Simulation racing is a growing sport and the increasing complexity of the games means that they are now very close to real life racing. They offer multiple set up alteration options which change the vehicle dynamics as they would on your very own car. They are a great way to practise a new circuit and to try some set up alterations ahead of a race.
This article will look at what aspects of geometry are most commonly adjustable on games such as Assetto Corsa, iRacing and Project Cars to provide an explanation as to what each area of adjustment is and what each adjustment will do to the setup of the car. The layout of this document is to be an easy to navigate user guide which can be referred to whilst you are making adjustments on your sim.
When would I need to change the setup?
There are a few reasons why you will need to alter the setup of your car when racing. The main reasons are:
- Handling issues – if you are suffering from oversteer, understeer, wheel spin, brake lock up, bumpy ride or sluggish handling then you will want to make some set up alterations to make your car faster.
- A circuit change – if you are going between circuits from a circuit with tight corner sections with short straights to a circuit with long fast straights and fast shallow corners you will need to alter your set up. Likewise, if you are going from a smooth circuit like Silverstone to a bumpy circuit like Nurburgring Nordschleife you will need to make some changes to your setup.
- Weather change – if the weather changes between races or during a race you will need to alter the set up to cope with wet/dry weather and cold/hot weather.
- Driver preference – you as a driver are a key part to the setup and handling of the car and might want to make changes to provide you with more feedback from the car.
Adjustable Suspension Options
Sim racing now comes packed with multiple options of adjustment when it comes to vehicle set up. We have detailed below what each one is before we look into the effects of the adjustments.
- Camber – camber is the angle of the wheel when viewed from the front of the car. If the top of the wheel leans in towards the centre of the car, this is called negative (-) camber. If the top of the wheel leans out towards the outside of the car it is called positive (+) camber. If the wheel is stood up perfectly vertically then the wheel has zero camber. Negative camber is the most common setting on a race or track car. The GIF below shows negative camber increasing and decreasing.
- Toe – toe is the angle of the wheel when viewed from above. The best way to envisage toe is to think of the wheels steering inboard or outboard of the car. This is toe angle. The GIF below shows changing toe angle from above. Toe in (or positive toe (+)) is where the front of the wheel points in towards the centre of the car from a top view. Toe out (or negative toe (-)) is when the front of the wheel points out towards the outside of the car from a top view. There are many different ways to set toe on the front and rear wheels and not one rule applies to all cars.
- Caster – caster angle is only present at the front wheels and is a little more complex than toe or camber. For a MacPherson strut vehicle a line can be drawn down the length of the damper from a side view down to the ground. The angle at which this line leans away from a perfectly vertical line is the caster angle. For a double wishbone set up a line is drawn from a side view through the upper and lower wishbone points where the upright mounts to them. Again this is drawn to the ground and the angle of this line relative to a perfectly vertical line through the centre of the wheel is the caster angle. If the line leans towards the back of the car it is called positive (+) caster. If the line leans towards the front of the car it is called negative (-) caster. The vast majority of cars use positive caster. The GIF below shows caster angle changing on a Porsche with McPherson Strut suspension.
- Bump – Bump (or compression) damping controls how quickly the damper compresses and controls how the wheel moves upwards. The wheel will move upwards during cornering on the outside wheels, under braking on the front wheels and under acceleration on the rear wheels. Soft damping (0) allows the damper to compress quickly; stiff damping (10) resists the damper compressing making it stiffer.
- Fast Bump – Fast bump is the same as high speed bump (or compression) damping. It comes into effect over bumps or kerbs out on circuit and alters how quickly the damper compresses over these sections. Again low numbers make the damper softer and higher numbers make the damper stiffer.
- Rebound – Rebound damping controls how quickly the damper is able to extend. The damper will need to extend after the wheels have been compressed or during cornering on the inside wheels as the car leans, under braking on the rear wheels and on acceleration on the front wheels. Low numbers make the damping soft, allowing the damper to extend quickly with low resistance. High numbers stiffen the damping and resist the damper extending.
