Last updated on January 4th, 2024 at 11:19 am
According to many drivers, tire ply is still the deciding factor of the tire’s weight-carrying capability. This is not the case since radial tires have taken over bias ply tires.
Bias ply tire construction is different. Multiple fabric plys are laid at alternating angles (usually 30-45 degrees), and the more plys are there, the more capable the tire becomes of lifting weights.
In 2024, it is an outdated technology; it has low durability and less fuel consumption but is better at off-road and heavy-duty rides, which is why some off-road drivers appreciate bias-ply construction.
Now, as most of the passenger car tires are radial construction, the weight and plys number do not apply here.
In radial construction, there is usually a fabric ply laid perpendicular (90 degrees) to the direction of the center. The construction of these belt packages, including fabric ply, steel belts, and inner layers, determines the load index of the tire.
So, before you identify the tire’s maximum load, you first need to identify the construct of a tire, which we will explain in this article.
We will talk about ply ratings, how you can identify your tires’ weight limits, and what tires’ rating should be bought based on your vehicle.
So, without further ado, let’s start with finding a ply of your tire.
Table of Contents
Determine the Ply rating on the tire
Bias ply tire
In bias construction, you can find a number of fabric and steel plys are involved in the tire on the tire’s sidewall. This number usually lies between 4 and 16 plys, and it tells that this is how many plys are installed inside this tire.
The higher the number, the more load index or load limits of the tire. It’s simple in bias ply tires, but it’s quite complicated with radial tires.
In radial tires, instead of actual plys, numbers or indexes are assigned to each ply’s numeric number. Which you can see in the below chart.
Even though you find a ply rating on the sidewall of the radial tire, it’s not the actual number of ply; it is a capability of the tire equivalent to a certain number of ply.
For example, your tire has an XL or SL rating on the sidewalls, which, in other words, is 4-ply constructed. This is not true; it does not mean that XL or SL tires have 4-ply layers; it means that one or two-ply layers are as strong as 4-ply and can carry equivalent weights.
Difference between ply rating and load index
As described above, Ply ratings are an alphabet assigned to the fabric plys equivalent load capacity. On the other hand, load indexes are a standard assigned to the load capacity in lbs.
Both of these terms determine the weight and load capacity of the tire, but ply ratings are also important in determining the recommended PSI of a tire.
So, ply ratings tell you about the air pressure and ply capacity but can not identify the actual weight limits of the tire. Tire load indexes identify exactly how much a tire can carry with the recommended air pressure.
The load indexes are also written on tire sidewalls almost always before speed ratings. The number could vary between 1 and 150, depending on your tire capacity. The higher the number, the more capable your tire will be against weights.
Ply Rating on Different Tires
Passenger tires generally do not use the ply rating system explicitly. Instead, they are described using terms like radial or bias construction.
For example, a tire might be described as “P215/65R16 95H,” the R before rim diameter states that it is a radial tire, and P at the start states it is a passenger tire, and it is become a standard that all radial passenger tire will have a standard ply rating which is SL or XL (4 ply)
Light Truck (LT) and Special Trailer (ST) Tires
Similar to passenger tires, LT and ST tires have transitioned away from using ply ratings. Instead, terms like load range are commonly used. LT tires often have load ranges such as C, D, or E, which indicate the tire’s load-carrying capacity.
For example, an LT tire might be labeled as “LT265/70R17 E,” or “ST265/70R17 E,” where “E” is the ply rating which is 10 ply.
Load Range “C”: Commonly used for light-duty trucks and SUVs.
Load Range “D”: Typically used for heavier-duty trucks and SUVs.
Load Range “E”: Designed for heavy-duty trucks and larger SUVs.
What Tire ply should you go for
Ply Rating For Towing
For towing, a higher ply rating is better. Usually, people tow with light trucks, so find a tire that comes with E ratings, which is more than enough for balancing the weight without destroying the tread of the tire.
With that, also consider the load index of the tire, which is more important when it comes to towing heavy weights. Go with the highest possible load index that you can find in your tire size.
12 Ply vs. 10 Ply Tires
The ply rating alone doesn’t tell the whole story about a tire’s strength or performance. However, a 12-ply tire is often associated with a higher load range compared to a 10-ply tire. In practice, a 12-ply tire might be designated as a Load Range “F,” while a 10-ply tire might be Load Range “E.”
Whether a 12-ply tire is better than a 10-ply tire depends on your specific needs and the load requirements of your towing or truck application. If you frequently tow heavy loads or carry substantial payloads, a higher load range (such as Load Range “F”) may provide the extra strength needed for the job.
How To Check Ply Rating
Checking ply ratings is straightforward; just look at your tire’s sidewall. If you are driving an LT or ST tire, there will be an alphabet written after speed rating, that is your ply rating. Now, search that number on the internet to find the exact ply rating in numbers.
what’s the difference between tires of the same size but different load ranges
Different ply ratings mean different PSI and air pressure. So if the tire is in the same size but in a different ply rating, one of these tires will be better at handling weights than the lower ply rated tire even if they are the same in other metrics.
Will a tire with a higher Load Range last longer?
A load range does not have anything with the longevity of a tire. However, if you drive with heavy loads on a low-load range tire, it will wear off earlier than a higher-rated tire. So durability is not about load range; you have to drive with recommended weights. Otherwise, the tire will wear off earlier.
What do the letters (XL, SL, E) mean on tires?
These alphabets are the ply ratings nowadays. Unlike old times, when there was exact ply written on the sidewall, with the radial tire, these numbers have assigned ply, and based on that, you can identify what ply equivalent your tires are.
Ply Rating and Sidewalls Ply are related?
Yes, these are the same concepts, and just like bias ply construct to radial construct, there is no actual ply given. If the tire would be 4 ply rated and bias construct, the sidewall will also have 4 plys; however, in radial construction, just like tread, there is a considerate ply rating, and not actually the number of ply layers.
Tire ply rating is another important aspect of tire size and is really important if you are looking for a tire for specific needs. You can find tire ply ratings on sidewalls, and if it is not written in the case of passenger and radial tires, the internet is the best source to find the right ply ratings and every other tire size aspect. So, next time you buy tires, also consider ply ratings, as they can become very useful, especially if you are into towing kinds of stuff.