Every tyre has a series of numbers and letters moulded into the sidewall that describe its dimensions and performance ratings. Understanding these markings means you can confidently verify that a replacement tyre is correct for your vehicle.
A typical tyre marking looks like this: 205/55 R16 91V. Each part of this code tells you something specific about the tyre.
Width, Profile and Rim Diameter
The first number — 205 in the example — is the tyre width in millimetres, measured from sidewall to sidewall. The second number — 55 — is the aspect ratio, representing the height of the sidewall as a percentage of the width.
The letter R indicates radial construction (standard for all modern car tyres). The following number — 16 — is the rim diameter in inches. This must match your wheel exactly.
Load Index and Speed Rating
The number after the rim size — 91 in the example — is the load index, indicating the maximum weight the tyre can support. The letter V is the speed rating, indicating the maximum sustained speed the tyre is designed for (V = 149mph).
Always replace tyres with a load index and speed rating equal to or higher than the original fitment. Fitting lower-rated tyres is unsafe and may invalidate your vehicle insurance.
Finding the Right Tyre Size for Your Car
Your tyre size is found on the sidewall of your existing tyres, in your owner's handbook, and sometimes on a sticker inside the driver's door jamb or fuel filler cap.
When you contact Glasgow Mobile Tyre Fitters, simply quote the full size marking and we will confirm availability and pricing. We carry a wide stock of popular sizes and can source less common sizes quickly.
Glasgow Mobile Tyre Fitters provide fast, professional mobile tyre fitting across all Glasgow postcodes. Call us or book online — same-day service available.