How To Setup The Perfect Tyre Pressures In ACC

It doesn’t matter whether you’re using a downloaded car setup, the in-game default setups, or creating your own. One thing remains constant. And that is the need for perfect tyre pressures.

You tyre pressures are crucial to your pace in ACC, with cold or hot tyres not providing the ideal levels of grip. Setting the incorrect tyre pressures is often one of the main causes for overheating tyres, and its something we can learn to fix very easily.

In this setup guide, I’m going to look at why tyre pressures are so important. I’ll show you how to calculate the perfect tyre pressures in ACC, and how to find the perfect tyre temperature window.

TL;DR – The perfect tyre pressures for ACC

Before delving into why tyre pressures are so important and how to diagnose any tyre temperature or pressure issues. I first want to show you the best tyre pressures for all cars in ACC. Aiming for the following tyre pressures after completing a few laps in a practice session will get you into the right tyre window.

Optimum dry tyre pressure window

The optimal tyre pressure range in Assetto Corsa Competizione is between 26.0 and 27.0 PSI, and this is the same across all car classes.

The recommended optimum tyre pressure window above is based on the latest version of the DHF tyre compound that was introduced with the v1.9 patch in 2023. Previously, the old 2020 tyre compound (DHE) had a higher optimum tyre pressure range, and the ideal pressures were different for each class of car. For example, with the older tyre model, the GT4 cars had a lower tyre pressure window than the GT3 cars.

Optimum wet tyre pressure window

In wet conditions, the tyre pressures will need to be adjusted as your tyres will cool much faster due to the cold water. This requires higher tyre pressures as the cold track and air temperatures will result in lower pressures.

Understanding the optimum tyre pressure values

One of the most important things when setting your tyre pressures, is the optimum tyre pressures come after a few laps on track. You should not set your tyre pressures to the values recommended above in the pits.

When setting up your car for a practice, quali or race session, you will always need to set lower tyre pressures in the garage. You should be aiming for your tyres to be in the optimal pressure range after completing a few laps on track.

This is due to the tyres heating up as you spend more time on the track. In the garage, your tyres are colder, resulting in lower pressures. After 5 or 10 minutes on track, your tyres will have heated up, increasing the tyre pressures.

How long do tyres take to warm up in ACC?

Learning to set the correct tyre pressures in the garage, with the aim of hitting the optimal tyre pressure window after a few laps on track is a good skill to learn. It often comes down to experience and a little trial and error, although tyre pressure calculators do exist for ACC.

All cars in ACC will have a slightly different tyre warmup duration, with most cars getting into the optimal range within a few laps of leaving the pits. There area few key factors that affect how fast your tyres warm up in ACC, including weather conditions, car setup and your style of driving.

The key rules for tyre temperatures in ACC

• GT3 cars warm their tyres faster than GT4: In ACC, the GT3 cars have access to tyre warmers which results in the tyres being a higher temperature when leaving the pits compared to GT4 or TCX cars. This means that a GT3 car can set their tyre pressures slightly higher in the garage compared to other classes as they’ll be closer to racing temperature right away.
• Keep all tyres within the perfect tyre temperature window of 80-90°C: The working temperature range for tyres in ACC in the dry is between 70-100°C, with optimal grip between 80-90°C. Aim to keep your tyres in this temperature range at all times while on track.
• Aim for less that 15°C difference between inside and outside of the tyre: Maintaining a consistent temperature across the whole tyre in ACC is important to maximising tyre performance. This can be affected by adjusting your suspension setup with your camber and toe setup having the biggest impact. Ensuring the whole tyre is within a close temperature range will provide maximum longevity for the tyre.
• Adjust tyre pressures by +/- 0.1 psi per 1°C of ambient temperature change: As a rule of thumb, adjusting the tyre pressures up or down by 0.1 psi per 1°C of ambient temperature change will get you into the right working window. Lower your tyre pressures if the ambient temperature goes up. Increase your tyre pressures if the temperature goes down.

What factors affect tyre pressures in ACC?

There are a variety of different factors that will affect your tyre pressures. Accounting for all of these different elements will provide you with information on how to correctly adjust your tyre pressures to get them into the right working range.

Tyre temperature

One of the biggest impacts is the direct relation between tyre temperature and tyre pressures. The hotter your tyres get, the higher your tyre pressures increase.

This means that cold tyres will be at a lower pressure compared to warm tyres. If you overheat your tyres, this can result in you losing grip as your tyres exceed the correct pressure window. As you set your tyre pressures during a practice session, always pay attention to your temperatures while on track.

Track temperature

One of the biggest things that affects tyre temperatures in ACC is the track temperature. A hotter track in the middle of the day will result in higher tyre temperatures compared to a cooler track at night. This may result in you having to lower your tyre pressures during hotter conditions to get back into the optimal tyre pressure range.

Air temperature

The air temperature also has an affect on your tyre pressures in the same way as the track. Hotter weather conditions will result in hotter tyres, leading to increased pressures. As a rule of thumb, use our guide of lowering your tyre pressures by 1 PSI if the ambient air temperature increases by 1°C. Or increase your pressures by 1 PSI if the air temperature drops by 1°C.

