Tyres. They are black, round, and made of rubber. Get the right size and make sure they look good – simple right? Not so!
There’s a lot of thought needed to choose the right competition tyres to buy and in this article we will be exploring exactly what to look for and how to get the most out of them.
Understanding Tyre Regulations
Trying to find a suitable tyre for your type of competition can sometimes be a difficult task. Let’s start with what you need to know regarding your available tyre choice.
The first thing to do is to consult the regulations that are set by your relevant motorsport governing body. For competition in the UK, these regulations are set by Motorsport UK.
As part of these regulations, the governing body will have formulated a series of lists which contain tyres that are suitable for various types of competition.
Examples of these being:
- List 1A – all tyres suitable for production-based championships.
- Lists 1B & 1C- sports or uprated tyres which are suitable for competition.
- Lists 3 & 5 include tyres suitable for off-road events such as rallying and cross country.
You will need to check which lists your championship allows before selecting your new tyres. There are some championships that may run a “control” tyre which all competitors must use. If this is the case then it makes your tyre choice much more straightforward!
For those who are allowed a choice of tyres then at the bottom of this article we’ve compiled the 2022 Motorsport UK lists alongside tyres that we offer so sizes and prices can be easily checked.
If you are doing track days you will just need to check if road legal tyres are required, this will be determined by the organisers of the event. 99% of Track day tyres are E marked as road legal so they can be used to drive to the event.
What tread pattern should I use?
One of the first things that you will notice when looking for tyres is the diverse range of tread patterns which are available. Do these really make a difference? They absolutely do!
To lay it out in simple terms, you can separate the different tread patterns used for circuit racing into 3 groups.
- Dry weather
- Fully wet weather
For rallying, there are two types of tyre available, gravel or tarmac. These divide further as some gravel tyres are aimed for hard packed or loose surfaces.
Circuit Racing Tyres
Dry Tyres – AKA “Slicks”
Dry tyres have no grooves and feature a completely smooth surface; the advantage of this is a very large amount of grip as a larger amount of rubber is in contact with the road.
However, as soon as water appears on the racing surface, and the tyre temperatures start to drop, these tyres will quickly lose their grip. This is due to the tyre being unable to cut through or clear the water from the track surface.
Wet Tyres – AKA “Wets”
Having the sole purpose of being used in wet conditions, these tyres have the most aggressive tyre tread pattern available. Deep vertical grooves help cut through standing water and a series of curved grooves will help shift a large amount of water outwards away from the tyre.
Simply put, these are designed to provide the best grip in the worst conditions.
Multipurpose Tyres – AKA “Semi-Slicks”
These are treaded tyres with grooves for wet conditions but also have a large amount of tyre surface area in contact with the tarmac to provide high levels of grip in the dry. They are good all-round tyres which are ideal for championships where pit stops are not possible. Many of these tyres also double as track day tyres.
Rally – Tarmac Tyres
Not the same as circuit tarmac tyres! Longer stages have the potential for weather changes and the possibility of gravel on the surface, meaning slick tyres may become dangerous to use. Therefore, tarmac rally tyres feature grooves which will provide some grip in slippery conditions.
Rally – Gravel Tyres
These tyres feature a more aggressive tread block pattern, designed to cut through the gravel and mud found on forest stages. They’re super important as they massively increase traction and braking stability on loose surfaces. Gravel rally tyres also tend to feature reinforced sidewalls to help protect from cuts and impact punctures which can occur from sharp rocks and broken surfaces on gravel roads. Gravel tyre treads vary, some are aimed at loose gravel or muddy surfaces, and others for hard packed surfaces. Follow the links on List 5, found at the end of this blog to see details of the intended surface use.
What Tyre Compound Do I Need?
Some of the tyres which are more geared towards competition or track day use are available in various compounds. These compounds are usually referred to as soft, medium, or hard, relating to the construction of the rubber tread.
The general “rule of thumb” goes something like this…
- Soft Compound = more grip + shorter life
- Hard Compound = less grip + longer life
However, it is not as straightforward as simply choosing a soft compound because it has the most grip, there are a lot more variables which need to be considered including surface type (smooth or abrasive), weather conditions (wet, damp, or dry) and expected temperature.
The surface types to consider are slightly different when competing on tarmac where you will need to find a compromise between surface type and weather conditions. When on gravel, different considerations are to be made as the weather and surface conditions makes for a more involved decision on what compound to use.
Durometers can be a very useful tool for comparing tyre compounds (or checking if compounds have changed due to age etc).
Maximising Tyre Performance
There is more to improving the grip from your tyres than simply selecting the best compound for your requirements or application.
As tyres are a highly dynamic part of the car, their effectiveness is dependent on several factors that you need to be aware of to fully understand how a tyre behaves and why.
As your tyres are the only form of contact with the road, they have the sole responsibility of maintaining sufficient friction to keep the car moving in the correct direction.
Even though, at face value, the tyres are quite a large item, the actual amount of tread which is in contact with the road is only about the size of an A4 sheet of paper, and even less for smaller tyres. Making sure you can get the most from this very small surface area of tyre on the road is critically important.
You guessed it… tyres need air to function correctly!
Once you have set the amount of air pressure that you want in the tyres, it is important to note that they are not going to stay that way once you start driving. As a result the handling characteristics are also going to change.
