How Power Steering Ruins Feel & Feedback in Racing
Power steering is often used at a last resort by race engineers to keep the driver from complaining. However, the slow-twitch muscles at the outer extremeties have less ability to relay to the brain the resistance they sense when compared to using them in concert with the fast-twitch muscles operating in their sweetspot.
If the car is fully sorted, and you're relying primarily on friction between the gloved hand and the wheel for force conveyance (i.e., old friction paradigm), then resorting to power steering is your only choice after you've already optimized the coefficient of friction at the human-machine interface and the driver complaints continue as a result of exceeding his/her fatigue resistance threshold.
However, if a driver can incorporate the larger fast-twitch muscles located closer to the body's core and keep them operating at their sweetspot, the brain has greater resolution in reading the steering resistance feedback signal. This incorporates the brain's cerebellum as well as the anterior intraparietal lobe, and suddenly the limit seems to light up like a neon sign in the driver's mind.
Designing steering wheel grips to account for the lower steering resistance of power steering means taking advantage of the extra sensitivity that lies between the fingers. Since callouses are normaly not present in this area and the nerve area density is higher as well, improperly designed steering wheel grips have a pronounced negative effect.
By the same token, PROPERLY designed steering wheel grips in this area can have a profound effect for enhancing steering feel. Therefore, extra care needs to be taken when designing steering wheels grips in this area for power steering systems.
Since the touch is so light, ingress/egress ramps to and from the wheel require careful consideration, as well.
Ideally, the best solution is to discard the power steering system entirely, and use a properly designed custom-molded steering wheel that incorporates both sets of muscles operating at their sweetspots.
Since EMG tests revealed that a 54% reduction in grip effort occurs when using properly molded steering wheel grips, race engineers need to start thinking outside the box, and adopt a new philosophy that starts here:
"TELL ME WHAT I NEED TO KNOW THAT I DON'T EVEN KNOW TO ASK RIGHT NOW".
Welcome to the new leverage paradigm, team: fewer driver complaints, better more-accurate driver feedback during debrief, lighter car, fewer parts, greater underhood accessibility, lower lap times, fewer crashes, and cheaper overall operating costs...when the grips are molded PROPERLY.