On this page
- What does 205/55 R16 91V mean?
- What do the load index and speed rating mean?
- How do you read the date of manufacture (DOT)?
- Where can you find the tyre size?
- What are the other markings on the sidewall?
- Why do we ask for the size when you request assistance?
- Need assistance in Milan?
- Frequently asked questions
What does 205/55 R16 91V mean?
Each part of the code describes a characteristic of the tyre.
| Part | Example | Meaning |
|---|---|---|
| Width | 205 | Section width of the tyre, in millimetres |
| Aspect ratio (profile) | 55 | Sidewall height as a percentage of the width (here 55% of 205 mm) |
| Construction | R | Radial construction, the most common on today's vehicles |
| Diameter | 16 | Diameter of the rim it fits, in inches |
| Load index | 91 | Code for the maximum load per tyre (91 = 615 kg) |
| Speed rating | V | Maximum permitted speed (V = 240 km/h) |
What do the load index and speed rating mean?
The load index is a conventional number corresponding to the maximum weight each tyre can carry; the speed rating is a letter indicating the maximum permitted speed. Some examples:
| Load index | Maximum load per tyre |
|---|---|
| 88 | 560 kg |
| 91 | 615 kg |
| 94 | 670 kg |
| 100 | 800 kg |
| Speed rating | Maximum speed |
|---|---|
| T | 190 km/h |
| H | 210 km/h |
| V | 240 km/h |
| W | 270 km/h |
| Y | 300 km/h |
The tyre fitted must have a load index and speed rating compatible with what's specified for your vehicle: the permitted combinations are listed in the vehicle registration document.
How do you read the date of manufacture (DOT)?
The date of manufacture is given by the last four digits of the DOT code printed on the sidewall: the first two are the week, the last two the year. For example 2423 means week 24 of 2023.
The full code may only appear on one side of the tyre: if you can't see it, look at the inner sidewall. Knowing the age of the tyre helps you judge whether it's worth repairing (see when can a tyre be repaired).
Where can you find the tyre size?
The size is first and foremost on the tyre sidewall, in raised lettering. There are other useful places too, especially if the tyre is dirty or hard to read:
- Vehicle registration document: lists the approved sizes for the vehicle.
- Label on the door pillar or inside the fuel filler flap: often shows recommended sizes and pressures.
- The vehicle's owner's handbook.
Note: some vehicles have different sizes on the front and rear axles. Check the wheel you're interested in.
What are the other markings on the sidewall?
Other markings describing specific characteristics may appear on the sidewall. The most common are:
- M+S: tyre suitable for mud and snow, according to the manufacturer.
- Mountain and snowflake symbol (3PMSF): tyre that has passed specific snow performance tests.
- XL or Reinforced: reinforced version, with a higher load index than the standard version of the same size.
- Run-flat markings (e.g. RFT, RSC, ZP, SSR): see run-flat tyres: how they work.
Why do we ask for the size when you request assistance?
We ask for the size because it lets us understand in advance what's needed for the job and tell you on the phone what's feasible, before we set off. The size, load index and speed rating identify the tyre precisely.
If you can't read it, a clear photo of the tyre sidewall is perfectly fine: you can send it with the assistance request or on WhatsApp. Any replacement with a new tyre is always checked on the phone depending on size and availability.
Need assistance in Milan?
With the size to hand, asking for help is easier. SOS Tyre operates 24/7, arriving in 30 minutes on average, in Milan and the surrounding province on cars, motorbikes, SUVs and vans, wherever the vehicle is: call +39 377 326 0999 or see our services.
Frequently asked questions
Can I fit a tyre with a lower speed rating?
In general the tyre must meet the minimum characteristics stated in the vehicle registration document. There are exceptions, for example for some winter tyres, governed by specific rules: before fitting a different rating, check the registration document and ask a tyre specialist.
Is the space-saver the same size as the other wheels?
No. A space-saver is generally a smaller size, different from the normal wheels, and is designed for temporary use only. Its size and maximum permitted speed are marked on the space-saver itself: stick to them until you refit a normal wheel.
What does the R in the size mean?
The R indicates the tyre's radial construction, i.e. the way the internal plies of the casing are arranged. It's the most common construction on modern cars. It doesn't indicate the rim diameter, which is the number straight after it, in inches.
How can I tell how old my tyre is?
Read the last four digits of the DOT code on the sidewall: the first two are the week, the last two the year of manufacture. For example 1022 means the tenth week of 2022. If you can't find the code, also look at the sidewall facing the inside of the vehicle.
Can the front and rear tyres be different sizes?
Yes, on some vehicles the front and rear axles have different sizes, often with wider rear tyres. In that case the wheels can't be swapped between axles. Always check the size of the wheel concerned and what's stated in the vehicle registration document.