The Ultimate Tyre Guide

Contents

Why are Tyres so Important?

Do I Need New Tyres?

Tyre Repairs

Tyre Age

Tyre Damage

How to Diagnose Your Tyres

20p Tyre Tread Check

Different Tyres On The Same Axel

Illegal Tyres and Tyre Insurance

What Tyres Do I Need?

What Does 'OE' Mean?

All Weather Tyres

How Much Do Tyres Cost?

How Are Tyres Labelled?

Tyre Brands

Tyre Sizes

Replacing Tyres in Pairs

What Are Run Flat Tyres?

Why are Tyres So Important? 

You might not realise, but your tyres are by far one of the most important parts of your vehicle. Today we want to share everything you need to know about car tyres in our ultimate tyre guide. We'll cover the basics, diagnosing problems, different types of tyres, even how tyres are made! We want to show you how much thought, technology and engineering goes into each wheel. Let's roll!

Here are the main functions of a car tyre: -

Weight Bearing

How much does the chassis of your car weigh? Chances are it is around a tonne or so. There's no getting away from the fact that at the very bottom of all that weight are four contact points supported by your tyres.

They Allow the Vehicle to Accelerate, Brake and Absorb Bumps

This is a fact that has existed since the invention of the wheel. Because the tyres are in constant contact with the road, they are the only means of propelling the car forward using the accelerator, bringing the car to a stop using the brakes...

And…

Along with the suspension, they are responsible for ensuring that you don't feel every bump in the road.

They Enable you to Change Direction

Whether you have rear-wheel drive or front-wheel drive, the front two tyres dictate the direction in which the car will travel when you turn the steering wheel.

Your Tyres Dictate the 'Quality' of Your Drive

Not all tyres are created equal. Some do a good job of keeping you comfortable. Others can ensure that you arrive at your destination tired (pun intended) and worn out. You'll also find that some tyres are noisier than others.

Do I Need New Tyres?

If you are asking the question, then there is a strong possibility that you might.

There are several reasons to consider replacing your tyres. These include: -

• Punctures
• Age
• Damage
• Abnormal Wear
• Normal Wear and Tear

Let's take a look at the above in more detail.

Repairing your Tyres

Here's the truth.

If you've got a puncture, some tyres can be repaired, and some can't. Let's look at the key differences: -

Tyre Repairs | Temporary Fixes

Sealant - Often, you'll find that your vehicle comes with a small can of sealant. This is designed to be a temporary fix to get you to a garage or safety.

Self-Sealing Tyres – This tyre technology works similarly to the above, except it is automatic. The sealant is held within the tyre and is released when the internal pressure drops below a minimum value.

Run-Flat Tyres – These are tyres with a really rigid sidewall. They are strong enough to allow you to continue to drive, even with a puncture.

When Can you NOT Repair a Tyre

If you perform a check on your tyre and see any of the following, then you will legally be obliged to find a replacement: -

More than one puncture – Often, multiple punctures mean that the tyre isn't salvageable.

Aged Tyres, or those showing signs of degradation – You'll find any reputable dealer will refuse to repair an old tyre. If the age can't be verified, any tyre with cracks or signs of age in the rubber will also require a replacement.

Exposed chord or bead damage – The chord of a tyre is a fabric that runs through the tyre, giving it structural integrity. If this is exposed or damaged, then you'll have to replace it. The 'bead' is the area around the tyre that connects it to your alloys. If a good seal can't be made, the tyre can't be inflated.

Shallow Tread – The minimum tread required on any car tyre in the UK is 1.6mm. Below that, and you are driving illegally. Most manufacturers recommend considering a replacement when the tread gets below 3mm.

Tyre Damage | What You NEED to Know

Sometimes your tyres can be inflated but still need replacingif they are damaged.

Driving around on damaged tyres is never a good idea.  Damage to your car tyres can take many different forms. The reasons are varied, but generally, you need to look out for: -

1. Punctures and Foreign Objects - Large punctures normally manifest themselves quite quickly with a rapid loss of pressure. When objects pierce the outer tyre, this can be very dangerous. Often things like screws, glass shards or pieces of swarf from the road are an indication that you've got a serious puncture.
2. Tyre Sidewall Damage - Any damage to a tyre's sidewall is usually terminal. If you've ever got a little too close to the kerb and heard that 'grating' sound, there is a fair chance that you might have damaged the sidewall of your tyre (as well as your alloys… ouch).
3. Bulges - Tyres should be one shape and one shape only. Uniformly round. If there are bulges, bumps or any sections that otherwise interrupt the smooth curve of your tyre, then it is a surefire sign that your tyre is damaged. This can often be caused by making hard contact with a sharp object… Like the kerb, or even a particularly severe speedbump!
4. Uneven Wear - On inspecting your tyres, you notice that one side has plenty of tread, but there is a smooth section on one side? This is due to uneven wear.

