The edge of adhesion in a racecar, “the limit” is hard to define and easy to misjudge. Unless we’re hypersensitive creatures who can determine the exact grip available, we’ll have to make clumsy stabs at finding it before our senses are properly calibrated. For 98 percent of performance drivers and racers out there, this is unavoidable.
The basic takeaway for the aspiring driver is this: it pays to put the bit between your teeth and go for it. There are numerous instances in which the assertive approach will pay dividends, even if the driver is a little on the overzealous side.
For instance, race starts favor the intrepid driver. While the pack is waiting for their tires to come up to temperature, a coordinated starter can push a little harder, sensing just how much grip he has and respond when he overshoots the mark. This driver should have little difficulty breaking away from the pack. Also, if a driver has just had a lousy qualifying session, this skill can help him find a few grid positions as the others flounder around on cold rubber.
Hopefully, this approach should help him make the most of limited track time. In qualifying, or in Time Trial, the driver has limited time to get the most out of his tires. To complicate matters, the window of optimal performance is limited not just by the stopwatch, the machinery, and the cramped schedule, but the elements as well.
“In time attack, you’ve only got a couple laps before the tires fall off or the engine blows up,” says Billy Johnson, a Ford factory driver with experience in NASA, WEC, NASCAR, and IMSA. True, time attack machinery is temperamental, but even if it runs reliably, the fact is that there are only a few opportunities to find a fast lap. The fastest laps are usually set in the morning when the ambient temperature is relatively cool.
There are also unforeseen issues to consider. If a driver assumes he’ll have the full 30-minute practice session to get into his stride comfortably, he’ll have nothing to respond with when the practice session is cut short for whatever reason.
In short: the driver who waits for the planets to align is bound to be disappointed. With the aid of three professionals with methodical approaches, we’ve outlined a few practical steps any driver can take to push hard and make the car come to them. Interestingly enough, testicular fortitude or a lack thereof do not play a role here.
A Bit Timid
An inexperienced driver will only have a hazy picture of how much grip there is based on the information coming through the wheel, the seat, and the pedals. He needs to proceed cautiously at first and remember that the aim is to build a foundation he can later use to assess his driving.
A little emphasis on remaining cognizant yields a little detail for that picture, even if he is not pushing the tires past the limit of adhesion. “Car control is less about reacting than it is anticipating. Seat time will help a driver predict the car’s behavior so that he’s not constantly reacting to surprises,” says Johnson.
Drivers don’t have to enroll in a car-control course to begin thinking about approaching the limit. “Go by what your ears tell you,” says Nik Romano, NASA and USTCC Champion. “You can usually gauge the car at seven-tenths if the tires are starting to howl. You can approach that point, then back off.”
Moaning rubber is just one source of information a driver needs to attune himself to. If a driver is tense, he will not be as receptive to the various forms of information if he were relaxed. “I try to remind the driver not to grip the steering wheel too tightly. If they can release their grip, they should be able to feel a lot more coming through the wheel. This helps them adjust their inputs accordingly,” says Thomas Merrill, Trans-Am Champion and FIA Silver driver.
“We usually talk about lateral grip when we’re pushing, but we need to try and find the longitudinal limit, too,” Merrill mentions.
Interestingly, the student doesn’t need to slide to get a taste of the limit. The easiest way he can do this is by braking really hard on a straight section, preferably with a little runoff area. “Wait until you have nobody behind you, then, in the middle of a straight, increase your braking pressure to the point of ABS intervention or lockup. Note how the point changes as the tires come up to temperature, and use this information to gauge the amount of longitudinal grip available,” Merrill notes.
Introducing Intermediate to Safe Slip
Up until this point, the driver’s been tasked with sensing he’s nearing the limit and staying safe. However, there comes a point where the driver, no matter how sensitive he may be, will have his development limited by a lack of car control.
Although they might be smooth and precise, their discomfort will prevent them from reaching the limit in a timely fashion. They might be able to take small bites over a long period and get fairly near the limit, but there’s a chance that they’ll scare themselves after putting themselves in a situation they cannot respond to appropriately. This can set them back a long while.
At this stage, some choose to avoid the challenge of pushing altogether and dupe themselves into thinking smooth is always fast. That’s not necessarily the case. Concerning oneself too much with the kindness they’re showing their tires, the temperatures their brakes have to endure, and the general sweetness they’re showing their car can hold them back. This is because mechanically sympathetic driver’s cautious approach can keep them from exploring the limit and adding to their fact-based foundation.
Of course, there’s a point beyond which assertiveness is punished. This is the realm of overdriving, but even the ham-fisted driver who has some comfort with large slip and yaw angles will get a feel for the limit faster than their tentative, technique-obsessed counterpart. They can use these experiences beyond the limit to glean new information to add to their database.
