Sebring toughest corners
Throughout the 2009 American Le Mans Series season, SPEED broadcaster and former standout road racer Brian Till will share his insight on some of the most critical corners and sections of Series venues. He starts with Sebring International Raceway - all 3.7 miles and 17 turns - as a prelude to Saturday’s 57th Mobil 1 Twelve Hours of Sebring presented by Fresh from Florida.
To compete in the Mobil 1 Twelve Hours of Sebring is to attempt to claim your place on the honor roll of sports car drivers who have triumphed over not only the other competitors, but over the harsh conditions that this circuit dishes out. Some say that Sebring is the perfect test for the 24 Hours of Le Mans, the French endurance classic. And in fact, the last 10 winners at La Sarthe have competed at Sebring prior to their French triumph. This year will mark the 57th time that drivers will race “once around the clock” to claim the honors in what will be a very special event: the 100th American Le Mans Series race.
But many drivers and team managers will tell you that to win at Sebring is more physically, psychologically and emotionally draining than winning at Le Mans. You might wonder how that could possibly be. But the answer is in the nature of the track.
Sebring is not a long circuit compared with Le Mans. In its present configuration it measures 3.7 miles in length with 17 corners. But it is the combination of those corners, the changes in track surface, the sandy soil that blows across the racing line and the brutal and harsh bumps of its concrete runways that will literally shake a car, driver and team apart throughout 12 grueling hours of competition. With multiple classes of competition, the challenges of the circuit become even more exaggerated.
Start with the bumps. Remember that the Sebring circuit started life as a World War II bomber training base for B-17s. The runways are made of concrete poured in giant squares, some estimated to be at least six feet thick. The number of these squares and the sandy sub-soils that they rest upon coupled with the years that they have been in place mean that some have shifted ever so slightly, creating some incredibly harsh bumps. Keep in mind that the concrete was laid down to create a flat surface for period bombers to land on with soft tires and generous suspension travel. The engineers who created the runways never envisioned today’s engineering marvels such as Le Mans prototypes traveling the same routes as the Memphis Belle.
The runway surface is utilized from Turn 15, down the Ulmann Straight (sometimes called the back straight), through Turn 17, down the front straight and through most of Turn 1. It is Turn 17 and Turn 1 that present the harshest challenges.
In Turn 17, just under the paddock’s drive-over bridge near the apex, there is a bump created by the runway’s surface that is so harsh that it will sometimes pitch a car completely off the ground. Even prototypes with their aerodynamic advantages and high-tech suspension systems have a difficult time getting the tires to follow smoothly over the pavement changes. The ability to get through this corner cleanly, on line and unaffected by the bumps is critical. The turn is long, fast and rough. Prototype drivers can sometimes utilize two different lines in order to get around slower GT traffic but expect to see GT cars with only one way through. As if the corner wasn’t difficult enough I should also mention that heading into the braking zone late in the afternoon, the driver is facing directly into the setting sun. Now you have all of the aforementioned challenges, only you can’t see them on the way in!
In Turn 1 the challenges come in several forms. To begin with, the corner is the fastest on the circuit and the driver can only see through the first half of the corner from entry. In 2008, several of the LMP2 cars were able to get through the corner flat out in qualifying trim. But to carry speed through Turn 1 things must be in order. If you’re driving a prototype your vision is well ahead of the car scanning for any traffic that you will be able to clear before turn-in as well as - and perhaps more importantly - any traffic that you won’t be able to clear before turn-in. The entry is incredibly quick, even if you take off a small amount of speed. As you roll back into the throttle there is a significant bump about halfway to the apex or the inside clipping point of the corner and another significant bump about 2/3 of the way through the corner, near the exit. Having a suspension that will handle these severe bumps during high-speed/high-load cornering is absolutely critical to getting through this corner in good fashion.
I said earlier that the runway surface creates most of Turn 1. To add yet another challenge to the corner, the surface transitions from concrete to asphalt at the corner’s track out and also narrows considerably.
Not only does a chassis have to work well through these bumpy portions of the race track in order to gain outright speed but all of the car’s components must stand up to the punishment. Suspension pieces, mounting brackets, switches, fragile electronic components and more must all be cushioned and protected from the jarring nature of the track. Merely completing 12 straight hours at Sebring is an accomplishment, but doing so ahead of the rest of the pack is what champions are made of.
After Turn 1 the challenges of the circuit come in several forms. Turns 2, 3, 4 and 5 are patience corners and momentum corners. Prototypes will look to get past slower GT traffic under braking into Turn 3, but a clean pass here really comes down to both drivers. The prototype car wants through and has the braking and cornering to do it, but the GT car may be in a fight of his own and wants to lose as little time as possible. Working together here gets the job done cleanly but fighting too hard and risking too much often leads to heartbreak.
Exiting Turn 5 and running through Gurney Bend is always exhilarating. One of the better passing zones class-on-class or class-vs.-class is at the Hairpin (Turn 7). In recent years the straight was shortened somewhat to allow for greater runoff for safety reasons and the resulting corner is a bit quicker than the original. It is still one of the slowest corners on track and any time you have an area where cars are trying to out-brake the competition you are sure to see action. The entry here is very flat which means it can be difficult to see good reference marks from the cockpit. This is another one of those corners where late-race desperation can throw the whole game away.
On through Turns 8 and 9 (known as the Fangio Chicane) drivers are looking to capitalize on their good exit out of the Hairpin. Heavy braking into Turn 10 provides another good overtaking spot. And throughout this “infield” portion of the course (Turns 3 through Turns 13) the track will get very dirty throughout the race. From drivers dropping wheels off in the apexes to spins that take a car off course and then back on, the fine sandy soil of the Sebring area always seems to find its way on to the racing surface in this area of the track. In dry form, the sand is almost like talc on a shuffleboard table and the cars will slide across it just like a shuffleboard puck. In times of rain the sand will bond together and be thrown into the radiators of trailing cars leading to potential overheating issues. Rain or shine, more than once this sand has affected the outcome of the event.
From Turn 13 through Turn 16 (on to the Ulmann Straight) is very flowing, momentum portion of the track. Turn 14, also known as Bishop Bend is incredibly quick in each of the four classes of American Le Mans Series competition. Coming into Turn 15 the drivers are back on the brake pedal and trying to carve a good line and keep momentum up for a good run down the following straight. Traffic in the Turn 15/16 area between classes can lead to frustration and hard feelings. As a GT driver, you are trying to get through this area losing as little time as possible and maximizing the line that you need to do so. As a prototype driver you want those pesky GT cars out of the way.
Fortunately a mistake here doesn’t need to result in anything more than frustration as the cars have entered back onto the runway section of the circuit. It is much better to take your car “outside the lines” here and avoid contact than fight for a spot that will only take you out of the race.
As mentioned earlier, Sebring International Raceway is demanding and very physical in its nature and is a true test of man and machine. It is the personality of the track that makes the Mobil 1 Twelve Hours of Sebring such a special race; that coupled with the personalities of the team owners, drivers and crews who choose to do battle here year after year.