The tyre’s load index determines the tyre load capacity - the maximum weight the tyre can handle at a time. It’s crucial to check the tyre load rating especially when planning to transport heavier loads or when selecting new tyres for your car. Knowing the tyre’s parameters always helps to avoid safety risks on the road.
What is tyre load rating?
The tyre load rating defines the maximum load of a tyre moving at the maximum permissible speed. The load rating is expressed by a two or three-digit number and is located on the tyre sidewall. The manufacturer sets the maximum load capacity of the tyre, taking into account the most loaded axle of a vehicle.
The load capacity is extremely important for road safety and is always considered together with tyre speed rating.
Tyre load rating vs. total car weight
By knowing the maximum weight one tyre can carry, we can easily calculate the maximum total weight of our vehicle.
If the tyre load rating is 91T, it means that the load on the tyre shall not exceed 615 kg.
If you multiply the load (in kilograms) estimated for one tyre by the number of tyres in your vehicle, you get a value slightly higher than the total maximum weight of the vehicle.
If you plan to choose replacement tyres in a different size than those recommended by the manufacturer, you should choose tyres with a load rating specified in the manual of your car.
Do not install tyres with a lower load rating than recommended by the manufacturer.
How to get a proper size and load rating of replacement tyres
The following example will give you practical hints on how you should match a tyre size and load index to find the best alternative for your vehicle:
You have now 205/55 R16 91T tyres fitted and you plan to install narrower tyres (for the winter season, for example). The replacement tyres would be 16" tyres (195/60 89 H) then.
Unfortunately, the load rating of the selected tyres is lower than the load rating appropriate for your vehicle, so you cannot install the tyres.
A good alternative here would be a 15 inch tyre (195/65 R15) with a load index of 91T. In this case you need 15-inch wheels (the possibility of using such wheels).
When buying new tyres for your car, you want them to be safe, economic and comfortable. All these features are achievable provided that you know the tyre parameters - this is key when selecting tyres.
To check the parameters you may refer to the manual of your car which provides a detailed description of tyres recommended by the manufacturer. Such information can be easily found on the fuel filler flap, on the pillar behind the driver or on the inside of the driver's door.
Winter tyre tread.
What may happen when you use tyres with an improper load index?
Using tyres with a load index lower than that specified by the manufacturer is always dangerous. There are quite a few reasons why you should observe the manual guidelines.
Faster tyre wear - Tyres with the wrong load index may wear faster, increasing your car maintenance costs.
Risks when driving - Too much load on a tyre may result in the tyre blowout and a consequent accident on the road.
Loss of driving stability - You are likely to experience car handling issues and reduced comfort.
Rejected insurance claim - After a collision or any traffic incident, your car insurer may refuse to pay your claim if the car was fitted with tyres not recommended by the manufacturer.
No guarantee - When installing tyres with parameters non-compliant with specifications defined by the manufacturer, the tyre guarantee is void.
Possible fine - A police officer on a routine check may issue a fine if your tyres do not meet the manufacturer's requirements.
Modern safety systems installed in cars, such as traction control or ABS, are closely linked with the type of tyres recommended by the manufacturer. Fitting tyres that do not meet these requirements causes many problems and the risk of losing basic safety while driving.
Using higher load and speed indices
It is possible to mount tyres with higher load rating and speed rating than those provided by the manufacturer. However, is it worth using tyres with higher indices?
Remember that using tyres with a lower rating is dangerous and, as such, it is prohibited by law. Make sure that you and other road users are safe. Read the information necessary for selecting correct tyres.
Remember that using tyres with a lower rating is dangerous and, as such, prohibited by law. Always prioritise yours and other road users’ safety on the road. Read all the necessary information before selecting new tyres for your car or hitting the road with heavier load.