Conquering Curbs on the Track

Conquering Curbs on the Track
Popping two wheels in the air is just a part of touring car racing.

 

While most tracks are generally pool table-smooth, there is almost always a segment of the track that requires a bit of curb-hopping and assertive driving to get the best possible lap time. Surface changes are a part of racing, and with stiff suspension and unforgiving cars, learning how to approach them in the right way is crucial, since covering them properly is worth huge amounts of time, but doing so incorrectly can damaging your tires and suspension and lose you valuable lap time.

There are plenty of things to consider when approaching a relatively high apex curb – the shape of the corner or chicane, the amount of grip available overall, and the stiffness of the car. By bouncing over an apex curb, you can, in theory, straighten the corner out and make the radius larger, and carry more speed through the corner. This doesn’t necessarily work in practice, though, since again, there are plenty of factors that come into play.

 

Conquering Curbs on the Track
Karts love curb-hopping, but their short wheelbase makes them very snappy, and their lack of suspension can fire them into the air.

 

The shape of the corner dictates how much curb should be used, for one. In a chicane, for instance, often the first curb can be attacked to shorten the distance through the complex, but the final corner requires a more delicate approach, since getting good traction is very important. The basic idea is that getting a handful of opposite lock at the exit is, generally speaking, not worth the shorter distance covered.

 

Conquering Curbs on the Track
In chicanes, sometimes the last apex curb is best avoided for the sake of traction, but it depends on what precedes and what follows the corner in question.

 

To reduce the chances of upsetting the car, it needs to be as straight as possible when covering the curb itself. For this reason, get direction changes done before attacking the curb – covering a curb and trying to do much turning inevitably results in a big slide. Determining how much curb to take is another question in itself, and needs to be worked out on a case-by-case basis.

The amount of grip on the painted curbs might pose an obstacle depending on the circumstances, too. In the rain, it’s usually best to avoid them entirely since they can be as slick as ice. If there’s much more grip on the asphalt itself, regardless of the shape of the corner, sometimes it’s worth avoiding the curbs. There are so many different combinations that there are no overarching truths, and finding the quickest route takes a studied approach.

 

Conquering Curbs on the Track
Stock cars revel in curb hopping, thanks to their large sidewalls and soft suspension.

 

However, there are some basic generalities that need to be kept in mind for the sake of lap times, as well as safety. Cars with a lot of aerodynamic dependence, like prototypes and single-seaters, will almost always be less forgiving over curbs, for two reasons: their suspension stiffness and the aerodynamic platform. Since they are so much stiffer than GT cars, stock cars, or production cars, they’ll never be as compliant and the penalty for getting a curb wrong is much worse.

Their downforce comes as a result of a stable aerodynamic platform, which means that a consistent amount of air is flowing over the wings and underbody. If the car is thrust over the curbs and its attitude changes significantly, it’s possible to lose the aero grip momentarily by depriving some part of the bodywork’s airflow, and for that reason alone, the curbs are especially lethal at high-speed.

 

Conquering Curbs on the Track
Flying over the curbs is possible with a high-downforce car.

 

Conversely, hopping curbs in a comparatively softly-sprung car is easier and, at times, an absolute necessity. Sometimes, the compliance of a GT car or a stock car allows for a bit of curb-rotation without much time lost. Essentially, it’s a way of turning a heavier, unwilling car, and the grip available from the suspension travel can mop up some of the post-apex sliding that would hinder the progress of a stiffer, less forgiving car.

Of course, taking too much curb is a great way to damage the underside of a car. Suspension arms tend to take a beating with really aggressive hopping, and the undertray can be punctured if too much is taken. Additionally, it’s a great way to overheat tires, as the sliding and bouncing tends to stretch the carcass and raise temperatures very quickly. In short, determining where the curb is beneficial takes some discretion, and while a curb should be attacked with confidence if it’s ultimately the chosen path, sometimes avoiding the curb for the sake of mechanical sympathy is worth considering, especially in longer races.

Essentially, curb climbing is done to maximize the radius of the corner; it helps as long as it shortens the real estate covered, and detracts from the overall performance if it results in a time-sapping slide. Surface conditions and corner priority always play a role in choosing how to approach the curbs, but avoiding them entirely is almost always a mistake. Once some confidence is summoned and the experimentation pays off, jumping over the curbs is a wonderful experience. Like dancing on a knife edge, the car is usually on verge of a spin, and the jumps, minor twitches, and compression feel like horrible abuse. With whole seconds available to the master of these sections, the reward is always worth the worry, and worth the trip to the chiropractor.

 

Conquering Curbs on the Track

About Tommy Parry 101 Articles
Tommy Parry has been racing and writing about racing cars for the past seven years. As an automotive enthusiast from a young age, Tommy worked jobs revolving around cars throughout high school and tried his hand on the race track on his twentieth birthday. After winning his first outdoor kart race, he began working as an apprentice mechanic to amateur racers in the Bay Area to sharpen his mechanical understanding. He has worked as a trackday instructor and automotive writer since 2012 and continues to race karts, formula cars, sedans and rally cars in the San Francisco region.
  • Cobranut

    I’m pretty used to using the curbs, but I remember my first time at Road Atlanta.

    Several laps into practice I followed another car through the esses, and watched as he drove straight over the curb exiting turn 5.
    There’s another whole lane of pavement, which is difficult to see from inside the car. 😮

    The next lap I tried his line, and despite the little jump over the curb, found I could get on the power much earlier and exit 5 a lot faster than I had been.

    • Francis Dance

      Exactly my memory of Road Atlanta from my (only time) 1994 SCCA Runoffs experience. That was before they put the chicane in there, which made the bridge turn very exciting in my SSGT Firebird.

      • Cobranut

        As if it’s not exciting now. LOL
        Coming under the bridge I watched two SCCA Spec Racers get together right ahead of me. The one on the right spun onto the grass, and the other one backed HARD into the concrete wall, disintegrating the car. Luckily he hit backward and his seat absorbed most of the impact.

  • Cobranut

    I think you need to reevaluate your caption for that F1 car.
    If you look closely, his right front suspension pushrod is broken free from the bellcrank at the inner end. His landing is going to be very unpleasant.

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