There are also other indicators of uneven tyre wear that you might notice whilst driving. These are things like: -

• A tendency for the vehicle to pull to one side
• Significant vibration

The Effect of Shallow Tyre Tread

Several areas can be adversely affected if your tyre tread is severely worn.

You can expect to see a marked decrease in performance in the following areas: -

• Cornering – Your tyres have less grip. In the worst case, this could result in skidding.
• Increased stopping distance – If your tyres are the legal minimum of 1.6mm, then you need to know this. Your stopping distance is increased by around a third! You should also know that this is not linear. Stopping distances increase dramatically as soon as your drop below 3mm in tread depth!
• Reduced acceleration – If you need to make a swift exit, having reduced tyre tread could increase the chance of wheelspins or even loss of control in extreme circumstances.

Different Tyres on the Same Axle? Not a Good Idea!

While you may find that only one tyre needs replacing, you need to consider replacing both.

Why?

It is not permitted to have tyres with different tread patterns on the same axle. You could try and find a tyre to match the one on the other side.

But here is an easier solution…

Replace both tyres at once. Here are the benefits to doing so: -

• You will be road legal
• You'll ensure equal performance on both sides of your car
• It is easier than trying to source an exact match
• You'll get an overall better driving experience

It is always worth considering replacing all four tyres at the same time. Provided there are no other issues with your vehicle (normally indicated by uneven wear), you can ensure that you get the best performance from each wheel.

Furthermore, you won't be playing a continuous 'catch up' game as the front, or back tyres wear out unevenly.

Can I Ever Have Different Tyres on the Same Vehicle?

Yes, depending on the vehicle, you may find that the manufacturer stipulates different tyres on the front axle and the back. You'll tend to find this is the case in high powered rear-wheel-drive vehicles, which need greater road contact for acceleration.

Other examples could include vehicles that need a slightly higher rear axle.

Tyres and My Car Insurance | Here's the Deal

If you've ever been involved in an accident, you'll already appreciate how important your insurance is. You dutifully pay your premium every year, and you are covered, right?

Not always.

Why?

Insurers will often do their utmost to avoid paying out! They often will focus on tyres as a means to avoid having to shell out for repairs. If you've been involved in an incident and any of the following is discovered, you may find that you'll need to pay for more than a new set of tyres: -

Wrong Tyre Fit

Be sure to stick to the tyres recommended by your vehicle manufacturer. It isn't just about brands either. You'll need to make sure that your tyres are compliant in the following areas:

• Your tyres must be the correct size
• The tyres must have the correct speed rating
• Car tyres must have the correct load rating

Illegal Tyres

It can't be overstated how costly it can be to drive with tyres that are not road legal. Aside from the fact that you or others could be badly injured, other costs must be considered…

• Penalty points -  As we stated above, the minimum legal depth for tyres is 1.6mm. If you are found driving with tyres whose tread is below this level, then you can expect three penalty points on your licence… And that's per tyre!
• Fines – You may also be fined in addition to receiving points on your licence. It's not a small fine either. We are talking somewhere in the region of £2,500. Not total, again that is per tyre. A £10,000 fine is a lot more than it would cost to replace all four wheels!
• Prosecution under the law – Using a vehicle in a dangerous condition carries heavy penalties. It could even result in the loss of your driving licence. If you need to use a car to get to work, think how much this would cost you.
• Invalidated insurance – On top of all of the above, you'll find that your insurance won't cover you if you've been driving illegally.

Suddenly, buying a new set of tyres doesn't seem quite so costly after all?

Original Equipment

Original equipment or 'OE' for short is the term used to describe factory fitted, approved tyres that are specific to certain vehicles. They are often custom-designed for a specific make and model of a vehicle. They may have features such as…

• A specific tread pattern
• A specific compound
• A unique internal construction

OE tyres fall into three distinct categories. It is well worth checking before purchasing new tyres for your vehicle. They are:

• Mandatory OE tyres – This is restrictive and very specific. This tyre can only be fitted to an approved vehicle.
• Technical OE tyres – These tyres are slightly limited but can be installed on other vehicles.
• Free Approval – These tyres can be fitted to any compatible vehicle.