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Weather conditions

One of the major variables which affects your tyre temperatures is the weather conditions. In dry conditions your tyres will be much warmer than in the rain, due to the cold water cooling your tyres down. During wet races or mixed conditions, you’ll almost always require higher tyre pressures to keep your tyres hotter with the wet track and cold rain constantly lowering the temps.

Time of day

The time of day will also affect your tyre temperatures with colder night races resulting in lower tyre pressures. During a completely dry race, the air and track temperatures will be much lower when the sun sets compared to midday.

If you are endurance racing, this time factor is something you really need to be conscious of. You will find that you will have to increase your tyre pressures as night arrives and decrease them as the sun rises in the morning.

Brake temperature

Your brakes are one of the closest parts of your car to your tyres. This means that hot brakes can cause some ambient heat to spread to your tyres. You can adjust your brake duct setup to change how hot or cold your brakes are, which in turn can have a small impact on your tyre temperatures and pressures.

Use the in-game ACC tyre temperature widget

Your HUD in Assetto Corsa Competizione has a range of information, including a tyre temperature widget. This is very helpful when setting your tyre pressures, as it shows you the current temperature of each tyre on the inside, center, and outside along with your current tyre pressure.

This widget changes colour based on the temperature;

• Green shows the tyre is in the optimal temperature window.
• Blue shows the tyre is too cold.
• Orange and red show the tyre is overheating.

How tyre pressures affect your car setup in ACC

Not only are tyre pressures crucial for maximising your grip and tyre life. They also affect your whole car setup. With this in mind, you can adjust your tyre pressures to introduce or remove certain characteristics that your car displays.

Understanding how your tyre pressures affect your car setup in Assetto Corsa Competizione allows you to set up your car with certain characteristics. Your tyres are the one area of your car that touches the surface of the track, and how much of your tyre is touching the surface dictates how much grip you have.

Over-inflated tyres – Higher tyre pressure (PSI)

Over-inflating reduces the contact patch between your tyres and the track surface and makes your tyres much stiffer. The perks of this can be that your car is more responsive with higher tyre pressures.

• Tyre feels stiffer
• Less dampening over bumps and kerbs
• Less rolling resistance
• More responsive under the right circumstances

Under-inflated tyres – Lower tyre pressure (PSI)

Under-inflating your tyre will mean that more of your tyre’s surface is in contact with the race track. This is ideal for slower tracks, or for improving rear traction. Running lower tyre pressures also softens your tyre, giving your car more bounce. Very similar to softening your springs and dampers.

• Car is softer over bumps
• More dampening, meaning more bounce
• Increased rolling resistance, meaning more drag
• Reduced tyre life
• Reduced ultimate grip

What we as sim racers want to achieve is that perfect balance between too soft and too stiff. Getting just the right amount of contact patch giving just the right amount of grip and tyre life. So let’s look at the setup characteristics of an under-inflated and over-inflated tyre.

How to correctly setup or adjust your tyre pressures in ACC

Now, I want to show you my process for setting the correct tyre pressures in any situation. I use this exact process during most race weekends, leading to optimal tyre pressures for qualifying and the race. This process allows you to quickly set the correct tyre pressures in a few easy-to-follow steps.

ACC Tyre pressure calculator

For sim racers who don’t fancy manually adjusting their tyre pressures, there are a couple of options. You can download one of our ACC car setup bundles which come with optimal tyre pressures already set. Or you can use an ACC tyre pressure calculator.

While the rule of thumb of adjusting your tyres by +/- 0.1 psi per 1°C of ambient temperature change is a good rule to use if the ambient temperature changes in between sessions. A tyre pressure calculator can take away this guess work.

Our recommended calculator for automatically adjusting your tyre pressures is called the ACC setup tyre pressure adjuster and is available on RaceDepartment.

This calculator is a simple tool which you can load your car setup into and it will create a new car setup with the new ideal tyre pressures. To use this calculator, follow these steps;

1. Load your car setup by selecting the “browse” option: Find your setup on your PC and load it into the calculator.
2. Enter the ambient temperature that was used when the setup was created: For example, if the car setup was created at 20°C, but your race is has an ambient temperature of 17°C, enter 20°C.
3. Set a PSI adjustment and temperature step: This tells the tool how much to adjust the PSI for each tyre and what the new temperature is. For example, if the temperature has fallen from 20°C to 17°C, you would enter 3°C into the temperature step box.
4. Enter the number of setups you wish created: Setting this to 2 will create 4 new car setups, 2 colder and 2 hotter with adjusted tyre pressures.
5. Click “Adjust PSI” to create the new setups: The tool will automatically create the new car setup files and put them into your setup folder, letting you select them right away from the car setup screen in the garage of Assetto Corsa Competizione.

Get the perfect ACC car setups

All of our ACC car setups come with optimised tyre pressures, meaning you don’t need to worry about large tyre pressure changes. Our setup bundles include both dry and wet car setups, both with adjusted tyre pressures perfect for jumping straight into a race.

View all ACC car setups

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Article written by Rich

Founder of SimRacingSetups.com

Rich is the founder, F1 car setup creator and content writer for SimRacingSetups. With over a decade of experience as a graphic designer, marketing director, competitive sim racer and avid motorsport fan, Rich founded SimRacingSetup.com to share his passion and knowledge of sim racing and Formula 1 with other sim racers. Regularly writes for sim racing website SimRaceReviews.com

View all articles written by Rich