Tire Ply Chart & Information
The automotive industry relies on plenty of markings and numbers that mean something. Speed, weight distribution, and plenty of other aspects determine what a car is capable of. With the capabilities aside, these can also affect the safety and drivability of any vehicle.
Considering that tires are part of a car, the same principle applies here as well. If you’ve ever looked at the side of a tire, you probably noticed some markings that aren’t the brand or the model. Each marking corresponds to a tire’s certain ability.
The size is the most important aspect in most cases. It’s directly related to fitment, so it’s something that it’s easy to get wrong if you’re not paying attention. With the size aside, there are other areas that you should pay attention to, like the ply rating.
If you haven’t heard of this before, you’re in luck. In today’s guide, I’ll outline what a ply rating is and what does it mean for your tires.
What is a ply rating?
A ply rating, sometimes called load range, determines the maximum load a tire can carry when inflated to its maximum pressure. This is often mixed with the load index and, while they seem identical, they provide a different kind of information.
The idea of ply rating is from the older days when a tire’s ability to carry loads was determined by the number of plies it had. With newer technologies, tired don’t rely on that construction method, but the terminology remains. We use both load range and ply rating today to provide the same information.
The biggest issue here is the different markings that can confuse people. Considering that ply rating is a thing of the past, from now on I’ll use load range, which should also give you a better idea of the differences between load range and load index.
Passenger tires load range
The most common types of tires on the market are passenger tires. A common misconception here is that people think of these as tires for sedans of hatchbacks, but they also cover larger vehicles like CUVs and SUVs. The industry standard for this is called P-metric, which shows that we’re talking about a passenger tire.
Depending on the model, some tires will have the letter P before the size marking, which shows that it’s a P-metric one. These tires come in 3 flavors: light, standard and extra load. With that in mind, you also have different or no markings at all. Each one shows the maximum load pressure the tire can handle.
Load Range | Marking | Maximum Load Pressure |
Light Load | LL | 35 psi or 240 kPa |
Standard Load | SL | 35 psi or 240 kPa |
Extra Load | XL | 41 psi or 280 kPa |
There’s also a Euro-Metric standard, which is used for passenger tires, but uses slightly different values. To be precise, we’re talking about 1 psi higher values. These tires can be standard, reinforced or extra and extra load. The second two overlap a bit, which is clear from the identical maximum load pressure.
Load Range | Marking | Maximum Load Pressure |
Standard Load | SL | 36 psi or 250 kPa |
Reinforced/Extra Load | RF/XL | 42 psi or 290 kPa |
Extra Load | HL/XL | 42 psi or 290 kPa |
Light truck tires load range
Once we dive into the light truck tires, we see that the ply rating is still used. It’s the same as the load range, but sometimes we feel nostalgic, so we still use that. In this category of tires, manufacturers use lettering for the load range, which also corresponds to a certain ply rating.
With the LT tires (metric, flotation or numeric) we have letters from B to F that correspond to a ply rating ranging from 4 to 12. Regardless of which one you look at, that type of tire will handle a certain maximum load pressure. Another variable in this category of tires is the width of the tire.
Depending on the load range, a tire’s maximum load pressure will depend on the size as well. Tires that are narrower than 295 mm or 11.5 inches will handle more than their wider brothers.
Load Range | Ply Rating | Maximum Load Pressure (narrower than 295mm or 11.5″ inches) | Maximum Load Pressure (wider than 295mm or 11.5″ inches) |
B | 4 | 35 psi or 240 kPa | / |
C | 6 | 50 psi or 350 kPa | 35 psi or 240 kPa |
D | 8 | 65 psi or 450 kPa | 50 psi or 350 kPa |
E | 10 | 80 psi or 550 kPa | 65 psi or 450 kPa |
F | 12 | 95 psi or 650 kPa | 80 psi or 550 kPa |
Like with the passenger tires, we have Euro-metric tires for light trucks. With these, the load index comes into play, but you’re still getting the same information. Depending on the index, the tire will handle different load in terms of weight, which will depend on the maximum load pressure it will withstand.
Trailer tires load range
With trailer tires, things are very similar to the light truck ones. The load range ranges from B to E for ply ratings from 4 to 10. There’s isn’t a tire with a 12 ply rating, because trailers don’t need tires with that kind of capabilities.
Load Range | Ply Rating | Maximum Load Pressure |
B | 4 | 35 psi or 240 kPa |
C | 6 | 50 psi or 350 kPa |
D | 8 | 65 psi or 450 kPa |
E | 10 | 80 psi or 550 kPa |
Like before, with each ply rating or load range, you’ll know the maximum load pressure a tire can handle before things get out of hand.
Can you change the load range?
In the tire industry, there are dos and don’ts, and changing the load range of a tire is part of the don’ts. Car manufacturers specify these things for a reason, so that you can get the most out of your vehicle, while remaining safe.
When it comes to load range, things are similar to what I spoke about with load index or speed ratings. Depending on the situation, some people like to change things up with their cars. Here, going for a tire with a higher load range won’t be the worst thing in the world, but there’s no point.
A tire with a higher load range is tougher and more durable. In other words, the tire will be slightly heavier. The extra weight won’t make massive damage to your vehicle, but you will pay more and your gas mileage will degrade a bit.
While going for a higher load range isn’t problematic, going for a lower one is. We all want to save a few dollars on something, and people want tires with a lower load range for the same reasons. You should never go below what the car manufacturer says, because things can get dangerous quickly.
Conclusion
The load range or ply rating is the most confusing part of a tire’s specification. It provides a very important piece of information about what you should expect from a tire, but it’s also the part that sometimes gets neglected.
Being able to rely on your tires and their maximum load pressure is important, especially when we’re talking about situations where you’re hauling heavy cargo. The only thing keeping the vehicle on the road is a tire.
Therefore, you should always get a tire with the load range that the manufacturer specified. If you want to change something, go for a higher ply rating, but never go for a lower one.