Tire speed and load indices

Tire speed and load indices: the complete guide to a high-performing, safe fleet

Your tires' speed and load indices are not optional: they are essential to your fleet's performance. The wrong choice can lead to premature wear, higher fuel consumption and a greater risk of accidents.

Learn to master them: protect your drivers, optimize your budget and keep your fleet compliant. This guide shows you how to read these indices so they work for you, make every trip safer and get ahead on your goals.

What is a tire's speed index?

A tire's speed index, often called its speed rating, is the letter on its sidewall that shows the maximum speed at which the tire can safely run while carrying its maximum load. It is not a recommended driving speed but a limit on the tire's structural capacity. Going beyond this maximum speed can cause overheating, deformation and potentially a blowout, with dramatic consequences. The speed index is therefore a non-negotiable safety criterion.

How do I find the speed index on my tire?

The speed index is the last letter of the main marking on the tire's sidewall. It comes right after the load index.

Example marking: 205/55 R16 91V

• 205: tire width in mm.

• 55: sidewall height (as a % of the width).

• R: radial construction.

• 16: rim diameter in inches.

• 91: load index.

• V: speed index.

Speed index table and matching maximum speeds

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

Speed index	Maximum speed (km/h)	Typical vehicle use
Q	160 km/h	Light commercial vehicles, winter tires
R	170 km/h	Commercial vehicles, winter tires
S	180 km/h	City cars, family cars
T	190 km/h	Compact sedans, minivans
H	210 km/h	Touring sedans, SUVs
V	240 km/h	Powerful sedans, sports cars
W	270 km/h	High-performance sports cars
Y	300 km/h	Supercars, exceptional vehicles
ZR (Y)	> 300 km/h	Hypercars ("ZR" alone means over 240 km/h)

What is a tire's load index?

The load index is a numerical code that shows the maximum weight (maximum load) a single tire can carry at its optimal inflation pressure and maximum speed. To find the load an axle or the whole vehicle can carry, multiply this load by the number of tires involved: two for an axle, four for a car. Respecting the load index is fundamental to vehicle stability and to avoiding structural failures.

How do I find the load index on my tire?

The load index is the number just before the speed index on the tire's sidewall.

Example marking: 205/55 R16 91V

• 91: this is the load index.

• V: speed index.

Load index table and matching maximum loads

This load index table lets you convert the numerical code into the weight the tire can carry, in kg.

Load index	Maximum load (kg)	Load index	Maximum load (kg)
85	515 kg	95	690 kg
86	530 kg	96	710 kg
87	545 kg	97	730 kg
88	560 kg	98	750 kg
89	580 kg	99	775 kg
90	600 kg	100	800 kg
91	615 kg	101	825 kg
92	630 kg	102	850 kg
93	650 kg	103	875 kg
94	670 kg	104	900 kg

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

XL tires: what does that mean?

The "XL" (Extra Load) or "RF" (Reinforced) marking means the tire has a reinforced casing. It can carry a higher load and pressure than a standard tire of the same size. An XL tire is often needed on heavy vehicles such as SUVs, minivans and commercial vehicles to reach the load index required by the manufacturer.

Choosing the right indices: tips and recommendations

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

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

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

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

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

Yes. Fitting tires with a higher load index or speed index is allowed and often safe. A higher load index can even mean a longer tire life. A higher speed index can sometimes mean a stiffer rubber compound, which slightly affects comfort. What matters is never going below the recommended specifications.

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

• Lower load index: this is strictly prohibited and extremely dangerous. The tire is not designed to carry the vehicle's weight, which drastically increases the risk of a blowout, especially when fully loaded or at high speed.

• Lower speed index: fitting summer tires with a lower speed index than the original is also prohibited. The risk of tire failure at high speed is real. The only exception is winter tires.

Speed and load indices for winter tires: specific advice

The regulations allow winter tires (marked M+S and/or 3PMSF) to have a lower speed index than the original summer tires (for example, going from V to T). In that case, a label must be placed inside the vehicle, where the driver can see it, stating the new maximum speed not to be exceeded. The load index, however, must always stay the same or higher. For the winter equipment requirement under France's Mountain Law (loi Montagne), only tires bearing the alpine symbol (3PMSF) have been accepted since 1 November 2024; with tires marked only M+S, you must carry snow chains.

Changing tire size: impact on speed and load indices

If you change the size of your tires (for tuning, for example), you must make sure the new tires have a load index and a speed index at least equivalent to those of the original fitment.

Legislation and compliance: stick to the indices recommended by the manufacturer

During a roadworthiness test or a police check, non-compliant indices can lead to a re-test, a fine or even immobilization of the vehicle. After an accident, the insurer can refuse to cover the damage if it proves the non-compliant tires were involved.

Where can I find this information?

1. On the tire sidewall: the most direct place to read the current markings.

2. In the vehicle manual: the manufacturer lists the approved tire fitments there.

3. On the tire pressure label: found on the driver's door frame, the fuel filler flap or the glove box, it often gives all the information on recommended sizes and indices.

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 indices, organizing tire replacements for a whole fleet is a real challenge. How do you make sure seasonal or wear-related tire changes are done on time for every vehicle, without it becoming an administrative headache?

This is where a fleet management tool like Dadycar provides a targeted, 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, so you are notified at the right time to plan the work.

• Simplified service booking: once you receive the alert, the platform lets you schedule and book the tire change directly with your partners or garages. No more endless phone calls and tedious coordination.

By turning tire change management into a simple, automated process, you save valuable time and make sure your fleet stays compliant and safe at all times, ready for the road.