Q vs S Speed Rating

Last Updated July 8, 2022

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Our cars are designed for a wide variety of purposes which means that some of us love fast cars, some of us love comfortable cars, and some of us like going off-road, but pretty much everyone wants a safe car as that is unnegotiable. As such, it is essential for everybody to choose the perfect set of tires for their car as the tires translate every driver’s input onto the road.

Q vs S Speed Rating

A tire speed rating is one of those essential metrics that need to be on point if we want to make the most out of our cars. This “Q vs S speed rating” article is going to help you understand how different speed ratings work, why you should go for a high-speed tire, and why you should stay away from it.

Q vs S Speed Rating

A Q tire speed rating is able to withstand all the stresses for speeds up to 100mph or 160kph. This means that a Q speed-rated tire should not exceed these speeds for an extended period of time as that can either shorten the lifespan of the tire or sometimes even destroy it completely.

An S speed-rated tire is one that can endure speeds up to 112mph or 180kph which means that it typically performs better than a Q speed-rated tire in every way. However, a higher speed-rated tire is known to last a shorter amount of time, it is also usually not as comfortable, and it suffers greatly during wintertime.

What Is Tire Speed Rating?

A tire speed rating is a system designed to indicate a specific tire speed capability. Because different tires are designed and built differently, there are many distinctions between a low-speed-rated and a high-speed-rated tire. You ought to educate yourself about all the differences in order to be able to choose the perfect speed rating for you.

You can find a tire speed rating stamped directly onto the sidewall of the tire as a part of the tire sizing code. A tire size code reads something like this: P 265/65 R17 112S. The very last letter in this code corresponds to the tire speed rating which in this case is S (112mph or 180kph). If you want to see a chart with all the available speed ratings, click here.

Without a specific tire speed rating, all tires would be designed in the same way which means that you will not be able to choose the tire that fits you best. In order to understand this in more detail, we are now going to tell you what are the usual differences between a high-speed-rated and a low-speed-rated tire.

What Are The Differences Between High Speed-Rated And Low Speed-Rated Tires?

  • High speed-rated tires perform better
  • High speed-rated tires handle better
  • High speed-rated tires withstand heat and friction better
  • Low speed-rated tires usually last longer
  • Low speed-rated tires are better during winter
  • Low speed-rated tires are more comfortable

Do High Speed-Rated Tires Perform Better Than Low Speed-Rated Tires?

Besides the obvious maximum speed difference between low and high speed-rated tires, we also need to mention that high speed-rated tires perform better in pretty much every scenario that does not include winter, ice, or snow. Because these tires are designed for sports cars and supercars, they tend to come with groove and thread designs that help the car put the power down better while also helping the car stop at a shorter distance.

High speed-rated tires are typically wider in most cases because those are also the benefits you can with performance tires in general. A wider track enables better weight distribution and it keeps the car level during cornering. A standard performance tire tends to be rated for very high speeds which means that it benefits from pretty much all the pros you get from a performance tire.

Do High Speed-Rated Tires Handle Better Than Low Speed-Rated Tires?

When it comes to handling, cornering, and weight transfer, high speed-rated tires are indeed better than low speed-rated tires. A higher speed rating does not only enable you to go faster, yet it also enables you to go faster through corners. As high speed-rated tires endure heat and friction stress a lot better, they perform better at virtually all speeds up to their maximum rated speed.

This means that high speed-rated tires are all-around more responsive, more continuous, and more confident-inspiring while changing direction. However, there are some high-performance tires out there that aren’t rated for higher speeds which more or less nullifies these differences. Be that as it may, they are fairly rare and unpopular.

Do High Speed-Rated Tires Withstand Heat And Friction Better Than Low Speed-Rated Tires?

The main difference between high speed-rated and low speed-rated tires is how well they cope with the stress you get from continuous high-speed rolling. The faster the rolling, the more friction is being generated which raises the surface tire temperature exponentially. A Q speed-rated tire is designed to be driven up to 100mph because it can’t endure the stresses associated with speeds higher than that.

On the other hand, an S speed-rated tire is better as it can endure heat and friction levels generated by speeds up to 112mph. This also means that an S speed-rated tire manages heat better at virtually all speeds, not just post 100mph.

Do Low Speed-Rated Tires Last Longer Than High Speed-Rated Tires?

A purpose-made performance tire is one that offers you the best performance credentials you can get from a piece of automotive rubber. In order to achieve this, the tire needs to be designed specifically for performance which means that the engineers who designed it didn’t really prioritize how long the tire can actually last.

Moreover, a high speed-rated tire can’t last as long as a normal tire because driving at higher speeds simply shortens the lifespan of a tire. More heat dissolves the rubber compounds that make the tire at a faster rate. If you pair that with overall softer construction, a high speed-rated tire is not going to last all that much.

Are Low Speed-Rated Tires Better In Winter Than High Speed-Rated Tires?

High speed-rated tires are designed to cope with high-temperature levels which is the exact opposite of what is needed from a good winter tire. Therefore, opting to make the tire withstand higher temperatures better immediately affects how well the tire copes with colder temps. Therefore, a low speed-rated tire is likely to perform better than a high speed-rated tire during the winter.

Are Low Speed-Rated Tires More Comfortable Than High-Speed Rated Tires?

Low speed-rated tires tend to be designed with stiffer contact patches, but the sidewalls tend to be softer as opposed to a high speed-rated tire that is designed the other way around. Because the sidewall is the piece of the tire that supports the weight of the car and absorbs the impacts caused by road undulations, low speed-rated tires do tend to be more comfortable.

Furthermore, low speed-rated tires aren’t focused on other aspects of performance as much either which means that low speed-rated tire grooves and thread design should emit less road noise which inherently also makes them quieter.

What Happens If I Exceed A Tire Speed Rating?

If you briefly exceed the speeds rated for your tires, nothing is likely ever going to happen because, for the tire surface heat to increase, you have to exceed maximum tire-rated speeds for an extended period of time. So, if you go 10-20mph over the rated speeds, your tires should be just fine. This is often the case with overtaking.

However, if you exceed your maximum tire-rated speed and you continue driving over the threshold, your tires could suffer in more than one way. For starters, you are likely to notice rubber-burning smells coming from your tires which are expected if you drive in an aggressive manner. Moreover, you are also risking damaging your tires, sometimes even destroying them completely.

The worst things that can happen are likely tire blowouts, tire belt cracking, tire sidewall cracking, or even tread separation. If any of these happen while driving at higher speeds, you are in great danger of losing control and going off the road which is why you should never exceed a tire speed rating if that is not completely and utterly necessary.

Conclusion

At the end of our “Q vs S Speed Rating” article, we can easily see that there are some benefits and drawbacks to each of these. A Q speed-rated tire is obviously slower, yet it usually lasts longer, is more comfortable, and is better during winter time. On the contrary, an S speed-rated tire performs better, handles better, and endures heat better.

You ought to pick your specific tire speed rating depending on which car you drive and how fast and aggressive you usually drive. Q speed-ratings are mostly reserved for family cars while S speed-ratings can often be seen on some sports cars as well. If you want to know more about specific tire speed ratings and how they compare, be sure to click here.

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