Car control

Tire use optimization

Understanding tire usage is crucial for improving pace, consistency, and car setup knowledge. The contact point between the tarmac and the tire is key.

We know tires are used for accelerating, braking, and steering. However, problems arise when we push too hard to go faster. Tires can only handle only so much acceleration, braking, and steering at once.

When slowing down on a straight, it's vital to avoid steering input to maximize braking performance. Similarly, when going through corners at max speed, adding acceleration can overwork the tires, leading to oversteer or understeer, depending on the setup.

Consider this: when you command the rear tires to accelerate, they scrub the surface to transfer horsepower to the tarmac, causing acceleration. In 1st or 2nd gear, traction control might even interfere if the tires spin.

But in 2nd or 3rd gear, a delicate situation arises. With limited downforce and enough horsepower to spin the car, 100% acceleration with steering input can be risky.

As speed increases, acceleration decreases, allowing more steering input since the rear tires aren’t burdened with acceleration as much, and downforce helps grip the tarmac.

At high speeds, imagine a percentage bar from 0-100% tire usage—anything above is overload, meaning a spin or slide.

For example, at 240 km/h, just 1 degree of steering might already push the front outside tire to 95% usage. Turning sharply at high speeds like in a video game isn’t possible think Need for speed

At lower speeds, like 120 km/h, you can use 45-60 degrees of steering and even apply even some braking

Front-engined cars struggle with this the most, like when braking hard at Suzuka Turn 1. Approaching at 260+ km/h, you need to brake hard and then start turning in. The front outside tire is under massive stress, slowing the car and turning it. With a high-level setup, you can use precise inputs to manipulate rotation with trail braking.

However, the front weight still pulls the car into understeer. When you come off the brakes too fast with steering input, the front outside tire, no longer needing to slow the car, suddenly becomes more efficient at steering. This can cause oversteer on corner entry.

To practice, use brake input from 70% to 50% and back to 70% to see how tapping the brakes changes how your car pulls into the corner. Stiffer wheel rates or anti-roll bars can help reduce this oversteer when coming off the brakes.

this forgiveness I also have integrated into the car-level setup packs in the Patreon store.

I'm working on a setup solver for GT3 cars and ACC, aiming to move away from meta tactics and create a consistent tool regardless of game updates. Check out the Patreon for more info.

P.S. I'm integrating this tire philosophy into the setup model. It's messy, but I'll share the progress with Patreon and YouTube members.

cheers,

Arnout