How to Identify the Exact Tyre Size and Match for Your Car

Buying a car tyre isn't simply about finding one that can fit your wheel.

Your vehicle was designed to use tyres with specific dimensions, load capacity and speed ratings. Choosing the wrong tyre can affect handling, ride comfort, fuel consumption, braking and even the accuracy of your speedometer.

Unfortunately, many car owners in Nigeria only discover this when it's time to replace their tyres.

You may hear:

"This one will fit."

"It's almost the same size."

"We've been putting this size on Camry."

But a tyre fitting on your rim doesn't necessarily mean it's the correct tyre for your car.

So how do you identify the exact match?

Here's what every car owner should know.

1. Start With the Numbers on Your Current Tyre

Look at the sidewall of your tyre.

You'll find several numbers and letters printed on it. One of the most important will look something like:

225/65 R17 102H

This code tells you a lot about the tyre.

Let's break it down.

225 – Tyre Width

The first number represents the width of the tyre in millimetres.

In our example:

225 = 225mm wide

A tyre marked 235/65 R17 would therefore be wider than a 225/65 R17 tyre.

Don't assume that going wider automatically means better performance. Your vehicle and wheel need to be suitable for the tyre.

2. Understand the Aspect Ratio

The second number is the tyre's aspect ratio.

For:

225/65 R17

The 65 means the sidewall height is 65% of the tyre's width.

It does NOT mean the sidewall is 65mm high.

This number matters because changing the aspect ratio changes the overall diameter of the tyre.

That can affect ride height, comfort, handling and speedometer readings.

3. What Does the "R" Mean?

The R in:

225/65 R17

means Radial.

Most modern passenger vehicles use radial tyres.

It describes the construction of the tyre rather than its size.

4. The Final Number Is Your Rim Size

The 17 means the tyre is designed for a 17-inch wheel.

This is one specification you cannot casually change.

A tyre designed for a 17-inch wheel cannot simply be installed on an 18-inch wheel.

So:

225/65 R17

and

225/60 R18

are completely different tyre specifications, even though the width is the same.

5. Don't Ignore the Load Index

Now look at the complete example:

225/65 R17 102H

The 102 is the load index.

It represents the maximum load the tyre is designed to support at its rated conditions.

This becomes particularly important for heavier vehicles such as SUVs, crossovers and pickups.

You shouldn't replace a tyre with another one that has an inadequate load rating simply because the physical dimensions match.

6. Check the Speed Rating

The final letter — H in our example — is the tyre's speed rating.

Different tyres may carry ratings such as:

S, T, H, V, W or Y

The rating indicates the tyre's tested maximum speed capability under specified conditions.

For normal replacement, motorists should follow the vehicle manufacturer's tyre specifications rather than choosing a lower rating simply because the tyre is cheaper.

7. Check the Driver's Door Sticker

Here's something many Nigerian drivers don't check.

Open the driver's door and look around the:

door jamb, door pillar or inside edge of the door.

Many vehicles have a manufacturer's information sticker showing the recommended tyre specifications.

Depending on the vehicle, it may show:

• Front tyre size

• Rear tyre size

• Recommended tyre pressure

• Wheel information

This can be more reliable than simply copying whatever tyres are currently on a used car.

Why?

Because a previous owner may already have installed a different tyre or wheel size.

8. Check Your Owner's Manual

Your vehicle owner's manual is another useful source.

Look for sections covering:

Tyres, wheels, specifications or tyre pressure.

The manufacturer may specify more than one approved tyre size depending on the vehicle's trim and wheel option.

For example, two versions of the same Toyota, Lexus or Mercedes-Benz model may leave the factory with different wheel sizes.

That's why searching by the vehicle name alone isn't always enough.

9. Your Car's Model Year Matters

This is one of the biggest mistakes people make when buying tyres.

Imagine two people both drive a Toyota Camry.

One owns a 2010 Toyota Camry.