- Fast Rebound – Fast rebound is the same as high speed rebound damping. It comes into effect over bumpy sections after the damper has been compressed rapidly and needs to extend equally quickly to maintain contact with the road surface. Low numbers allow the damper to extend quickly and high numbers resist the extension.
- Spring or Wheel Rate – The spring rate is the stiffness of the coil spring. This determines how stiff the ride of the car is and plays a part in the cornering stiffness of the car. The higher the number the stiffer the coil spring and the lower the number, the softer the coil spring. Wheel rate is the effective spring rate present at the wheel. It uses the installation ratio of the spring to determine the stiffness at the wheel. Due to the leverage that the wheel has over the spring, the wheel rate is often softer than the coil spring that is installed.
- Anti-roll Bar Stiffness (ARB) – The anti-roll bar, ARB or sway bar stiffness refers to the spring stiffness of the anti-roll bar. The anti-roll bar only comes into effect when cornering and stiffens the front or rear axle in a cornering situation and prevents roll. The higher the value for the ARB, the stiffer the anti-roll bar is. The lower the number, the softer it is.
- Ride Height – The ride height refers to the height of the chassis from the ground. The front and rear ride height can be set differently to each other. If the rear is higher than the front, this is referred to as positive rake angle. If the front is higher than the rear, this is known as negative rake angle.
- Packer Rate – Packer rate is also known as bump stop rate. It refers to the stiffness of the bump stops. Bump stops are the rubber stoppers mounted to dampers or suspension components that are contacted when the damper reaches maximum compression. Once engaged, the damper becomes redundant and the packer rate determines how the car will handle. It is a component mainly used and tuned on high downforce cars.
- Travel Range – Travel range refers to the amount of movement that the damper has before contacting the bump stops and bottoming out. The higher the number, the longer the damper is able to travel and the lower the number, the shorter the distance that the damper can travel.
- Pressure – Pressure refers to tyre pressure. If the tyre pressure is too high then it will be overinflated and only the centre of the tyre will be in contact with the ground, raising the two outside edges. An underinflated tyre will lift the centre of the tyre and reduce grip again. A correctly inflated tyre will maximise contact patch. The higher the number, the higher the tyre pressure. Tyre pressure can also be used to control tyre temperatures.
- Aero Downforce – Aero downforce relates to the downforce at the front and rear of the car being generated. This downforce might come from a rear wing, front splitter or underbody aero. A higher number will increase downforce and a lower number will decrease downforce. Downforce effectively generates more mass on the front and rear wheels pushing down on the tyres to increase grip.
- Brake Bias – Brake bias controls how much braking force goes to the front or the rear tyres. It is based upon a percentage or a ratio. A front to rear ratio of 40:60 will send 40% of the brake pressure to the front wheels and 60% to the rear.
- Mass Balance – The mass balance of the car refers to how the car is corner weighted. It is stated as a percentage of the overall vehicle mass. A front to rear mass balance of 45:55 means that 45% of the total vehicle mass is present at the front wheels and 55% is present at the rear wheels. There is also a left to right balance which works in a similar way, if the ratio is left to right of 45:55 then the two left wheels will carry 45% of the total mass and the right wheels will carry 55% of the total vehicle mass.
The effects of adjustment
Now we have covered what each adjustable option means we can take a look into how adjusting those aspects affects the handling of the car so you will be able to fine tune your set up and remove any handling issues you are facing. For more detail and specific help for your vehicle platform our “Adjust and Tune” section goes into greater detail in each of the below areas.
When tuning the different settings always start towards the lower/central setting and make incremental changes up to the point where grip begins to be lost and then come back to the setting that provided the most grip. If you make large multiple changes at once you will not know which change provided a benefit.
- Toe in – Toe in on the front wheels of a car will make the vehicle more likely to understeer on turn in. However, it will create a more stable steering wheel on straight sections at speed, providing more confidence in the car to achieve a higher speed on the straight sections.
