The best drivers always look for the smoothest lines and the shortest possible route through a corner when the grip levels afford it. Not circumnavigating the curbs is something that simply needs to be done to get a competitive lap time, and as cars are much more reliable today than they ever were, eating a little curb won’t necessarily ruin a race. However, there’s a bold distinction between the times when the curbs should and shouldn’t be used. However, it takes a little bit of experimentation to get a feel for that distinction. Hopefully this should help that experimentation go more smoothly and keep your wallet closed.
At times, the curb is your friend. Other times, it certainly isn’t, and flirting too much with it can land you in the hospital. Knowing how much to woo the curbs takes time, technique, and appreciation of the circumstances. Of course, it always pays to find a good chiropractor if the curbs are particularly tall.
Curbs are an intimate part of racing. Inevitably, if you want to be competitive, you can’t avoid them altogether. As always, one should look to minimize the amount of road taken without upsetting the balance of the car much. Learning how to approach curbs depends on the sort of car you’re driving and how it responds to a momentary unsettling of the suspension and platform. If a car is especially dependent on aerodynamic grip, the apex curbs have to be dealt with very carefully, though exit curbs, as long as they’re not too tall, can be run over without any real risk or challenge.
How hard they can be covered is, again, dependent on the car. If hit too hard at high speed, the aerodynamic platform can be disrupted, the grip diminished, and an incident likely. Of course, slower corners – say below eighty miles per hour – are generally less disruptive to the car’s aerodynamic balance, and can be approached with a little more gusto. Perhaps it should be mentioned at this point that curbs near the turn-in point are generally not used, and can unsettle the car while braking. There are examples, however, like Laguna Seca’s Turn 6, which rewards a little of that since it helps turn the car.
One tricky aspect of racing over curbs is that, with enough skill, their upsetting nature can be harnessed to turn the car. This pertains more to cars with relatively soft suspension, so prototypes and formula cars are excluded here. In a GT car, though, it’s not bad if you kiss the curb with the inside tires – the jarring and jostling can help turn the car, and the soft suspension can help soak up some of the violence so that it’s manageable. It will put a little more heat into the tires, too. GT cars are very receptive to that sort of treatment, though, so it seems all the good guys out there know how to hop an apex curb so that they temporarily unload the tires just long enough to help the car turn. It all depends on the angle of attack, though.
Whenever a car gets pivoted onto its side, it tends to stress the outside tires quite strongly, and generally shocks the whole chassis. Some cars, like those mentioned above, are a little better at handling that sort of punishment, but some very stiffly-sprung cars will get upset if they’re not treated with a little respect when nipping at the curbs. Therefore, cornering loads taken when a car is covering a flat piece of asphalt cannot be expected while traversing over curbs, and the astute driver will try to ask less of the car dynamically then and there. For that reason, it always helps to try and get the turning done before the brunt of the curb is crossed over.
Depending on the layout of the corners, this isn’t always possible. In tight chicanes with a pronounced central curb, huge amount of time can be gained if the curbs are shortcut in the right way. It always pays to try to attack the curbs as straight as possible, even if it means taking an approach that’s not quite textbook; sometimes the out-in-out line isn’t as effective if it means the car is still turning as it mounts the curb. This will save time and keep momentum up.
As long as the car spends as little time as possible while running through the technical section, it’s occasionally permissible to do a little turning after the corner. In other words, running straight over an apex curb and then turning is useful if that curb coincides with a challenging section of corners; you want to spend as little time navigating that section as possible.
Curbs are less useful when the surface is wet. In fact, the painted curb is rendered as slippery as ice during a rainstorm, sometimes even a day or two afterwards, and need to be avoided. Even at high speed, when the driven wheels aren’t as traction-limited and the wings are pushing the car into the asphalt, the curbs are an easy way to ensure a crash, and probably a big one considering the speeds one’s traveling.
Like just about everything in racing, it’s a matter of horses for courses. If the car is in for a long haul, say in an endurance race, sometimes curbs ought to be avoided, since there’s no denying that graunching the suspension and chassis can hurt the driver, if not the car. There’s no denying that if the abuse doesn’t damage the chassis, it will stress the tires. Whoever wants to finish first at the end of twenty-four hours must be able to nurse their equipment and ensure a consistent pace of their own, even in resilient modern cars. Qualifying is another story, and successful curb-hopping can mean the difference between the last and first – and that’s not hyperbole.