Because practice is needed to build a slide-saving repertoire, easy repeatability is important at this point. “I suggest my drivers (in RWD cars) find a slow corner with a hard acceleration moment. “It simplifies the process when they can get on-demand oversteer with the throttle pedal,” Merrill recommends.
But brief, one-and-done power-oversteer is not the only type of slide a driver needs to accustom themselves to. To help practice the subtler, longer, and more complicated slides that happen at higher speeds they should use longer, medium-speed corners with runoff area to practice. These corners give the driver lots of time and space to react and try new things. Several examples include:
- Turn 11 at Thunderhill East
- Turn 7 at Sonoma
- Turns 2 and 3 at Barber
- Turn 7 at Sebring
- Turn 7 at Road America
- Oak Tree at VIR
- The Keyhole at Mid-Ohio
- Turn 2 at Willow Springs
The Grand Takeaway
Once the students learn at what point the tires will start to slide and how to correct these slides, they need to make that information and muscle memory parts of a logical process to determine exactly how to drive a particular corner.
For instance, braking at the limit is more than just smashing the pedal and stopping the car quickly. After learning how to lock the brakes with plenty of space before the corner, the student will need to push that point forward somewhat if they’re going to go any faster.
“To figure out where to actually brake, start by braking as hard as the tires will allow, on the verge of lockup or at the point of ABS activation. Pick a spot and use that pressure. If you’re still over-slowing the corner, you have a lot of space left,” says Romano.
“The next lap, move your braking point several feet deeper and brake hard again,” he added. “Keep creeping up on the turn, using that same brake pressure, until you’re almost missing your turn-in point. Then, smoothen the brake release and balance the car toward the apex. Now you know the entry limit!”
The Necessary Mindset
While bravery got them to begin pushing the limit, consistently engaging with it requires the analytical, methodical approach Romano illustrated in the case above. Truly, courage without any objectivity is not, at the end of the day, all that useful. Detaching helps here.
“You need to stop caring and need to remove your emotions and irrational fears. These subjective feelings are holding you back from sensing objective feedback that you need to analyze and respond to. Change your inputs methodically to reach the goal of finding the limit. Improvement or going fast is not about having courage or “balls,” but rather making educated responses to measurable feedback and ignoring any extraneous thoughts. The sensation of speed doesn’t matter, something that seems scary doesn’t matter. Paying attention to what the car is telling you, and responding accordingly to drive at the limit is all that matters,” says Johnson.
There are four stages a driver progresses through in the pursuit of speed. Almost every driver begins by driving raggedly and slowly, then, usually after reading “Speed Secrets” or something similar, they’ll learn enough to smooth their inputs and place their car more appropriately.
Then drivers must take a leap — the time when having some courage and a little car control come in handy. If they’re able to push braking zones reasonably late and get on the throttle earlier, they’ll start to paint a more detailed picture of the limit.
Feeling the car move underneath them, some of these intermediate drivers are convinced they’re extracting all the tire has to offer. They have an incomplete picture of the limit — whether or not they’ve reached it prematurely hasn’t really crossed their mind.
Still, they have to be applauded for driving in this spirited fashion. Even if this driver is overshooting the braking zone and hacking at the wheel, they’ll still be faster than the driver who under-drives smoothly. Their willingness to push the tires past the limit of adhesion serve this driver well. He can adapt to new tracks and conditions fairly quickly.
“Due to their seat time and comfort past the peak lateral load limit and experience with how cars transition into oversteer, it does not take them very long to feel out how a car responds and the severity of inputs needed to make a car rotate or slide,” says Johnson.
The Time to Refine
Of course, too much aggression is not always beneficial. For example, taking this overly aggressive style into a fast corner or with a high-downforce GT or prototype that requires smooth inputs does not yield great results. To get the most out of the car and the tire, the driver will have to exercise some discipline “to reel it back in and drive nearer to the peak of the tire’s friction graph,” adds Johnson.
The objective then, as it has always been, is to adjust inputs to keep the tire within its window of ideal slip and yaw angles — closer to the peak of the friction curve. The difference is now that the driver has surpassed the limit — he no longer has the problem of finding it at all.
To do this, he’ll have to remove as much emotion as possible and remain analytical. While pushing on cold tires requires some bravery, the gifted drivers who are on-pace after a couple laps aren’t relying exclusively on bravery. Their experience has taught them how much grip they ought to have, and their analytical mindset proves exactly how much they actually have.
It’s this combination of experience, technique, and analysis — all glued together with a dose of daring — that allows them to paint a detailed picture of the limit.