Toe in on the rear wheels is a common application on RWD cars as it reduces the tendency to oversteer on corner entry. Too much toe in will generate understeer. Toe in on the rear wheels will also produce stability on straight sections and through long fast corners, helping to keep the rear of the car stable to achieve a higher speed through the corner.
Toe in on the front or rear wheels will increase tyre temperatures due to the tyre scrubbing so keep an eye on tyre temperatures.
- Toe out – Toe out on the front wheels is a very common setting on all platforms as it reduces understeer and makes the car turn in much faster making the car feel more agile. It is more common on FWD cars as they need toe out to reduce understeer due to the front wheels doing much more work than other platforms. Toe out on the front will make the car feel unsteady on straight sections and through fast corners and will scrub some speed off the car particularly through fast corner sections.
Toe out on the rear wheels is very common on FWD cars. It is there to help rotate the rear into corners towards the apex reducing understeer. It also allows more speed to be carried through tighter sections as the rear is actively rotating and not sliding. On the rear of RWD cars it can cause oversteer which should be avoided when racing.
Toe out on the front or rear wheels will increase tyre temperatures which can be both a positive and a negative and is covered in the “Changes for Circuits” section below.
- Camber negative – The vast majority of race and track cars run negative camber to maximise cornering grip. As a rule of thumb, if you install stiffer coil springs, you stiffen the antiroll bar on a particular axle or you run on a tyre with more grip, then you can increase the negative camber as the vehicle will roll onto the contact patch more than before. However, there is a limit at which the grip will begin to reduce again when too much camber is being used and the car will go past maximum lateral force capabilities. Apart from the car losing grip when you have too much negative camber, you can also tell as the tyre will begin to overheat on the inside edge and will break down and likely blister.
More negative camber is used on the front wheels of RWD cars than on FWD and 4WD cars. This is because too much negative camber on the driven wheels will reduce straight line grip due to the lack of contact patch when going in a straight line. Similarly, more camber is used on the back wheels of a FWD car than a RWD car for the same reasons.
- Camber positive – Positive camber is a less popular setting. However, it is used in some areas of motorsport. On oval racing cars positive camber is often set on the inside two wheels. This is due to the car only ever turning in one direction on banked corners loading up the outside wheels of the car and maximising all contact patches. Positive camber is also used on the rear of some drift cars that have a lot of camber gain in the rear suspension geometry. Due to the soft coil springs and large amount of suspension travel at the back wheels, positive camber is set statically to increase grip as the car squats on throttle.
Positive camber set on a circuit car will lose grip and cause poor handling as the car will roll off the contact patch further reducing grip and cause the car to slide. It will also overheat the outside edge of the tyre, causing blistering or tyre damage as it will overheat.
- Caster angle – adjusting caster is not possible on all sim racing platforms and the cars within them. If you are able to adjust it then you will benefit from it. Increasing the positive caster will provide the car with more stability in straight line sections, increase corner exit stability as the steering wheel straightens naturally and will help increase camber when cornering on the outside wheel so less static camber can be used on the front wheels for straight line grip.
However, too much caster will begin to reduce grip levels as it will unsettle the car during cornering and generate too much camber in the corner. The feedback through the wheel can also become too much for driver strength on endurance races. It is usually best to run a high amount of caster but when the car begins to feel unstable through high speed corners, reduce the caster back slightly.
- Spring rates and wheel rates– In general a softer spring rate provides the car with more grip. This is due to the axle carrying less lateral load transfer through corners and the softer spring absorbing more of the bumps and undulations in the circuit. However, if the spring is made too soft then the car can bottom out, slowing the car down and it can roll too much and pitch and heave on brakes and throttle, lifting wheels in the process so a happy medium needs to be found.
