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Skip Navigation Links. Despirately Seeking Smoothness:

As Jim Nichols emphasizes in his introductory talk at our track schools, one of the key objectives of the day is to teach students how to be smooth drivers. Unfortunately, smoothness is one of thse things that's hard to describe, but you know it when you see it. Not very helpful for a student new to the game.

At the recent Last Chance driver's school at Lime Rock, I had the opportunity to ride with a variety of students at different levels of skill. I noticed that there were definitive levels of accomplishment between the groups as well as common challenges to making further progress.

In the case of the novice groups, the key focus is on being able to find the line, developing sight pictures, and establishing hand-eye coordination for steering inputs. Their key to moving on is being able to establish consistency in lines and to be able to identify errors such as missing reference points and their effects, i.e. the consequences of being early or late.

The intermediates tend to be quite accurate and consistent with their lines and are able to diagnose their mistakes with respect to line quite well. At this level, the performance was "smooth" at moderate speed. However, as the laps rolled on and speed picked up, "smoothness" tended to head for the exits.

To address this situation, I think it may be more useful to think about "smoothness" in terms of balance. What I am referring to is the balance of the car as we drive around the circuit. Balance in the car is determined by how we weight the contact patches of each tire through the controls, and perhaps, of greater importance, how we transition from one attitude of vehicle dynamics to another.

One of the general principles of driving we all accept, is to maintain the highest possible speed around the circuit. It is reported that one of Fangio's teammates on the Maserati team of the '50s had difficulty qualifying at a circuit he had not driven before and asked the Argentine for advice. Fangio thought deeply for a few moments with brows furrowed struggling for the right words and then said haltingly, "More gas, less brakes."

The conclusion many of us apply to driving is that we must maintain full throttle for as long as possible and leave all our braking to the last possible moment. One of the most critical transitions that can affect performance is the transition from braking to accelerating. The vision most of us have is of hard, late braking before a corner to take off the required speed in the shortest distance. A great example of this is the Long Beach CART (Indy Car) Grand Prix where the cars are wailing down Shoreline Drive at 180 mph and braking violently for a 40 mph corner. This is the image many drivers carry to the track when they think about braking.

Let's think about Lime Rock for a minute. Some professionals refer to it as the "oval road coarse." The reason is that there are no really hard braking zones and if you think about the back part of the circuit (the Uphill, West Bend, and Downhill), these are all high speed turns that require keeping momentum up to lay down a good lap time, similar to a speedway.

What I discovered with some intermediate students as they picked up speed is that they tried to brake later and harder on the entry to these high speed corners. A little review of how a car behaves under braking and acceleration is useful. Figure 1 shows in the first frame the effects of braking: the chassis rotates forward, weight is transferred off the rear to the front tires generating a lot of traction potential, and the front springs are compressed storing a lot of kinetic energy. The second frame shows that under acceleration the energy stored in the fron springs releases and unweights the front, the chassis rotates to the rear, while the front tires unweight and have reduced traction potential. The consequences of braking abruptly, leaping off the brake pedal, and then hard on the gas were to destroy traction available on the front tires, create a push (understeer) to the outside, missing the apex, and preventing further throttle application to the exit of the corner.

A trace of speed versus corner reference points is shown in Figure 2 which compares two techniques for high speed cornering. The solid line represents the late hard braking technique. Here, braking is held as late as possible followed by a hard application. Usually, as is shown here, the application is usually too hard for several reasons: the speed with which the driver tries to apply the brakes compromises pedal control and, visually, it appears that he is in deep and wants to make sure he has slowed to a safe speed to take the corner. Often, the result is to overslow the entry at which point the driver leaps off the brakes and adds a good dose of gas. This causes the front end to unweight, lose traction, and generate a big push under power, and miss the apex. The cure for this problem is to not add any more gas, let the push dissipate and wait it out until he can add more power after the apex to the corner exit.

An alternate approach represented by the dashed line seeks to keep the car as balanced as possible with a minimum of unnecessary shifting in vehicle loading. The technique is to compromise the time at top speed on the straight leading up to the corner by braking early, lightly, and longer. This serves to minimize unwanted weight transfer and manages to maintain a relatively higher overall cornering speed through better balance and an accurate line.

What I felt while riding with students who tried to brake late and hard was a fairly abrupt dip of the nose, a pop up of the nose as the brake was immediately released, and then another pop up as the gas was added. The ideal to strive for is a seamless speed adjustment, just the same as gradually dimming a light and then bringing it back up on a rheostat. There should be no discernible point that one can detect a change from brake to gas. Instead of stomp and steer, the pedals should be squeezed. Squeeze the brake to build braking force, un-squeeze the brake to gradually release them and maintain chassis balance, then gradually squeeze the throttle open to keep the chassis under control. (In many instances, I have my right foot briefly on the brake and gas at the same time as I roll it from one to the other.) When done properly, the technique is very unexciting, undramatic, but devastatingly fast. This is born out by the overall speed advantage shown on the chart.

Remember, the objective is not to go the highest speed possible everywhere around the track (because it's impossible), but to go the highest average speed possible around the circuit. Achieving this objective requires compromises to maintain the best balance in the car. Please don't think you're on the sidelines till springtime to work on your skills as these techniques can easily be practiced in everyday driving. (One drill is to modulate the brakes while coming to a red light or stop sign. Un-squeeze the brakes as you approach the stop to gradually release the front end so that when you come to a full stop, there is no bounce in the hood as the chassis comes off the springs.)

Think smoothness and balance.

Article by Jim C.F. MeVey
Reprinted from Die Zetung (Connecticut Valley Chapter)