Tyre pressure and temperature impact each other immensely. A small amount of heat is generated by the movement of the tyre and it’s this increase in heat that will also increase the tyre pressure.
High tyre pressures stiffen the side wall and will reduce the amount of flex in the tyre when under load, which can increase the stability of the car while cornering. It can also lead to increased feel and responsiveness through the steering wheel.
Too much heat will cause a lack of grip though so it’s important to find the temperature sweet spot!
Lower tyre pressure can lose stability through a corner due to the tyre moving around a lot more – think of it like having the car sitting on jelly! This lack of stability is also transferred back through the steering wheel to the driver decreasing feel and response. Lower pressures will create more drag and in extreme cases can cause the tyre to fall off the rim.
It’s important to check your tyre pressures often with a gauge. One common trick is to set your tyre pressures a little on the low side when cold so that they reach the optimum pressure (and tyre temperature) when you are on track or stage.
Camber / Caster Angles
Another way to improve the performance of your tyres is through changing the camber or vertical lean angle. The camber is a measurement of the angle between the top and bottom pivots on the steering
If the tyre is sitting completely vertical, this is measured as zero camber. This means that the full surface of the tyre is in contact with the road and has the maximum amount of the contact patch and grip available. If the top of the tyre angled towards the car, this is known as negative camber, while positive camber is when the top of the tyres is angled away from the car.
Race cars are set up to have negative camber. This means that on the straights, the car is running on the inside edge of the tyre, but through the corners a larger part of the tyre is in contact with the road surface. This provides better cornering grip and lessens the rolling resistance while on the straights, (increasing top speed).
Like any setup changes though there are compromises.
Despite the benefits, having increased camber angles can play a part in increasing the tyre wear, particularly on the inside edge of the tyre. Be mindful that adding more camber will also affect the braking performance. On the track this is preferable to zero camber and positive camber because this can result in a loss of grip when cornering as not all of the surface area of the tyre is not in contact with the road.
It is possible to have the benefits of negative camber on some vehicles by increasing the camber angle. This can be achieved via bushes where available by the following brands:
This can also be achieved via top mounts and replacement bracketry. Please contact us for further details.
How Long Do Race Tyres Last?
The life of a tyre depends on a lot of different factors, some of which are mentioned above. Most of these factors can be divided into the following groups.
Many factors can affect tyre wear. Firstly, the ambient temperature. This plays a part in the starting temperature of the tyre, which also changes with the track temperature. This change in temperature can affect the amount of grip, with higher temperatures producing a greater amount of wear.
The level of abrasion on the track surface will also affect tyre life. Not all tarmac has the same surface properties so the tyre wear will vary at different venues.
Also, a larger number of high-speed corners will cause the tyres to wear quicker, while tracks with less corners will be better on tyre wear.
The suspension and steering geometry can have an input on the life of a tyre. Large camber angles, castor angles, and toe in/out all play a part in how long the tyres will last. Running higher camber angles means that the tyre is running on the inside edge much more than the rest of the tyre, causing it to wear out much more quickly.
The other main tyre wear factor is toe-in/out. This is the angle of the wheels in relation to the axle of the car. With the wheels completely parallel, this is toe neutral. When the leading edge of the tyre is pointing towards the centre of the car, this is known as toe-in, while toe-out is when the leading edge is pointing away from the car.
Toe-in is used to help with better stability and grip while entering a corner, but the resulting angle of the tyres in a straight line means that the amount of tyre wear is increased.
Link to wheel alignment products.
Another potential element to affect tyre life is the driver’s inputs. Being over enthusiastic with your right foot and spinning the wheels, locking the brakes or harsh inputs with the steering wheel can all lead to reduced tyre life. This is because you are causing the tyres to work harder and can result in an increase in heat and therefore, more wear.
So, there you have it! your guide to tyres and what to look for. If you are unsure about any part of this article, our specialist tyre sales team are available to take your questions and make recommendations.
Tyre valves are often a forgotten part of the tyre fitting process; rubber valves should always be replaced every tyre change as they deteriorate due to UV and brake dust and other contaminants. A short valve is always a good idea as it is less likely to come into contact with kerbs or other competitor’s wheels! A popular upgrade is to fit steel or alloy bolt in valves as these are much more resistant to deterioration than rubber valves. An added benefit is they are not affected by centrifugal forces at very high speed. They also look much nicer!
Useful links to our List 1 A Tyres
Continental: EcoContact EP , SportContact 2 , PremiumContact , EcoContact 3 , SportContact 5 , PremiumContact 5 , EcoContact 5 , PremiumContact 2 , SportContact 3, Sport Contact 5P , SportContact 6 , PremiumContact 6 , EcoContact 6 , SportContact 7
Goodyear: Eagle F1 Asymmetric 2 , Eagle F1 Asymmetric 3 , Efficient Grip Performance , Eagle F1 SuperSport , Eagle F1 SuperSport R , Eagle F1 SuperSport RS , Efficient Grip Compact , Eagle F1 Asymmetric 5
Hankook: Ventus S1 Evo2
List 1 B Tyres
Cooper: Rally Classic CT01 (pre 1/10/90)
List 1 C Tyres
Dunlop: Direzza DZ03G
MRF: ZTR Trackday
LIST 3 Tyres for Sporting Car Trials
Vredestein: T-Trac 2
LIST 5 Tyres for Cross Country Events
Cooper : Discoverer Gravel DG1
DMACK : DMG1
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