A stiffer spring allows the car to be lowered closer to the ground, lowering the centre of gravity, increasing cornering performance. A stiffer spring also helps to keep the car stable on throttle and brakes preventing the car unloading wheels in these situations and maintaining grip. Stiffer springs will also reduce roll when cornering helping to run a lower ride height further as the car is less likely to bottom out. If you run the car too stiff, it will begin to skip and hop over bumps, losing grip and making the car slower.
In general different springs are used on the rear axle and the front axle. As a rule of thumb a FWD car will have a softer spring/wheel rate at the front wheels and a stiffer spring at the rear as this will help to reduce understeer and increase front end grip. For a RWD car, a softer spring is usually used on the rear axle and a stiffer spring on the front axle. This will reduce oversteer and increase rear end grip.
- Anti-roll bars – Anti-roll bars are a fundamental tuning tool when improving the handling of the car through the mid-corner section of a corner. If the anti-roll bar is set too stiff then too much lateral load transfer will occur and the car might lift wheels off the ground whilst cornering. This will ultimately reduce grip. If they are set too soft then the car will roll too much and could cause bottoming out and will reduce driver confidence due to the sensation of the excessive roll.
With anti-roll bars it is more important to tune the relative stiffness front to rear. It is the difference in how stiff the front is in comparison to the rear that really matters. For example, a car with a stiffer anti-roll bar at the front compared to the rear will increase understeer but reduce oversteer. A car with a stiffer anti-roll bar at the rear than the front will have a tendency to oversteer and will reduce understeer. Tuning this balance is where the time should be spent to fine tune mid-corner handling.
- Damper Bump – The damper settings play a large part in fine tuning the handling of the car, particularly for corner entry/exit handling issues. As well as cornering, the damper settings also affect how the car reacts to braking and acceleration. A high number will stiffen the bump damping and a low number will soften the bump damping. In general, softer damping will provide the car with more grip and will help to reduce tyre wear as the tyre is less stressed.
Stiffer damping makes the car more reactive and makes the car feel more stable when changing direction. If you are experiencing oversteer or understeer on the corner entry/exit sections then softening the front dampers or stiffening the rear will reduce understeer. Likewise, softening the rear and stiffening the front will reduce oversteer. If you decide to run a stiffer spring/wheel rate then the damping will need to be stiffened slightly to compensate too.
- Damper Rebound – Having a soft setting for rebound will generate more grip at the wheels. Therefore, softening the front dampers will reduce understeer and softening the rear dampers will reduce oversteer. However, having rebound set too soft will make direction changes sluggish and could cause the suspension to become bouncy as the spring is not being controlled enough when extending after a compression.
A stiffer setting for rebound will produce better direction change from the car being more stable through chicane sections. A higher value at the rear wheels will also make the car less stable under braking conditions as the rear dampers aren’t able to extend quickly enough to keep the wheels in contact with the ground. This can cause a rear lock up and cause a spin.
- Damper FST Bump – In most cases you will want the FST bump set to a softer setting. This is because it allows you to run a stiffer bump setting but keeps the damper softer when it hits a bump or a kerb out on circuit and is shocked quickly. Usually with a stiff bump setting the bumps and kerbs will bounce the wheel off the ground and break traction. With a FST bump option you are able to remove this side effect and allow the damper to absorb fast bumps out on circuit.
Provided your FST rebound settings are correct you can run this quite soft. If FST rebound is unavailable then you can’t go too soft otherwise the spring will bounce back too quickly after a bump and can cause the car to hop and be unsettled. For extremely smooth circuits you could stiffen up the FST bump slightly to increase handling precision.
- Damper FST Rebound – FST rebound controls how the damper extends after a bump or kerb has compressed the damper. If like in most cases you have the FST bump set quite soft then the FST rebound would also be set quite soft to allow the damper to extend quickly in time for the next bump or kerb on the track. However, if it is set too soft then the damper can extend too quickly and cause the tyre to bounce back off the circuit making the next bump effectively larger, unsettling the car and reducing grip.
