Mental Transparency at 239 mph

At around the 48-min mark of this YouTube video (linked below), they talk about the difference it makes to have your helmet stabilized in the cockpit. Dealing with pure g's without your brain getting rattled allows you to focus like a laser on the pure sensation without any distractions.

Steering wheels are the same way.

If your HMI (human-machine interface) is a shock-absorbing, relatively low-durometer material (think cork/leather/synthetic wraps), you introduce a degree of freedom between your input and feeling the car's response...it's just too "squishy" to be responsive. No matter how tight you wrap it, it'll move...often times during the race.

By properly designing surfaces normal, or perpendicular, to the direction of the action, you CAN increase durometer since you're spreading forces more evenly across a larger surface area. This increase in durometer translates to a more direct connection in the feel for steering resistance...which is directly proportional to traction and peaks as a function of steering angle and load.

So, with a stiffer Shore-A 78-80 material, the goal becomes building surfaces that you can push against. Since everyone's anatomy is unique, you design for tasks first, and not necessarily the individual's anatomy.

This is how team steering wheels are designed in endurance racing. Usually, the driver with the smallest hands determines the grip's depth, and the driver with the largest hands sets the finger spacing. If the disparity between driver anatomical extremes is too great, designs must "soften" peaks/valleys in areas in direct contact with the hand parallel to the line of grip force -- not the task force. Design elements that surround the hand are primarily for task force, and can remain large and more pronounced.

If the design can be dedicated to an individual driver, factors ranging from finger length to forearm strength mean every grip design becomes unique...you simply experiment until you find a design that works for that particular individual's steering method.

Often, a secret to a good design lies in how you accommodate hand movement as you migrate from one hand position to another...even if it's just micro-adjusting to get a fold out from under your palm while going down a straight.

If you notice something about the grip when driving, you can pull out the heat gun and change it if you're using composite thermoplastics....you can keep experimenting.

Air-steering a wheel while watching a race on TV/monitor often reveals ways to change the surface to fix an issue you noticed out on the track.

The goal is total Mental Transparency. If you feel a design element when driving, it needs to be changed.

Sometimes you just need to dimple the material in a certain area to remove a pressure point or accommodate a glove seam. Other times, it's filleting off a chunk on the backside that bothers your thumbnail at around 150-degrees of steering lock. Maybe it's changing the surface texture from a burnished surface to a textured one to increase mechanical grip in hot venues when gloves get moist from excessive sweat.

For most of the races during the '93 IndyCar season, 1"-wide strips were plastic welded on generically sanded underlistings...the design journey was just at its infancy.

By Long Beach '94, a new 4"-wide material greatly simplified installation, and opened up design freedom. 

Jacques Villeneuve's Ser.#062 was the initial hybrid design that incorporated BOTH the 1" and 4" materials. He didn't want to lose the feel of the 1" strips...a slightly lower durometer at the time.

Jacques pushed design limits. Rarely did he NOT remold his wheel at least once each race weekend. We brainstormed non-stop. Fernando Alonso acted similarly, and we spent 2+ days designing Ser.#s 415/415 at Indy 2019.

This analysis illustrates how complicated a Rabbit Hole journey can get...very quickly. 

The key is to design shapes that allow you to relax your grip and still maintain control...which are NOT mutually exclusive if you're using the leverage paradigm for force conveyance. 

Composite thermoplastics let you design and RE-design the human-machine interface over, and over, and over...

But, when you get a design that just "clicks" with your driving style on a given day, the Mental Transparency can have you not believe what your hands are telling you.

After turning in, nudging it back-and-forth ever so slightly keeps it on the peak which seems to light up like a neon sign in the mind. After experimenting with timing/application of footwork in connection with the feel in your hands, things "click", and it becomes a 4-wheeled musical instrument with the hands/feet just moving -- seemingly on their own -- and the car just does what you're thinking.

PERSONAL NOTE: Two years ago, I had Beck Lister Corvette #007 Lightweight out on Ortega Hwy in Southern California with a fast group, and things just clicked. Two weeks earlier, both grips on its 320mm Personal wheel got heavily winged out over a period of 3 nights. I was able to dive into canyon bowls, and carve effortless 4-wheel drifts through whatever apex I wanted. Trailbraking to the apex and finishing off with power right to the edge of pavement was confident and intuitive. I actually began wondering why everyone else was going so slowly.

After we parked, a friend came running up yelling "I've NEVER seen a car jump off corners like that before!"...so it's not just in the imagination. Drive safely.

https://youtu.be/I9TEbM3vkfw?t=47m51s