Bump Drafting

Bump drafting is a racing technique where a driver gently pushes the car in front by making contact with its rear bumper, transferring momentum to increase the speed of both vehicles.

This technique is most commonly seen in NASCAR racing, particularly on superspeedways like Daytona International Speedway and Talladega Superspeedway. These tracks feature long straightaways and high speeds where cars naturally bunch together in tight packs, making it difficult to pass using traditional methods.

The physics behind bump drafting is straightforward. When two cars travel close together at high speed, they reduce air resistance for each other. The trailing car experiences less wind pushing against it, while the lead car gets pulled along by the vacuum created behind it. When the trailing driver adds a gentle push by touching bumpers, this momentum transfer causes both cars to accelerate beyond what either could achieve alone.

Executing a successful bump draft requires considerable skill and trust between drivers. The trailing driver must time the contact perfectly and apply just the right amount of pressure. Too much force, especially when entering a corner, can upset the lead car's balance and cause it to spin out of control. This is why bump drafting is typically reserved for straightaways rather than turns.

Multiple cars can form what's called a drafting train, where several vehicles work together in a line. Each car pushes the one in front, creating a chain effect that benefits everyone involved. These trains can move significantly faster than individual cars, which is why you'll often see drivers forming temporary alliances during races.

The technique is sometimes called slam drafting, though this term can imply more aggressive contact than what's typically considered safe or acceptable. Race officials monitor bump drafting closely and may penalize drivers who make contact that's deemed too aggressive or dangerous.

You won't see bump drafting in Formula 1 or other open-wheel racing series. F1 cars have delicate front wings that would shatter on contact, and the entire car design prioritizes aerodynamic efficiency over durability. NASCAR vehicles, by contrast, are built like tanks with reinforced bumpers specifically designed to withstand contact during close racing.

Some tracks and racing series have implemented restrictions on bump drafting due to safety concerns. Officials may prohibit the technique during certain phases of a race or issue penalties for contact that causes accidents. These rules help balance the competitive advantage of bump drafting against the risks it poses to driver safety.