Running a stiff FST rebound removes the potential for a bouncy car and controls the spring better as it returns to the ground. However, running it too high can cause suspension creep. This is when a bump compresses the damper and before the damper has extended fully it hits the next bump and compresses further. This repeats until the suspension is bottomed out on the bump rubbers and there is no more bump travel available making the car very stiff. Therefore a middle ground needs to be found between a bouncy set up and a creeping set up to have the optimum setting.
- Packer Rate – Packer rates are most used on aero cars with high amounts of downforce and only work when the downforce is working at high levels at high speeds. A high value reduces damper movement once the bump stop is engaged and stiffens the car up under aero load. This decreases aero pitch and increases handling responsiveness. A stiffer front end also makes the car more stable under braking conditions at speed.
A softer packer rate increases aero pitch sensitivity and will increase traction. The front and rear can run different values to help shift handling balance from front to rear. A stiffer packer at the front will reduce oversteer and a stiffer packer to the rear will reduce understeer and will produce a more predictable front end. A softer packer will also provide a more comfortable and stable transition from the damper working to the bump stop taking over the damping attitude of the car and will increase stability at this point of transition.
- Travel Range – this dictates how much travel the damper has before contacting the bump stops. This needs tuning in accordance with the ride height of your vehicle. If you are running very low to the ground, in a car like a formula car or a high downforce car, then you will want to reduce travel so that the car does not bottom out on the ground. If you are running a slightly higher ride height, like in some GT cars or fast road cars, then you will want to run a higher damper travel to provide more traction and allow the damper to control more of the chassis movement.
- Mass balance – The ideal mass balance for many race cars is a 50/50 front to rear mass split and a 50/50 side to side mass split. If you are experiencing wheel spin on a FWD or RWD car then you should shift some mass to the spinning wheels but only move mass in small amounts as it will make a big difference in how the car handles. Also, if you have a lot of rear downforce being generated but not much front downforce and you are unable to alter the difference then you can shift more mass to the front of the car to even out the grip at high speed once the rear aero begins working.
- Aero Changes – The aero changes available in sim racing tend to be more or less downforce at the front and the rear of the car. Less aero will produce more top speed on the straights as it will reduce drag. However, for more cornering speed, more downforce will generate more grip and therefore more cornering speed through mid/high speed corners.
You can use the front and rear downforce to fine tune the handling of the car through mid/high speed corners. If you are experiencing understeer in these corners then you can increase front downforce. If you are starting to oversteer then you can increase rear downforce to provide the rear with more grip.
- Tyre Pressures – your tyre pressures are very important in controlling grip levels and maintaining the life span of your tyre throughout a race. As a rule of thumb you should aim to have your tyre pressures running at a hot pressure of between 28-32 degrees or as the tyre manufacturer recommends. If you’re using a particular tyre then google the specs for that tyre.
Tyre pressure can also help to control the temperature of your tyre. Once you are operating in the correct hot pressure range you should look at your tyre temperatures. As a rule of thumb you should have a road/track tyre in the region of 70-85 degrees C, semi slick track tyres should be in the window of 70-95 degrees C and slicks can be hotter in the range of 90-110 degrees C. If you want to increase the life span of the tyre then run the tyre at the colder end of the scale. If you want maximum grip for sprint races operate at the higher end of the scale. To increase and decrease the temperature you can slightly increase tyre pressure to heat the tyre more or decrease it slightly to lower the temperature. More downforce and more toe/camber angle will also help to increase tyre temperatures. If you go too far with pressures and over/underinflate the tyre then you will see large spikes in tyre temperature due to over working a small area of the tyre.
- Brake Bias – The brake bias can be adjusted towards the front or rear wheels to change how the car enters a corner and to control wheel lock up. If you are locking up your front or rear wheels when braking hard into a corner then shift the bias towards the non-locking wheels. This will even out the braking forces and prevent wheel lock up and loss of grip.
