How to Read Tyre Sizes

Choosing the right tyre size is important for safety, handling, fuel economy, and MOT compliance.
This guide explains exactly how to read tyre sizes like 205/55R16 91V and what each number means.

Example Tyre Size: 205/55R16 91V

A common tyre size looks like this:

205/55R16 91V

Each part has a meaning:

✅ 205 = Tyre Width (mm)

This is the width of the tyre in millimetres, measured from sidewall to sidewall.

So 205 means the tyre is 205mm wide.

✅ 55 = Profile / Aspect Ratio (%)

This is the tyre sidewall height as a percentage of the width.

So 55 means the sidewall height is 55% of 205mm.

205 × 55% = 112.75mm sidewall height

✅ R = Construction Type

Most modern tyres are Radial, shown as:

R = Radial construction

(Almost all car tyres in the UK are radial.)

✅ 16 = Wheel / Rim Size (inches)

This is the diameter of the wheel the tyre fits, measured in inches.

So R16 means the tyre fits a 16 inch alloy/steel wheel.

✅ 91 = Load Index

This number tells you how much weight each tyre can safely carry.

91 = 615kg per tyre (maximum load)

⚠️ Always match or exceed the load index recommended for your vehicle.

✅ V = Speed Rating

This letter tells you the maximum speed the tyre is designed for.

Common speed ratings:

  • T = 118 mph

  • H = 130 mph

  • V = 149 mph

  • W = 168 mph

  • Y = 186 mph

⚠️ Always match or exceed your vehicle’s required speed rating.

What Does XL Mean on a Tyre?

You may see XL after the speed rating, like:

205/55R16 91V XL

✅ XL = Extra Load
This means the tyre has a stronger construction and can carry more weight at higher pressures.

It’s common on:

  • larger wheels (18” / 19” / 20”)

  • performance tyres

  • heavier vehicles

What Does “Runflat / RFT” Mean?

Some tyres may say:

RFT / Runflat

✅ These tyres are designed to drive a short distance after a puncture (only on vehicles that support runflats).

⚠️ Don’t fit runflats unless your vehicle is designed for them.

Where Can I Find My Tyre Size?

You can find your tyre size in 3 places:

✅ 1) On the tyre sidewall

Look for something like:
205/55R16

✅ 2) Inside the driver’s door area

Many vehicles have a sticker showing:

  • tyre sizes

  • pressures

  • load/speed ratings

✅ 3) Your vehicle handbook

This will confirm the approved sizes.

Can I Fit a Different Tyre Size?

Sometimes vehicles have multiple approved tyre sizes (for example different wheel trims).

However, fitting the wrong size can cause:
❌ rubbing on arches
❌ incorrect speedometer reading
❌ poor handling / braking
❌ MOT issues
❌ insurance issues

If you’re unsure, message us and we’ll help.

Quick Tyre Size FAQ

Is 205/55R16 the same as 205/55/16?

Yes ✅
They mean the same tyre size.

What’s the difference between 205/55R16 and 215/55R16?

The tyre is wider (215 vs 205).
This can affect clearance, handling, and speedometer accuracy.

Do I need to replace tyres in pairs?

For best safety, yes ✅
Replacing tyres in pairs (especially on the same axle) helps stability and grip.

Shop Tyres by Size

If you already know your size, you can shop our tyres online:

✅ Car Tyres
✅ Van Tyres
✅ 4×4 / SUV Tyres
✅ Summer / Winter / All-Season Tyres

📩 If you need help choosing the right tyre, contact us and we’ll point you to the correct size and rating.

✅ Optional (Add this at the bottom for internal linking)

Links (edit these if your collection handles differ):

  • /collections/car-tyres

  • /collections/van-tyres

  • /collections/4x4-tyres