How Dragster Tires Work
Ever wonder how dragster tires work? This video explains the forces at work and how tire technology is up to the challenge.
An NHRA Top Fuel dragster is a sophisticated machine, Every component is engineered to achieve a specific and predictable result and to measure every aspect of its own performance.
With 11,000 horsepower, a top fuel dragster will burn 15-20 gallons of nitromethane in their 3.6-second, 335-mph 1000-foot run. Not long ago, these cars were up over 340 but over a 1/4 mile — today, the run is limited to 1000 feet because the cars were just too fast.
The Goodyear tires on these cars cost over $900 each (frankly, we thought they’d cost more). They weight 48 pounds each and they last about 8 runs, which comes to about 1.5 miles.
Manufactured in Goodyear’s Akron, Ohio, plant, the tires stand 36 inches tall and 17.5 inches wide.
The insights here are largely drawn from racing engineer Chuck Hallum’s SAE paper, “The Magic of the Drag Tire.” The story starts after a burnout to heat the tires’ rubber and the full-power run begins.
VIDEO: How Dragster TIres Work
SQUAT IN THE NAME OF SPEED
Dragster tires work by providing massive grip — theoretically, throughout the entire run, but it all starts with the launch. This is the moment that you see that massive squat as 11,000 horsepower is clamoring for grip. The massive torque channeled through the rear axle shifts the load of the car rearward and tries to twist the tire on its 16-inch beadlock rim.
The sidewalls wrinkle as the tire—which is running only 6.5 psi or so —shrinks in radius by more than six inches and the tread effectively balls up at the front of the contact patch. That compression of the tire expands the contact patch to almost 250 square inches—larger than two side-by-side sheets of 8.5-by-11-inch paper. The compression of the tire also means that the final-drive ratio is effectively shortened for a harder launch. By the time the tire has released the torque stored in its wrinkled sidewalls and tread and grown back to its original size, the Top Fueler is already pulling 4G’s which is about what an astronaut in an Apollo rocket experiences at liftoff.
SWOLLEN AT SPEED
After the car launches, the inertia expands the tire to as much as 38 inches in diameter, and simultaneously lengthens and narrows the contact patch. This effectively lets the final-drive ratio grow taller for higher speeds and reduces rolling resistance as the vehicle hits terminal velocity.
A FAST FINISH
As the dragster finishes its run, the engine is shut down and its compression helps bleed speed from the dragster’s run. The rear tires then distort again as the car slows, sometimes developing flat spots at their trailing edges. But those big parachutes do most of the work at this point.
Attention to each of these stages by the tire engineers determine how dragster tires work. You can bet that every part of these tires are engineered using the latest proprietary methods and then tested to exhaustion.
The technology has advanced over the last 60+ years and for a time, these car were well ahead of the tire’s capabilities. For years, professional drag racers often remarked that engine and chassis advances were outpacing tire advances. It seems today that the tires are more than up to the task of handling all the horsepower that these race teams can throw at them.
Goodyear has continuously improved these tires with a singular focus on safety. The result has been shattered records all without sacrificing safety.
Technology for racing tires across all forms of motorsports has improved and today, even hot rodders and weekend warriors can buy drag racing tires for their play car.
The next time you watch the Top Fuel funny car and Dragsters run, remember that without Goodyear Tire, these cars would be nothing but noisemakers.