Tyre Load Rating Guide
When you are shopping around for a new set of tyres for your vehicle, it is important that you check out the tyre load rating of your existing tyres - or the set you mean to replace.
Determining just how much weight or load your tyre can handle is a great place to start when planning to purchase a set.
Inadvertently buying new tyres with the wrong load rating is hazardous - too much weight might damage it and cause an accident.
This guide hopes to explain what tyre load ratings are exactly and why it is important in ensuring our tyres - be it new or old - stay safe.
What is Tyre Load Rating exactly?
The Tyre load rating is the maximum load or weight a moving tyre, at the fastest speed allowed, when properly inflated, can carry.
The rating (or index) is applicable for just that one, individual tyre - and not all four attached to the vehicle.
In most cases, each of the four tyres found on a vehicle should have identical load ratings.
A numerical value represents the load ratings. The higher the tyre's load index number, the greater its load-carrying capacity.
For example: A load index of 65 is equal to 265 kilograms - that is the maximum load-bearing capacity of that tyre, while a load index of 105 is equal to 925 kilograms.
Most passenger vehicle load indexes range from 62 to 126.
On some light trucks, the load index consists of two ratings divided by a forward slash. Here is an example: 104/101. Two ratings are necessary because light trucks often have dual tyres on their rear axle. The first number indicates the load-carrying capacity if the tyre is for a single-wheel rear axle, and the second number applies to a dual rear axle.
The reason the second load index number is less even though the second pair of tyres support it is to maintain reserve capacity if one of the tyres fail. Were this to happen, it would leave the sole remaining tyre the load supposed to be supported by two tyres.
How is Tyre Load Rating determined?
Tyre load ratings are set by the tyre manufacturers themselves since they design and produce the tyre.
Once the tyre company identifies the type of tyre, they will produce and for what class of vehicle it is for, they can start working out what the tyre load rating will be.
For original equipment tyres, tyre companies work with the car manufacturer to get the actual weight of the new vehicle. This information will help figure out what the tyre load rating will be.
Tyres shoulder the weight of the car, its passengers and cargo plus the weight of the force that gets added when everything starts to move. This substantial total amount of weight is why tyre engineers must know how much the car will weigh on its own as they work out the tyre's load rating.
When they have determined the rating, the tyre engineers will run tests to see if they gave the tyre the correct load rating or not.
Tyre load ratings are indicated by a set of numbers that range from 0 to 279. Each number corresponds to the maximum weight or load a tyre via a two or three-digit number.
Where can I find my Tyre's Load Rating?
You can easily find the tyre loading rating of your tyre on the tyre itself. It is part of the tyre code that you see on the tyre sidewall. The tyre code is the series of alphanumeric symbols on the tyre. It identifies the car's classification, size (tyre width, sidewall height, diameter size), tyre load rating, and the tyre speed rating.
The load rating is located after the diameter measurement and before the tyre's speed rating on the sidewall.
Aside from the tyre sidewall, you can also find the load rating information on the driver-side door jamb. It's located on the tyre placard placed there by the vehicle manufacturers. This placard identifies the number and location of seating positions and the total load capacity for occupants and luggage. Original Equipment tyre sizes and the vehicle manufacturer's recommended cold tyre pressure are also included on the tyre placard.
Your vehicle's manual will also have the tyre load information. You can also get in touch with the car company themselves or check online - but make sure the information is valid.
Why is a Tyre's Load Rating Important
Tyre Load Ratings are important because it prevents drivers from installing the wrong tyres, protecting the general population from accidents that are sure to happen when a tyre is overloaded.
An overloaded tyre is one that is carrying too much weight - more than it was designed to handle. It is also a tyre that is running with lower pressure than what was indicated by the manufacturer. Using a tyre with less pressure causes friction and the heat to increase internally, eventually leading to a blowout and destroying the tyre.
It is vital to check with your manufacturer on what capacity tyres to fit on your car. Apart from the dangers of overload, your insurance can become void if you have an accident while driving on tyres with the wrong load index.
Tyre Pressure & Tyres Load Ratings
It is important to remember that a tyre's load rating is accurate when the tyre is correctly inflated, with the prescribed amount of tyre pressure. Regularly check your tyre's air pressure so it is still within the proper air pressure levels.
What happens if I use Tyres with the wrong Load Rating
It is EXTREMELY DANGEROUS to use a tyre with a load index lower than what your car's manufacturer prescribed.
1. Tyres will wear out faster, wasting money and requiring you to replace them earlier.
2. You'll be literally driving around in a car accident waiting to happen. Too much load causes tyre blowouts which can be fatal not just for you but anyone else out on the road with you.
3. Your tyres - and vehicle - will lose driving stability and your ride will no longer be comfortable.
4. In case of an accident, your insurance company may refuse to cover your vehicle if it was using tyres not recommended by the car manufacturer.
Fitting tyres with a lower than recommended rating AND driving around with them is illegal and punishable by law.
You are risking not only your life - but those of your passenger and other road users.
It is possible to use a tyre with a higher load rating than recommended by your vehicle's manufacturer.
But are there any advantages to it?
Using a tyre with a higher load rating will provide enhanced cornering capabilities as well as increased stability and control, especially at higher speeds.
However, since it is still not the correct load rating, it won't be as comfortable to ride in the vehicle, and there will be a higher rolling resistance, causing the car to consume more fuel as it fights the friction.
Tyres with higher load ratings are usually more expensive as well, causing you even more money.
Using tyres with the proper load ratings guarantees a safer driving experience for everyone.
Tyre Load Index Table