Tyre size guide: how to find tire markings & interpret them


Posted by: Oluwaseun Solomon

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Can you identify the size of any car tyre? Well, if know you can't then this article is for you. Read about how to identify a car tyre size here now!

Are you a car owner or driver? 

If your answer is “Yes”, can you identify the size of your car tire? - No? Don't worry, in this article, Naijauto.com will educate you on how to do so. It’s definitely not rocket science, it is actually simpler than most people think.


There are different types of tires and identifying car tire sizes isn’t as difficult as it seems

1. Identifying car tire sizes - What are the things to look out for?

Below are the things you should look out for:

1.1. The Sidewall Markings

There are always some sidewall markings on car tires. If you look closely, you will see some sort of markings and codes, amongst these markings you will find the actual size of that tire.

Now, when you find these codes and markings which we claim has the tire size, how do you read or interpret them?

1.2. Tire sizes

 Tire sizes are mostly made up of different letters and numbers. Take, for example, you see a tire size writing as “186/60 R 14 82 H”. As you can clearly see that this marking comprises of letters and numbers. Now, let's analyze and explain what that information truly means for you when it comes to identifying the tire size:

  • 185 > this stands for the tire’s section width being stated in millimeters
  • 60 > this stands for the aspect ratio in percentage (i.e. the result from the division of the height of a tire’s sidewall by the actual tire’s width)
  • R > this denotes the construction type of the car tire – which in this case the “R” means its radial. There are indeed other construction types like you would guess
  • 14 > stands for the diameter of the rim stated in inches
  • 82 > stands for the Load index of the tire
  • H > stands for the speed rating of the tire

Guess what, that’s how to identify the size of any vehicle’s tire 😊.

Although, if you are looking into ordering for a new tire or new sets of tires then, we will recommend that you read further and learn some more important things to avoid ordering for the wrong tires.

>>> Some notes about spare tyres, check Spare tyres: How long do they last?


Read the sidewall markings and codes to identify a car tire size

2. Identifying car tire sizes - Other car tire size related information

Below we have provided some other useful information when it comes to identifying specific car tire sizes:

2.1.  Aspect Ratio

The Aspect ratio simply means the ratio of a tire’s width to the tire’s height. For example, a 60 series tire simply means that the tire’s height is equal to 60% of that tire’s width.

2.2. Speed Ratings

Every car tire actually carries a speed symbol. Yes, that’s right. The speed symbol is always written in the form of a letter and it simply indicates the maximum speed that is intended for such a car tire.

2.3. Load Indices

On the sidewall of a tire, you will also find the load-index being imprinted. This load index denotes the tire’s maximum load capacity when it is being driven at the maximum speed possible.

2.4. Tire Age

Each tire carries a 3-digit age code on its sidewall which indicates the month as well as the year of its manufacture. As an example, if you find the number 129 on a tire’s sidewall, it simply means the tire was manufactured in the 12th month of the year 1999 (December 1999).

>>> This car tyre is perfect for Nigerian roads: Michelin Tweel tyres: The future of car tyres

How To Read Tire Sizes and Specifications?

2.5. Other Markings

Some other markings you might see will look like:

  • M+S – this is identifying a mud and snow tires
  • DOT CODES – is coding that satisfies the US Department of Transportation. The code mostly contains numbers and letters e.g. DOT DVDE MTA 129
  • E Marks – In accordance with the ECE Reg 30 in the European community, tires for sale must each carry an Emark e.g. you could see it written like; E4 027550

2.6. Air Pressure

A tires main function is to carry the vehicle’s load. Therefore, it is crucial to maintaining the correct air pressure for tires to be used. Over-inflation of a car tire will cause irregular and rapid wear to such tire. Under-inflation can lead to possible car accidents as it damages the tire structure.

When improper air pressure is maintained in a tire, it affects such tire by not allowing it to function the way it had been designed to. In order to get the best performance out of a car tire, the recommended air pressure by the vehicle and/or tire manufacturer should be maintained.

2.7. Wheel Balancing and Alignment

Improper wheel balancing and alignment is always the major cause of rapid tread wear in tires. When symptoms like harshness, vibration, and abnormal noise of steering wheel is seen or felt, they are close indicators of improper balancing and alignment. When such is observed, appropriate check and corrections should be made on time to avoid damaging the car tires.

>>> Naijauto offers the best guides for Naija car owners & drivers:

3. Other Quick tips:

  • Always use suitable tires in the appropriate vehicle. Avoid using too small or too big tires that don’t fit
  • Don’t fit wrong tires to wrong wheels. E.g. fitting radial-ply tires to the axles with cross-ply tires initially and vice versa
  • Avoid cuts that are more than 10% of the car tire’s section width or cuts more than 25mm in length. Generally, just avoid tires with a deep cut or break in its fabric
  • Make sure that no portion of the cord or ply structure is exposed to the open. As well, avoid tires with a tear, bulge or lumps which might have been caused by partial fracture or separation of the tire structure

4. Conclusion

With all of our above-provided information, you should be able to roughly identify the car tire sizes now and be equipped with enough idea on how to make the correct order for your next replacement tires as the case might be.

But, if at any point you still get confused, you can always come back to this post on our site here at Naijauto to confirm any confusing thing or you might just go to a trusted tire expert to help you out.

>>> If you found this post helpful, you should check out our other useful car maintenance tips and advice.

Oluwaseun Solomon

Oluwaseun Solomon

Market news

Oluwaseun Solomon is a prolific and diligent automobile writer at Naijauto.com. He's also an experienced digital marketer and a creative multimedia developer that specializes in video editing. He currently contributes informative and easy to read articles on topics covering transportation, traffic updates, auto industry updates, and different car reviews.
When Solomon is not writing, you will either find him composing music, editing videos or simply enjoying YouTube "TEDx Talk" videos with a chilled drink :)

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