If you are experiencing understeer on corner entry after being hard on the brakes then you can move more bias to the rear of the car. If you are experiencing oversteer after being hard on the brakes then you can move more bias towards the front of the car. Only move the bias in small amounts otherwise you might upset the handling of the car.
Oversteer and understeer
The information below is a generalisation of how to reduce oversteer and understeer on most platforms. For more specific information and more detail on how to reduce oversteer and understeer check out our full article on oversteer and understeer linked at the bottom of this article. For solving understeer and oversteer you need to recognise where in the corner it is happening. The below solutions are therefore sectioned into “corner entry/exit” and “mid corner” due to the solutions being different for each scenario.
- Reducing Understeer
Corner entry/exit understeer solutions
- Increase front damper rebound stiffness
- Reduce front ride height
- Increase front caster angle
- Increase front toe out
- Increase front downforce
Mid-corner understeer solutions
- Soften front anti-roll bar or stiffen rear anti-roll bar
- Soften front coil spring rate
- Reduce front compression stiffness slightly
- Reduce front ride height
- Check front camber angle, tyre wear can be a key indicator
- Reducing Oversteer
Corner entry/exit oversteer solutions
- Lower the rear ride height
- Install softer rear coil springs
- Reduce rear damper compression stiffness
- Increase rear toe in
- Increase rear downforce
Mid-corner oversteer solutions
- Soften rear anti-roll bar or stiffen front anti-roll bar
- Soften rear coil spring rate
- Reduce rear ride height
- Check rear camber, tyre wear can be a key indicator
Changes for Circuits
When moving between different circuits it is ideal to alter your set up to suit the different demands that each circuit has to offer. It will take too long to provide set up tips for each and every circuit so instead we are going to suggest some changes to make when moving to different styles of circuit.
- High average speed circuits to low average speed circuits – set ups for fast circuits like Monza where there are very long straight sections that require a high top speed are very different to that of set ups for circuits like Oulton Park which is slower with tighter twisty sections. For circuits where top speed and long fast corners are the winning factors you will need to make some set up changes to suit. First reduce aero downforce as this will reduce your drag and increase your top speed. Another drag reducing factor is toe. You should reduce front toe close to 0mm or have some slight toe in to provide the steering with stability at top speed. At the rear of the car give the rear wheels slight toe in as well as this will keep the back of the car stable through the long fast corners and allow you to commit to more speed through those corners. If caster is adjustable then increase caster heavily as this will help to keep the steering straight on the long fast sections and the small changes in steering angle will keep the side effects of large caster minimal. Camber settings will need to be slightly less than that of a slower tighter circuit to increase contact patch on the brakes so you can brake later and harder at the end of the long straights and apply throttle more heavily and maintain traction for faster acceleration.
For tighter twisty circuits with smaller straight sections you can run a much more aggressive set up to increase turn in speed and maximise cornering performance. First of all increase your downforce at front and rear as this will generate more cornering speed. With that complete, increase negative camber at the front and rear. This will help increase contact patch as you carry more speed through the corner and roll onto the tyre. Next increase toe out at the front wheels. This will help for initial turn in and will help to reduce understeer. If you have a FWD then some toe out at the rear wheels will also help to remove understeer and improve corner entry handling. For a RWD car slight toe in will still be ideal to keep the rear in control and to prevent oversteer.
- Smooth circuits to bumpy circuits – If you don’t alter some of your set up when moving from a smooth circuit like Silverstone to a bumpy one like Sebring or Nurburgring Nordschleife then you will have handling issues and will have an uncontrollable car. One of the first changes to make is to install softer coil springs and to soften the bump and rebound damping of the car. This will help to absorb the bumps and undulations of the circuit without bouncing the tyre off the ground and losing grip. You will also want to soften off the FST bump and FST rebound so that high speed impacts are quickly absorbed and controlled without affecting the cornering, pitch and yaw conditions of the car too much. Also, slightly increasing ride height can help so that the car does not bottom out with the softer springs now installed. For a high speed bumpy circuit with high aero, install a softer packer rate so that the car can stay relatively soft over bumps once the aero has bottomed out the dampers on the bump stops.
