Your tyre size is printed on the sidewall, something like 205/55 R16 91V. Each part tells you a specific dimension or rating, and getting them right matters for safety, handling and the law. Here's how to decode it.
Breaking down 205/55 R16 91V
- 205 – tread width in millimetres.
- 55 – the profile or aspect ratio: sidewall height as a percentage of width (here 55% of 205mm).
- R – radial construction (almost all modern car tyres).
- 16 – wheel rim diameter in inches.
- 91 – the load index (maximum weight per tyre).
- V – the speed rating (maximum speed the tyre is rated for).
Where to find the right size
Read it off the existing tyre sidewall, or check the placard in the driver's door shut, inside the fuel filler flap, or in the handbook. The car's recommended size is the safe reference, especially if a previous owner fitted the wrong tyres.
Why you shouldn't mix sizes
Fitting a different width, profile or rim size changes the rolling diameter, which can upset the speedometer, ABS and stability systems, and may fail the MOT. Stick to the manufacturer's specification unless you've taken expert advice.
Not sure? We'll match it for you
Tell us your registration or read us the sidewall and we'll source the correct tyre. Our mobile fitting service brings the right size to your door across London and Birmingham. Book a fit.
