Back in the day drag racers did everything they could to get as much weight on the rear tires of their cars. With the wheels in the air, traction was at it’s highest, and cars would haul ass. With big tire cars, like NHRA Pro Stockers, that slowly changed in the late 1970s when crew chiefs worked at keeping the front tires just off the ground but not standing on the bumper. Wheelie bars of course became the norm and those cars now are designed to ride the wheelie bar out a certain distance and then settle down to keep air out from under the car as they motor down the track. But what about cars without wheelie bars? What about cars that are running on a drag radial? Those cars clearly need all the weight on the rear tires still right? Well…. No. Not even a little bit.
For the most extreme example of drag racing weight bias, look at Top Fuel Dragsters. They have a 300 inch wheelbase, with a lot of weight near the rear tires, but not on top of or behind them. They are designed to leave the starting line with the front tires just off the ground and to continue down the track with only enough weight on the front tires to maintain steering control. This is because that 300 inch long wheelbase makes the entire car a lever arm and the load on the rear tires is WAY higher because it is holding that heavy arm in the air, than it would be if all the weight in the car was over or behind the rear tires. This practice and methodology relates more to a radial car, or small tire no prep car, than you might think.
Why? Well the big reason is horsepower. If you have a naturally aspirated combination then more weight out back can work, but with a power adder combination, like a turbo car that makes ridiculous power just off the starting line, having too much weight out back will result in power wheelstands which can be a bad bad thing. Fun to watch, but not good on the car or the ET.
In this Tech Tip Tuesday video from Motion Raceworks, Doug Cook talks about weight bias in a radial equipped car that has a turbo combo, or other power adder combo, in it. It’s worth the watch, so enjoy.
