A tire speed rating refers to the maximum speed a tire can endure without compromising safety, performance, and longevity. There are several different speed ratings out there which means that you should carefully choose the rating that fits your car, and your usage scenario the best. You also need to keep in mind that there are some benefits and drawbacks to each specific speed rating.
Both the S speed-rated tire and the T speed-rated tire are really closely matched which means that the differences between these two shouldn’t be substantial. However, we are going to mention the differences anyway in order to help you decide what is right for you. As such, S vs T Speed Rating tires, which ones to get, and why?
S vs T Speed Rating
An S speed-rated tire is one that can easily endure all the stresses associated with continuous rolling up to a maximum of 112mph or 180kph. This means that an S speed-rated tire should have no problems offering everything the manufacturer promised up to these speeds. If you go above these speeds, you are going to face certain consequences we are going to mention down below.
On the other hand, a T speed-rated tire is one that is rated for up to 118mph or 190kph which isn’t really a substantial difference. Therefore, these two types of tires should offer a fairly similar performance overall. There are some differences between the two when it comes to performance, longevity, comfort, and winter capabilities, but these are so small that they are not worth getting into.
Why Are Speed Ratings Important?
A car tire is designed to fulfill an incredibly important set of roles. It needs to distribute the entire weight of the car, it needs to be able to respond to the driver’s inputs immediately, and it also needs to be safe, refined, and long-lasting. In order for a tire to satisfy all of these aspects of driving, a tire needs to be built in a certain way and it needs to be maintained in a certain way.
Not only does a tire need to be built for a specific type of car, yet it also has to have all the corresponding standards stamped right onto the tire so the driver can always know what he/she can and can’t do. A speed rating is one of those systems that communicate to the driver how fast those tires can go without making those tires suffer.
It is an essential message that needs to be heard, otherwise, you are risking a bunch of unwanted consequences, some of which can even end up deadly. Speed ratings aren’t just about how fast a tire can go, but they are also about how well the tire copes with other aspects of driving, especially traction, stopping ability, comfort, longevity, and handling.
What Happens If I Exceed A Tire Speed Rating?
If you go over a tire speed rating for a few moments, nothing much is likely to happen. The truth is that you can probably go over a tire speed rating a hundred times, and the tire is not likely going to suffer. The problem arises when you exceed a tire speed rating for an extended period of time, such as while traveling at highway speeds for tens of minutes or even hours.
The reason why a tire is rated for a certain speed is that that tire is able to withstand all the stresses associated with continuous rolling at that speed. While the tire turns, it generates friction which generates heat. If such friction is really intense, the heat build-up is also going to be intense. If too much heat builds up and it does not go down, such heat is going to start eating your tires.
When this happens, you are risking a few potential issues, all of which are serious. The least dangerous thing that can happen is that your tire lifespan is likely going to suffer which means that your tires are not going to last as long as they should. This certainly isn’t good, but it is nothing compared to what can happen in the worst-case scenario.
The worst care scenario can result in tread separation, tire bulging, a broken tire belt, or even a full-on tire blowout/explosion. This can very easily be deadly, especially at speeds over 112mph or 118mph.
Can I Fit Tires With A Higher Speed Rating On My Car?
There is absolutely no reason why you can’t fir tires with a higher speed rating, but only if you carefully satisfy all the other tire metrics. If you are having trouble understanding how to read tire size codes and what they all mean, click here for a quick rundown. The best thing you can do is just pick the same tire that came with your car, but with the all-necessary upgraded tire speed rating.
Can I Fit Tires With A Lower Speed Rating On My Car?
You sure can. Even though some might argue the reasoning behind downgrading a tire speed rating, it actually makes even more sense to downgrade as opposed to upgrading it. A lower tire speed rating usually comes with its own set of pros and cons, and some people prefer the benefits you get with a lower speed rating as opposed to those you get with a higher speed rating.
What Are The Benefits Of High-Speed Tire Ratings?
High-speed-rated tires are designed and built primarily for supercars, sports cars, race cars, high-end luxury cars, project cars, and all other cars that are focused on speed and performance. Tire manufacturers know that something like a Y speed-rated tire is almost 100% reserved for supercars. Therefore, a high-speed-rated tire is also going to come with lots of other benefits typically associated with these types of cars.
These benefits are:
- Better acceleration – High-speed-rated tires come with different rubber compounds and different sidewall stiffness levels, all of which are designed to help put the power down in a more continuous and linear manner.
- Better stopping power – This is more or less tied to better acceleration because these tires grip the road better, no matter if you are accelerating or braking. Therefore, the stopping distances associated with these tires are usually better.
- Better handling and cornering – Changing direction is when the tires endure friction the most which means that heat build-up is extremely relevant while cornering. Because high-speed-rated tires resist heat and friction better, they also corner and handle better.
What Are The Benefits Of Low-Speed Tire Ratings?
At first glance, it may seem like low-speed-rated tires are worse in every way, but the reality is much different. All the benefits typically associated with tires with a lower speed rating are the complete opposite of what you get with high-speed-rated tires.
These benefits are:
- More comfortable drive – Low-speed-rated tires tend to be more comfortable overall, not just only in regard to ride quality, but also in regard to the noise. Therefore, these tires are built for those who just want to cruise as opposed to those who enjoy racing.
- They last longer – It is no secret that tires that typically go slower also tend to last longer. These tires simply don’t endure the same stress levels which are directly tied with how long these usually outlast high-speed-rated tires.
- Better in the winter – As mentioned above, high-speed-rated tires are designed to endure high temperatures which is not something you need during winter. A good winter tire is designed to endure low temperatures. As such, a low-speed-rated tire should, in theory, be better during the winter.
Where Can I Find A Tire Speed Rating?
A tire speed rating can usually be found stamped directly onto the sidewall of the tire. In order to find it, you ought to look for the tire code. A tire code typically reads something like this: P265/55 R19 89 H. The very last letter in this sequence refers to the tire speed rating which in this case is the letter H. The letter H corresponds to the tire being able to withstand speeds of up to 130mph.
Why Should I Go With S And T Speed-Rated Tires?
These tires are typically designed for standard commuting cars such as sedans, estates, SUVs, crossovers, and other family cars. These represent somewhat of a middle ground within the speed rating chart which means that S and T speed-rated tires should be able to withstand all the speed you need without hampering tire longevity, comfort, and winter driving. However, don’t go thinking that these tires are performance champions.
At the end of our “S vs T Speed Rating” article, we can wholeheartedly say that these two speed ratings share pretty much the same set of drawbacks and benefits. The S speed-rated tire should in theory be a bit more comfortable, better in the winter, and it should last a bit longer.
On the other hand, a T speed-rated tire should be a bit more performance-oriented tire. However, as these are only separated by a 6mph difference, we can say that these are almost identical. Either way, be sure to consider both if these speed ratings work for you.