It is worth noting that OE tyres have normally undergone rigorous testing using your exact vehicle and, as a result, can often be a great choice. You'll also get the best driving experience in your vehicle and can rest safe in the knowledge that your car is safe.

How Do I Know if My Existing Tyres Are 'OE'?

You'll find a code or symbol on the sidewall of your tyre. Some large manufacturers always carry the same marking to denote that original equipment tyres are fitted. Here's a table with some examples:

Consider How the Vehicle will be Used

Have a careful think about where you will be using your car for the majority of the time, and then choose a tyre that is best suited to those conditions.

Are you going to be regularly driving on roads, or will your vehicle be used off-road?

While you might think it does not matter, here are some reasons why choosing the right tyre is important in these instances: -

Normal Tyres

These are designed primarily for road use. They will have narrower tread. Normal tyres are generally made with harder compounds, meaning they wear away less quickly. They are also designed to be inflated to a higher pressure.

The downside of using normal tyres off-road is that the tread can quickly become clogged, reducing grip. If you've ever got stuck in a field or grass verge, you'll have witnessed this firsthand.

Off-Road Tyres

Off-road tyres have many key differences when compared to normal tyres. They have…

• Wider grooves and tread – This allows them to avoid mud buildups.
• A larger 'footprint' – In short, they have a greater surface contact with the terrain beneath. Even if the tyre tread is clogged, they will still give excellent purchase.
• They are designed to be used to 'drive' all four wheels. As the term suggests, four-wheel drive is exactly that. Instead of two tyres sharing the work, all four get involved!

The bad news? There are quite a few downsides to using off-road tyres for everyday road driving…

• Because of their larger surface area, they create a lot of friction. This can lead to significant increases in fuel consumption.
• The increased friction will lead to greater tyre wear, meaning they need to be replaced more often.

What's the Weather?

If you are in the UK, it is probably raining.

Joking aside, the conditions you expect to drive in can also influence your choice when purchasing a new tyre. There are generally 3 different types of tyres that are custom made for certain seasons. They are…

Summer Tyres

As the name would suggest, summer tyres are suited to better weather. It is important to note that it doesn't have to be particularly warm to consider using summer tyres. The lowest limit for their recommended use is 7°C.

Why does the temperature make a difference?

It is all about the rubber compound used. As rubber gets cold or warm, its properties change. Summer tyres are designed to be flexible and soft at relatively warmer temperatures. Below 7°C, they harden up and don't give optimal performance.

It is also worth noting that summer tyres are suitable for driving in both wet and dry conditions. 

Winter Tyres

If you expect to be driving in less than 7°C, winter tyres are excellent. In warmer temperatures, the rubber compound is too soft. The cold air ensures that they are just the right level of firmness to offer excellent grip.

Other features of winter tyres include more aggressive tread, designed to prevent aquaplaning and provide superior grip on snow and slush for the best possible traction.

They may even feature small rubber studs to help gain purchase on slippery winter surfaces.

The downside to using them in warm temperatures is that they will be worn away relatively quickly due to the softer compounds.

All-Season Tyres 

All season compounds could be the perfect solution if you live in a climate where the conditions are variable. They provide a good grip in both warm and cold conditions.

But…

You need to know that they are very much a compromise. Being a good 'all round' tyre is adequate, but they don't excel in any particular area. They are generally comfortable and quiet tyres that provide good efficiency in the majority of situations.

How are Tyres Labelled?

Now, it is important not to get confused. The information on the sidewall of your tyre, which we gave you details of above, is entirely to do with compatibility and sizing.

Tyre labelling is something entirely different.

Different? How?

The label that comes on new tyres is a measure of a tyre's performance and efficiency. Each tyre type is given a grade in several areas. These include: -

Fuel Efficiency
This is presented as a coloured scale rating from A to G. You'll see a large black arrow pointing to the relevant grade. "A" is the best, "G" is the worst.

Wet Grip
This is a measure of how quickly the car can stop in wet conditions. It is rated from "A" to "G", with "A" being the best.

