Tire Speed and Load Indices: The Complete 2025 Guide for a High-Performance and Safe Fleet

Your tire speed and load ratings are not optional: they are essential to the performance of your fleet. The wrong choice can lead to premature wear, excessive fuel consumption, and increased accident risk.

Learn how to master them: protect your drivers, optimize your budget, and ensure your fleet's compliance. With this guide, discover how to decipher these ratings to make them your allies, guarantee safer journeys, and get a head start on your goals.

What is a tire's speed rating?

The speed rating of a tire, represented by a letter on its sidewall, is a code that indicates the maximum speed at which that tire can safely travel while carrying its maximum load. This is not a recommendation for driving speed, but rather a limit on the structural capacity of the tire. Exceeding this maximum speed can cause overheating, deformation, and potentially a blowout, with dramatic consequences. The speed rating is therefore a non-negotiable safety criterion.

How can I find the speed rating on my tire?

The speed rating is the last letter of the main marking on the sidewall of the tire. It follows directly after the load rating.

Marking example: 205/55 R16 91V

• 205: Tire width in mm.
• 55: Sidewall height (as a percentage of width).
• R: Radial structure.
• 16: Rim diameter in inches.
• 91: Load index.
• V: Speed rating.

Table of speed ratings and corresponding maximum speeds

This table helps you decode the speed rating of your tires. Each letter corresponds to a maximum speed in km/h.

What is a tire load index?

The load index is a numerical code that indicates the maximum weight (maximum load) that a single tire can carry at its optimum inflation pressure and maximum speed. To find out the total load your vehicle can carry, multiply the axle load (i.e., by two or four tires). Compliance with this load index is essential for vehicle stability and to prevent structural failure.

How can I find the load index on my tire?

The load index is the number located just before the speed rating on the sidewall of the tire.

Marking example: 205/55 R16 91V

• 91: This is the load index.
• V: Speed index.

Table of load indices and corresponding maximum loads

This load index table allows you to convert the numerical code into the weight capacity in kg.

Example: a load index of 91 means that the tire can carry a load of 615 kg.

 

XL tires: what does that mean?

The “XL” (Extra Load) or “RF” (Reinforced) marking means that the tire has a reinforced casing. It is capable of carrying a higher load and pressure than a standard tire of the same size. Choosing an XL tire is often necessary for heavy vehicles such as SUVs, minivans, or utility vehicles in order to achieve the load index required by the manufacturer.

 

Choosing the right indices: tips and recommendations

How do I choose the right speed rating for my vehicle?

The golden rule is simple: choose a speed rating equal to or higher than that of the tires originally fitted by the manufacturer. This information is the absolute reference.

How do I choose the right load index for my vehicle?

Similarly, you must choose a load index equal to or higher than that of the original tires. It is strictly prohibited to fit a lower load index.

Can I fit tires with a higher load or speed rating?

Yes. Fitting tires with a higher load index or speed rating is permitted and often safe. A higher load index can even offer better durability. A higher speed rating can sometimes result in a tire with a stiffer rubber compound, which may slightly impact comfort. The important thing is to never go below the recommended specifications.

Can I fit tires with a lower load or speed rating?

• Lower load index: This is strictly prohibited and extremely dangerous. The tire is not designed to support the weight of the vehicle, which drastically increases the risk of blowouts, especially when fully loaded or at high speeds.
• Lower speed rating: It is also prohibited to fit a speed rating lower than the original for summer tires. There is a real risk of tire failure at high speeds. The only exception is for winter tires.

Speed and load indices for winter tires: specific advice

Regulations allow winter tires (marked M+S and/or 3PMSF) to have a lower speed rating than the original summer tires (for example, changing from V to T). In this case, a label must be affixed inside the vehicle, visible to the driver, indicating the new maximum speed not to be exceeded. The load index must always remain the same or higher.

Changing tire size: impact on speed and load ratings

If you change the dimensions of your tires (for example, for tuning purposes), you must ensure that the new tires have a load index and speed rating that are at least equivalent to those of the original tires.

 

Legislation and compliance: comply with the indices recommended by the manufacturer

In the event of a technical inspection or inspection by law enforcement, non-compliant indicators may result in a re-inspection, a fine, or even immobilization of the vehicle. In the event of an accident, the insurance company may refuse to cover the damage if it can prove that non-compliant tires were involved.

Where can I find this information?

1. On the sidewall of the tire: This is the most straightforward place to read the current markings.
2. In the vehicle manual: The manufacturer details the approved tire sizes here.
3. On the tire pressure label: Located in the driver's door frame, fuel filler flap, or glove compartment, it often contains all the information on recommended sizes and ratings.
4. On the car manufacturer's website: The support or technical sections may provide this data.

 

Simplify tire maintenance with Dadycar

Beyond choosing the right tires, managing tire replacement logistics for an entire fleet is a real challenge. How can you ensure that seasonal or wear-related tire changes are carried out on time for each vehicle without it becoming an administrative headache?

This is where a fleet management tool like Dadycar provides a targeted and effective solution. The platform simplifies this crucial process with two key features:

• Automated Reminders: Never miss a deadline again. You can schedule automatic reminders for seasonal tire changes (summer/winter) or based on each vehicle's mileage. This ensures you are notified at the right time to schedule the service.
• Simplified Service Booking: Once you receive the alert, the platform allows you to schedule and book tire changes directly with your partners or garages. No more multiple phone calls and tedious coordination.

By transforming tire change management into a simple, automated process, you save valuable time and ensure that your fleet remains compliant and safe at all times, ready to hit the road.