- Sprint to endurance race – When moving from a sprint racing series to an endurance racing series there are some alterations that can be made to increase the life span of your tyres to maintain grip for longer periods. First of all, a softer damper/spring setting will help to remove some of the load from the tyres, allowing the damper and spring to absorb some of the energy in the system. Reducing toe and camber will also help to reduce tyre temperatures, keeping the compound cooler and less likely to overheat and go off. Reducing the downforce will also help to use less fuel and will cause less strain on the tyres helping to stay out on circuit for longer between pit stops. Keep an eye on the tyre temperatures and tune the toe and camber to keep the temps moderate to increase the life. Don’t reduce them so much that you lose grip as they are running too cold though.
Weather can change in the middle of a race and cause chaos on circuit due to all the dry set ups not being able to cope in the new conditions. There are also changes for cold circuits which can happen when moving between countries or even during 24 hour races with hot desert day time temperatures and freezing cold night time temperatures.
- Wet weather changes – when wet weather arrives it can come in form of heavy rain or a light drizzle making the circuit greasy. If heavy rain arrives then install wet tyres as soon as possible. Wet tyres help to disperse water from the surface to allow the softer rubber to grip with the tarmac. If greasy or slightly wet conditions occur then install intermediate tyres if they are an option. For many intermediate tyres will not be an option and for some, wet tyres won’t be an option.
Once tyre changes have been made where possible you can turn your attention to set up changes. First of all you will want to soften off your anti-roll bars front and rear in order to aid cornering grip. Softening the dampers and installing slightly softer springs will also help with straight line grip on throttle and during braking allowing the sprigs and dampers to absorb some of the vehicle energy to relieve the tyres slightly. With the softer set up you can now reduce the negative camber settings all round as the car will be cornering with less speed and less G, so the vehicle will have less tendency to roll and will roll within the dampers now that everything is softer rather than staying stiff and rolling the car onto the contact patch.
The wet surface will also be constantly cooling the tyres which will bring the temperature too low and will reduce grip levels. A way to counteract this is to slightly increase tyre pressure due to pressure, volume and temperature having a fundamental relationship of physics where if the volume remains the same (the tyre size) then an increase in pressure will result in an increase in temperature and vice versa. Don’t over inflate the tyre though as this will have an opposite effect and will lose grip due to the lack of contact patch. Another technique to increase tyre temperatures is to increase toe in on the front and rear axles. The toe in will help with stability on the straight sections and faster corners in the unpredictable conditions and will also scrub the contact patch, increasing the temperature of the tyre and increasing grip. Be careful not to run too much as it could tear the tyre surface and ruin the tyre early in the race.
- Hot to cold weather changes – during endurance races it can be quite common for circuits in places like Dubai or Australia to have dramatic temperature changes on the track surface as the race moves into the cold night. As this happens the tyres will also run at a cooler temperature but if the weather remains the same, a geometry change could totally change how the car handles which is not desirable.
As mentioned in the wet weather section, increasing tyre pressures slightly will help the tyre to increase in pressure due to the volume remaining fixed and the temperature therefore must increase in the air inside the tyre. However, this is an area shrouded in debate as some tyres increase in temperature with some pressure released form the tyre. This is due to the contact patch being able to move around and distort more, increasing the friction between layers in the tyre and generating heat in the compound. Therefore the best thing to do ahead of an endurance race is to select a hot circuit and a cold circuit and tyre increasing and decreasing pressures when moving to the colder climate and seeing which technique works for your particular compound. You will know which works best by keeping an eye on the tyre temperatures. Make sure not to increase or decrease pressures too much otherwise the tyre will lose grip doe to over/under inflation.
Now get racing and feel how all of the above changes work and start winning races!