Noise
This is a measure of how loud the tyre is on the road. This is one you really need to pay attention to. You'll see a speaker symbol with a rating of A, B or C, along with a noise rating given in decibels (dB). Why is this important? The EU no longer allows class C noise levels!

Mountains?
Tyres suitable for driving in snow will also feature a picture of a mountain with a snowflake inside. Those designed for ice will have another mountain called an 'ice stalagmite'.

The tyre labels have recently been updated. It is important to note that the tyres may be exactly the same whilst the labels and the convention in which they are depicted has changed.

Understanding Tyre Sizes | A Step by Step Guide
 

1) Go to your vehicle and check the sidewall of your tyres. (It's important to note that some vehicles have different tyres on the front and back)

2) You'll see a number written on the side. It will look something like this "225/60R17 99H". These numbers contain all the information you need to know. Here's how to decode it: -

"225": This is the first number in the sequence. It is a description of the tyre's width in MM. In this case, it is 225mm. Another way to think of it is tyre thickness between each sidewall.

"60": This is the 'aspect ratio' of your tyre. Confusingly, this is actually a percentage of the width. The smaller this number, the lower profile the tyre is. 60 means the side profile is 60% of the size of the width, 50 means 50% and so on…

"R17": This is how 'tall' the tyre is, in inches, from top to bottom.

"99": This number relates to the tyres' load rating'. It is a measure of how much weight each tyre can safely bear. Load ratings can get confusing. A general rule of thumb is that the higher the number, the more weight a tyre can carry. Check your car's handbook to find out what limits apply.

"H": This is your tyres' speed rating'. It is a measure of the maximum speed that the tyres are rated for. It is well worth checking the speed rating, even if you have found a tyre with the correct size.

Car Tyre Sizes | Tips and Tricks

The above sounds quite involved, so here are some key pieces of advice to make sure that you get the correct tyre for your vehicle: -

Be sure to see what is already fitted
To make it easier, go and take a look at the tyres already on your vehicle. Make sure that both tyres on the same axle are matching. Look for tyres with the same numbers as those written on the sidewall.

Pay careful attention to the 'R' number
One key thing to focus on is the number beginning with 'R'. As we described above, this is a measure of the diameter of the wheel. Without this being correct, the other numbers will not matter as the tyre won't fit properly.

Use a reliable tyre website
To make life easy, why not consider using an online tyre provider? It's so simple! Here's a step-by-step guide and some of the benefits.

1) Head over to Motokiki

2) Enter your vehicle registration

3) See all the recommended tyre sizes for your specific car!

4) Compare the details between a range of tyres and what suits your vehicle.

There's plenty of benefits to using a good quality online tyre provider: -

• It is quick, easy and convenient. Often you'll be able to find the perfect tyre just around the corner.
• You'll only see tyres specific to your car. Using your registration and an extensive database, you can ensure that the tyres sourced are 100% correct.
• You'll see plenty of options without the hard work. Searching manually can be a chore. Not only do you have to find the right size, load rating and speed rating, you also have to consider brands, seasons and more… Searching online allows you to see all of your options on one screen at a glance.

Replacing Tyres in Pairs

Got one tyre that has seen better days?

It might actually be more cost-effective to replace it as part of a pair.

Here's why…

Improved safety and control
As we said right at the start, your tyres are the only thing keeping you in contact with the road. It makes real sense to ensure that this contact is as stable as possible. Two new tyres are better than one when it comes to keeping a good grip.

You'll save money and time
Imagine going for a run with one old sneaker on one foot and a brand new one on the other. Do you think you'll be in a good position to beat your personal best time?

The same applies to car tyres.

By ensuring a good grip on the road on both sides of the car, you'll be increasing how efficient your vehicle is when it comes to fuel. The result is money in your pocket.

Also…

It takes about the same amount of time to replace two tyres as it does one. It would be a shame to spend time getting a single tyre replaced, only to have to go back relatively quickly to get the other tyre done.

It prevents uneven wear
We talked about uneven wear prior. Your car will have a better grip on one side than the other, creating an imbalance. You'll be making the new tyre do the bulk of the work, and as a result, it will wear quicker and possibly unevenly. By fitting two tyres, you ensure that everything is in equilibrium.

It prevents further maintenance issues
While we are on the subject of things being equal, imbalanced forces are bad for your car. It can affect things like your steering, vehicle tracking, brake wear and even your suspension. By ensuring both sides of the car are 'balanced', you can prevent further, more costly, maintenance issues.