Performance cars can experience tire skipping at full lock due to the Ackerman effect and steering/suspension geometry, which causes the inner and outer front tires to trace different arcs at full lock, resulting in one tire fighting for grip and scrubbing or "crabbing" along the road. This is a normal side effect of a suspension and steering design optimized for high-speed cornering, not slow-speed maneuvering.
The Ackerman Effect and Steering Geometry
- Different Arc Lengths:
When you turn the steering wheel, the inner and outer front tires do not turn at the same angle. The inner tire turns at a sharper angle than the outer tire.
- Tire Scrubbing:
At full lock, the difference in the arcs the tires need to trace becomes more pronounced. This "discrepancy" causes one tire (often the inside one) to scrub or drag on the road as it tries to maintain the required turning radius while also moving forward.
- Optimized for Performance:
This geometry is essential for optimizing the slip angle and grip of the tires when cornering at higher speeds, even though it creates a noticeable judder at low speeds and full lock.
Why Performance Cars Are More Susceptible
- High-Performance Tuning:
Performance cars are designed to have aggressive steering geometry for optimal road grip and handling at speed, making the Ackerman effect more prominent at low speeds.
- Tire Characteristics:
The use of performance-oriented tires, which are often stiffer, can make the skipping sensation more noticeable, especially when cold.
When It's a Concern
- Not a "Problem":
Tire skipping is a normal function of the car's design and not a defect or malfunction.
- Factors Affecting Severity:
The effect can be more pronounced in:
- Cold Weather: Tires are less elastic in the cold, making the scrubbing more noticeable.
- Low Tire Pressure: Incorrect tire pressure can exacerbate the issue.
- Tire Wear: Worn tires can also increase the severity of the skip
In short, it's not a problem, it's a trade off. Just like a stiff ride, often found in high performance cars, excellent on high speed cornering but sucks on your daily commute. Or a rough idle, when running aggressive cams, large injectors, both designed to provide high rpm power, not daily comfort.
Yes, some may argue that it's still a practical, daily car, not a track day weapon. I get it, and you do have a point, but it is what it is. It IS a practical car, but it also shares a lot of characteristics with high performance cars that aren't intended to be practical.
One last note, some types of tires may reduce the effect. Mine does it too, and I'm going to see if it becomes less pronounced with my new A052 semi slicks, which I plan to order soon. There's a good chance their bulgier design (the exact opposite of tire stretch), making them a whooping half an inch wider than the PS4S, on the same 245 section, helps with providing better traction at full lock turns even when cold. Not that I give a crap to be honest, as I came to terms with all these little trade offs very quickly. The car delivers just where I want it and that's all that matters.
