What Tyres Are on My Car? How to Check, Choose and Replace

Understanding what tyres are right for your car is the difference between a confident, safe drive and a stressful one. Many drivers never give their tyres a second thought until a warning light blinks or a flat stops them in their tracks. 

This guide demystifies tyre sizes and recommends the best way to check and choose the right rubber for your car. We’ll also show you how Martins Tyres can save you time with expert advice and mobile fitting. 

Why Knowing What Size Your Tyres Are Matters

Tyres are your only contact with the road. The wrong size or type can alter your speedometer readings, compromise handling, and even damage suspension components. Drivers who choose tyres that are too small or too large may also void their insurance or fail their MOT. 

The good news is that checking what your tyre size is can be a simple task once you know where to look and what the numbers mean.

Where to Find Your Tyre Size

Most vehicles display tyre information in three places:

• Owner’s manual: This lists the manufacturer’s recommended tyre dimensions and pressures.

• Door-jamb or glovebox sticker: Many cars have a pressure or size chart on the driver’s door pillar or inside the glovebox. It will display both front and rear tyre sizes and recommended pressures, whether loaded or unloaded.

• Existing tyre sidewall: you can read the code on your current tyres to double-check the size.

If you are unsure or the stickers are missing, you can also find the tyre size using your registration number on many retailer websites. But reading your tyre’s sidewall is the quickest DIY method.

Decoding the Tyre Sidewall Code

Every tyre is marked with a series of numbers and letters. A typical code might read 205/55 R16 91V. Here’s what each part means:

Look closely, and you’ll also see a DOT code indicating what week and year your car tyres were manufactured (e.g., 4222 means week 42 of 2022). Tyres should generally be replaced after six years, regardless of tread depth, as rubber hardens and loses grip.

Why Matching Tyre Sizes is Important

Fitting different-sized tyres on the same axle can affect steering geometry and braking balance. Experts recommend fitting identical tyres on all four corners or following the manufacturer’s staggered set-up for performance vehicles. Mixing widths, load ratings or speed ratings may also invalidate your insurance and compromise stability.

When to Replace Your Tyres

Even if you have the correct size, tyres wear out. You should replace them when:

• Tread depth is below 1.6 mm: Driving on bald tyres is illegal and dangerous. Many tyre shops suggest replacing at 2 mm for added safety.

• Uneven wear or damage: Cuts, bulges, cracks or punctures that can’t be repaired require immediate replacement.

• Age: Rubber degrades over time. If a tyre is more than five or six years old, consider replacing it even if it looks fine. 

Maintaining proper pressure, rotating tyres, and ensuring wheel alignment will extend tyre life.

Tips on Choosing the Right Tyres for Your Driving

Not all tyres are created equal. After confirming what your car’s tyre size is, think about how and where you drive. Here are some factors to consider:

• Season: Summer tyres excel in warm, dry or wet conditions, while winter tyres use softer rubber and deeper tread for cold, icy roads. All-season tyres provide a compromise for drivers who want year-round convenience.

• Driving style: Performance tyres feature stiffer sidewalls and grippier compounds for responsive handling. Touring tyres prioritise comfort and longevity.

• Weather resistance: Some tyres evacuate water better, reducing aquaplaning risk. Others are designed for low rolling resistance to save fuel or to reduce noise.

• Budget vs. premium: Premium tyres often last longer and offer superior grip. Budget or mid-range tyres save money upfront but may wear out sooner and perform less consistently.

Here are the recommended tyre types for your car

Note: Always ensure the load and speed ratings meet your vehicle’s requirements. For specialist vehicles such as 4x4s, vans, or electric cars, select tyres specifically designed for those applications.

Can I Put a Different Size Tyre on My Car?

Some sports cars use wider rear tyres than fronts, but this is carefully engineered and tested. If you change tyre size or wheel diameter, you must also adjust the rim size. Doing so affects steering, suspension and speedometer calibration and should only be done with professional guidance.

Generally, it’s safer and simpler to stick with the sizes specified by your manufacturer and fitted when the car was new. That way you maintain the balance and handling the engineers intended.

How Martins Tyres Can Help

Checking and choosing the right tyres doesn’t have to be a solo mission. At Martins Tyres, we offer:

• Free tyre checks: Our technicians can inspect tread depth, pressure and overall condition and confirm your tyre size. No appointment necessary.

• Wide range of brands: We stock leading brands such as Michelin, Continental, Bridgestone, Pirelli and more. Whether you need budget tyres for a commuter car or premium performance tyres, we have them.

• Mobile fitting and repair: Can’t get to the garage? We come to you. Our mobile fitting vans cover Bracknell, Windsor, Egham, Guildford and surrounding areas. We’ll remove your old tyres, fit and balance the new ones, recalibrate tyre-pressure monitoring systems and take away the waste for recycling.

• Same-day service: Need tyres urgently? We often offer same-day appointments. Just call our team or book online.

• Transparent pricing: What we quote is what you pay – no hidden extras. We’ll talk you through your options and recommend tyres that suit your driving style and budge