Setting up your car for a wet race is different to your dry weather setup. However, you’ll still be setting up the car with two aspects firmly in mind: do you want a ‘safer’ setup that is tuned to minimise oversteer but maximise stability, predictability? Or do you have a lot of faith in your wet-weather skills and therefore want to lean toward a faster setup that is more prone to oversteer on turn-in and will require that you’re on it all through a lap?

There is, of course, a third possibility―one that combines these two extremes.

When you begin to tune for wet weather, a good starting point is the tyres.


― Ensure that you have the wet tyres selected/fitted to the car for wet conditions. It may sound simple, but even real-world teams sometime get caught out in the heat of action. Either use the ‘Automatic By Weather’ tyre option, or select the wet tyre itself for race cars. For road and track cars, there are various different tyre options, each with various different amounts of tyre grooving suited to wetter conditions, some possibly resembling intermediate tyres. There are no intermediate tyres for race cars.

― Aim for similar tyre pressures to what you would use in the dry. Guide on target pressures can be found here:

― It can be beneficial to run tyre pressures at around 0.02-0.05 bar lower than you would in the dry, just to increase the contact patch between the tyre and track surface for better stability and grip. Naturally this will lower your top speed, but in the rain, this is not of critical importance.


― Lowering the Brake Pressure is important. Less grip means it is easier to lock the tyres under braking, and locked tyres in the wet is a fast route to a big off. Lowering the Brake Pressure counters this, but you still want to ensure you get good stopping power―do that by braking correctly or, in other words, to just under the point of ABS kicking in, or the tyres locking.

―Adjust the Brake Balance for your personal preference. This is one of the elements that really affects how your car handles in the wet (and dry) and can help tune toward the two setups discussed earlier. Having it further forward means front brakes do more work, which generally translates to a safer ride as it will produce understeer if the brakes lock up. Going backward with the balance will loosen the car and helps rotate the car slightly into the corner, but adjust this in moderation as you don’t want to lock the rear brakes and oversteer in an unpredictable manner in the wet, or to the point where you’re having to fight the car into the corner.

―Reduce Brake Duct Openings (Front and Rear). The lower Brake Pressure, and less grip from the wet surface, will result in less heat going through the pads and discs. You therefore don’t generate as much heat and may fall outside of the brakes’ optimum ranges. Close the brake ducts up to keep them within their optimum window for better braking performance, but also to get the added benefit of less drag and better straight-line speed. This will be circuit- and also temperature- and conditions-dependent.


― Generally speaking, aerodynamics aren’t as effective in the wet as it is in the dry. Depending on the track, putting on more aero to compensate for this lack of grip could be more detrimental to lap times because the drag will slow you down while the increased aero won’t be that effective through corners where speeds are now lowered due to the wet conditions.

― Ensure you maintain aero balance (depending on the setup type you’re after). More on the rear and less on the front will be safer by creating a more understeering balance. Taking off downforce from the rear can induce more oversteer but be faster on the straights.

― For low downforce tracks, you can still run low downforce setups, just add a click or two of rear downforce for slightly better rear stability.


― Reduce the Camber Angles from what you would usually run in the dry. You won’t have as much grip or produce the same downforce, though, so focus on maximising the contact patch as much as possible. The lower camber angles will also provide better braking power as well as traction when accelerating in a straight line. The car will be also more progressive when sliding, making it easier to catch when running lower camber angles, with higher angles resulting in a more snappy and harder to catch slide when exceeding the limit.

―Soften Spring Stiffness & Anti-Roll Bars to lean more towards mechanical grip. Do so in moderation though to ensure the car still feels supported going through the corners, and if driving a high downforce car, ensuring you still use the downforce and don’t sacrifice too much in the pursuit of mechanical grip.

― Steering Ratio can be adjusted to personal preference. But it should be noted that running a higher ratio with a heavier feeling may allow you to be more precise with steering inputs, especially in moments where the car is trying to break away from you.

― Toe-In Angles should be increased slightly. Whichever direction you go, more positive Toe-In will result in better straight-line stability, while more negative Toe-In results in better steering response: adding more angle helps to produce and hold more tyre heat.


― Bump Stops should be adjusted the same way you adjust them in the dry.

― Various Damper options should be adjusted to match changes you make to the suspension using Jussi’s suspension calculator:

― Further Damper adjustment can be made for further fine-tuning in response to bumps, curbs and driver input to try and maximise the car’s stability.


― Fuel, Boost Pressure and Air Restrictor principles are the same in the wet as they are in the dry. Make sure you have enough fuel to go the distance you require for your session/stint/race. Maximise Boost pressure for best acceleration and top speed, but lowering it can be beneficial in older cars as this not only reduces engine wear, but also reduces the amount of wheelspin you’ll get when the turbo kicks in. Leave the Air Restrictor at its maximum value.

―Radiator Opening can be lowered to improve straight-line speed, but make sure to leave it open enough to allow for sufficient cooling to the engine. The amount of adjustment depends entirely on the conditions and temperatures.

― Engine Braking should have its value increased (reduces engine braking effect) to make the car safer, and less prone to breaking free when shifting down the gears at low speed. Running a more aggressive (lower value) can help to give the small amount of rotation desired upon turn-in, but use this moderation in the wet.

― Gearing should be adjusted where possible to ensure that you aren’t in-between gears going through corners and are nearing the rev’ limiter on the longest straight―leave yourself some headroom for slipstreaming and passing other cars.

― Traction Control and ABS Slip should be adjusted to your own personal preference. These are when the systems kick in, and with the reduced grip in the wet, they will kick in a lot more often. You will usually run a lower TC Slip value in the wet compared to the dry, and you might also consider a higher value on the ABS setting for wet conditions.


― More stable and gentle values are beneficial for the Pre-load and Number of Clutches to reduce the chance of the tyres losing grip when transitioning from on-throttle to off-throttle, or off-throttle to on-throttle.

― Adjust the Coast and Power Ramp values depending on the desired amount of locking you want, and which wheels are spinning up. Try to reduce the amount of wheelspin from a particular tyre and spread it between the two with the Power Ramp angle in the wet as this will afford a more predictable car on exit. The Coast Ramps can be adjusted for better braking stability or cornering.

Final thoughts

Most importantly, be smooth, progressive and measured with your inputs in wet conditions. Although setups help, a lot of driver ability comes into play driving in the wet with regards to your lines, reading the track and other drivers, and maintaining control of the car. Although you can go for a faster setup over one or two laps, having a stable and consistent setup could a better strategy for longer races.

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