Bottoming Out

Bottoming out is when the underside of a race car scrapes or hits the track surface because the suspension has compressed as far as it can go.

Imagine a race car driving over a bump or through a dip in the track. The car's suspension—the system of springs and shock absorbers that cushion the ride—compresses to absorb the impact. If the suspension compresses completely, the bottom of the car makes contact with the ground. That's bottoming out.

This happens frequently in motorsport because race cars sit extremely low to the ground. Engineers design them this way to improve aerodynamics and create downforce, which is the force that pushes the car down onto the track for better grip. The problem is that leaving very little space between the car and the road means there's less room for the suspension to move before the underbody hits the surface.

Several factors cause bottoming out. High-speed cornering compresses the suspension as the car leans into turns. Aerodynamic downforce increases at higher speeds, literally pushing the car closer to the track. Bumps, curbs, elevation changes, and uneven surfaces all force the suspension to work harder. When these forces combine, the car runs out of suspension travel and makes contact with the ground.

The effects of bottoming out range from minor to serious. When the chassis hits the track, it can cause a sudden loss of grip because the tires momentarily lose their connection with the road. The car becomes harder to control and may feel unstable or start vibrating. Drivers often see sparks flying from the underside of their cars when this happens, especially at night races.

Repeated contact with the track surface causes excessive wear on components underneath the car. In severe cases, bottoming out can damage critical parts like the exhaust system, oil sump, suspension components, or even the chassis itself. These repairs are expensive and time-consuming, potentially forcing a car out of a race.

Teams work constantly to minimize bottoming out while maintaining the performance benefits of a low ride height. They adjust suspension stiffness, modify the car's ride height for different tracks, and fine-tune aerodynamic settings. Some racing series allow active suspension systems that automatically adjust to changing track conditions. Engineers also use special bump stops—cushions that provide extra resistance when the suspension nears its limit.

You'll see bottoming out most dramatically in Formula 1, where cars produce enormous downforce and run incredibly close to the ground. It also occurs in other forms of racing, including sports car racing, IndyCar, and even motocross, where bikes bottom out during hard landings after jumps. Finding the right balance between a low, aerodynamically efficient car and one that won't damage itself on the track is one of the ongoing challenges in motorsport engineering.