01 - Tire Pressure - Suspension Tuning in Forza Motorsport

Описание: Keys to Speed presents a multi-part series on how to tune in Forza Motorsport and Horizon. For more tuning guide details visit: https://forzatune.com/guide/the-fully...

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Transcript

Let’s start with tire pressure, as this is the only part of the car that can be tuned without making any upgrades.

As you drive, friction between your tires and the track will cause your tires to heat up.

As the tire compound heats up, it becomes softer and more pliable, helping it to mould into small cracks in the track's surface, therefore increasing potential grip. This could lead us to believe that hotter is better, but it isn't!

As the tire gets hot (which is something we want), the air inside the tire begins to expand. This causes the pressure inside the tire to rise.

If the pressure rises excessively, the tire may 'balloon' (which is something we don't want). Ballooning is when the edges of the tire lift off the ground, significantly reducing the contact patch, and available grip!

Tires need pressures that suit a maximum contact patch, along with temperatures that suit the compound.

In most cases, 'road' or street compound tires reach their optimum grip somewhere between 140-170 degrees Fahrenheit or 60-75 degrees Celsius.

Sport compound tires will perform best between 160 - 200 degrees Fahrenheit or roughly 70 to 95 degrees Celsius...

While race compound tires can run much hotter, often performing best between 170 - 220 degrees Fahrenheit or 75 to 105 degrees Celsius.

Remember: Tires will not be at these optimum temperatures straight from the pits!

Run a few corners (or maybe even an entire lap) to bring the tires up to race temperature before you start making any adjustments.

Once race temperatures are achieved, re-check tire pressures to ensure they have not climbed too high! Race temperature tires should ideally have pressures between 32-33 PSI or 2.20-2.27 BAR. This will result in a good shape, and the largest contact patch.

You can check tire information by using the in-game telemetry.

While on the track, press 'up' on the d-pad on your xbox controller, and then, using the 'right' d-pad button, scroll across to the 'Heat' page.

Here you can see the temperature of the tires. They are divided into 3 areas for each tire: Inside, Middle, and Outer.

If the centre of the tire is hotter than the edges, then the pressure is set too high - The tire is ballooning!

If the edges are hotter than the centre, the pressure is set too low.

Adjusting tire pressures can also affect the response of the car. Increasing tire pressure increases response, while decreasing pressure reduces response.

Personally however, I recommend you focus on contact patch and temperatures when adjusting tire pressures, and use suspension adjustments to control response. This is covered later in the course.

Should the inside edges of the tire remain hotter than the outside edges (or vice-versa), this is not a pressure issue. This is a camber problem, which we discuss in the next section.

Here is a quick summary of the tuning process:

We start with a “cold” tire pressure in the high 20 PSI range - say 28 PSI, then we drive a bit to get tires up to temperature.

We use telemetry to see if we are close to our target pressure of 32-33 PSI and then double-check the center temperatures which shouldn’t be too high or low relative to the edges.

If necessary we adjust pressure higher or lower and retest, and then we know we will have a good contact patch.