The other owns a 2022 Toyota Camry.

You shouldn't assume their tyre requirements are identical simply because both vehicles are Camrys.

Manufacturers change wheel and tyre specifications across different generations, trims and model years.

The same applies to vehicles such as the:

Toyota Corolla
Toyota Highlander
Lexus RX 350
Lexus ES 350
Honda Accord
Mercedes-Benz C-Class
Hyundai Tucson
Kia Sportage

This is why your make + model + year is important when searching for the right tyre.

10. Trim Level Can Also Change the Tyre Size

Even the model year isn't always enough.

Higher trims sometimes come with larger wheels.

For example, the standard version of a vehicle might have 17-inch wheels while another trim of the same vehicle and year could have 18-inch or 19-inch wheels.

That means this search:

2021 Toyota Camry tyre size

may still produce several possible sizes.

You need to confirm which wheel package is actually installed on your particular vehicle.

11. Front and Rear Tyres May Be Different

Don't automatically assume all four tyres use the same size.

Some vehicles use what is known as a staggered tyre setup.

This means the rear tyres may be wider than the front tyres.

You may see something like:

Front: 225/45 R18

Rear: 255/40 R18

This arrangement is more common on certain performance and luxury vehicles.

If your vehicle was designed this way, ordering four tyres based only on the size of one front tyre could result in buying the wrong set.

Always check both axles.

12. Don't Forget the Tyre Production Date

Correct size doesn't automatically mean a tyre is a good purchase.

You should also check when it was manufactured.

Look around the tyre sidewall for the DOT marking. The final four digits of the relevant date code identify the production week and year.

For example:

2425

means the tyre was manufactured during the 24th week of 2025.

This is particularly important when buying tyres that may have spent a long time in storage or when considering used tyres.

13. Be Careful When Buying Tokunbo Tyres

Tokunbo tyres remain common in Nigeria because they're generally cheaper than equivalent brand-new tyres.

But matching the size is only the beginning.

A used tyre should also be inspected for:

• Sidewall cracks

• Bulges

• Cuts

• Uneven tread wear

• Previous repairs

• Damaged beads

• Tread condition

• Manufacturing date

A tyre can still have visible tread and be in poor overall condition.

Don't judge a tyre by tread depth alone.

14. Don't Buy a Tyre Just Because "It Fits"

This is perhaps the most important lesson.

Suppose your vehicle uses:

225/65 R17

A seller may have:

235/65 R17

and tell you:

"It will enter."

Physically fitting the wheel doesn't automatically make it the correct replacement.

Changing tyre dimensions can alter overall diameter, clearance, steering response and other characteristics.

Before changing from the manufacturer's recommended size, confirm that the alternative is appropriate for your particular vehicle.

The Easiest Way to Find Your Car's Tyre Match

You don't necessarily need to memorise all these numbers.

This is one of the reasons CarTyres.ng was created.

Instead of guessing which tyre fits your vehicle, you can start with your vehicle information and find relevant tyre specifications.

Enter details such as your:

Car Make → Model → Year

and use CarTyres.ng to identify tyre information for your vehicle.

Already know your tyre size?

You can also search using the specification printed on your tyre, such as:

205/55 R16

215/60 R17

225/65 R17

235/55 R18

This makes it easier to move from "I need new tyres" to knowing exactly what specification you should be looking for.

Before You Buy Your Next Tyre

Take two minutes and check your car.

Look at the tyre sidewall.

Check the driver's door sticker.

Confirm the model year.

Check whether the front and rear tyre sizes are identical.

Then compare that information with the manufacturer's recommended specifications.

Those few checks could prevent you from spending money on tyres that aren't the correct match for your vehicle.

For Nigerian motorists who want a simpler way to research vehicle tyre specifications, sizes and available options, visit CarTyres.ng.

Don't just buy a tyre because it fits. Find the tyre that matches your car.