Tyre size guide
How to find your tyre size in under a minute.
Every car tyre has its size moulded into the sidewall. Once you can read it, you can get an accurate mobile fitting quote without a registration lookup or a trip to a garage.
What the numbers mean
205/55 R16, broken down
Using the most common UK car tyre size as the example.
- 205Width
- The width of the tyre in millimetres, measured across the tread from sidewall to sidewall. Common car widths run from 155 to 325.
- 55Profile (aspect ratio)
- The height of the sidewall as a percentage of the width. A 55 profile means the sidewall is 55% of 205 mm. Lower numbers mean a shallower, sportier sidewall.
- RConstruction
- R stands for radial, which is how almost every modern car tyre is built. You can ignore this letter when entering your size.
- 16Rim diameter
- The diameter of the wheel the tyre fits, in inches. Most cars sit between 14 and 20 inches.
Three checks before you order
- 1. Read the right tyre. Front and rear tyres can be different sizes. Read the one that needs replacing.
- 2. Note the load and speed rating. The code after the size, such as 91V, matters for insurance and safety. Send it with your WhatsApp message if you can.
- 3. Check the other tyre on the same axle. Tyres on the same axle should match in size and ideally in pattern. If both are worn, replacing the pair is usually the better choice.
Got the numbers? Enter them on the home page quote journey, share your location and we will reply on WhatsApp. If the tyre is flat now, see emergency tyre fitting in London.
Questions
Tyre size FAQs
Where is the tyre size written?
On the outer sidewall of every tyre, moulded into the rubber. Look for the pattern width/profile R rim, for example 205/55 R16. It is usually near the brand name and can be easier to read by crouching down and using your phone torch.
What do the letters and numbers after the size mean?
After the size you will usually see a load index and a speed rating, for example 91V. 91 is the maximum load per tyre and V is the top speed the tyre is rated for. Your replacement should match or exceed both; we check this for you when we quote.
Are my front and rear tyres the same size?
On most cars, yes. Some performance and rear-wheel-drive cars use wider rear tyres, so always read the tyre you actually want replaced rather than assuming.
Can I find my tyre size from my registration number?
Registration lookups often return several possible sizes because manufacturers fit different wheels to different trims. The sidewall is the only way to be certain, which is why our quote journey asks for the three numbers directly.
What if the size on my tyre is not in your list?
Message us on WhatsApp with a photo of the sidewall. Unusual sizes, van tyres and run-flats can still be supplied; they just need a quick check before we quote.
Nothing to pay until you confirm
Found your size?
Enter the three numbers, share your location and open WhatsApp with the message ready.