as 285/35ZR19 (99Y), that means that the tire has been tested in excess of the above-mentioned top speed.
Buyer Beware
If you ever search an online tire seller’s website, you may notice that they may have a bargain or two in concern to Z and above rated tires. In most cases, unless you prefer these tires or your vehicle calls for such a tire, stay away from them. If you look above, as the top speed increases, the longevity of the tire decreases. This is why most vehicles are equipped with stock H rated tires; no one really needs to go that fast and they last longer than say, V or Z rated tires. On the other hand, if you purchased a sports car that came stock with Z rated tires, you can most definitely “downgrade” to a cheaper (in most cases) and longer lasting H rated tire. This is, of course, unless you prefer break neck speeds and speeding tickets!
Sources:
Tirerack.com
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