NASCAR Spring Rules & Regulations - Tales From The Workshop

NASCAR’s recent change in Winston Cup spring rules came about because of downforce in the body. There’s likely going to be another change in the rules by the time you read this, because some people are getting around the elimination of bumpstops by modifying their front springs to include fewer coils. It’s 8-½ inches now, and it could be a quarter-inch taller soon, with a minimum number of coils required.

Ideally, if you can get the front end of the car down on the ground, get the front skirt that’s 3-½ inches off the ground when you go through inspection to virtually drag around the track, the better it is. It seals off the air from under the car. While you’re doing that, you want to get the back of the car stiff and keep it there. We used to have 3,500-pound right front springs in the car, and it would roll over on the right rear in the corner. Finally, we got smart enough in the wind tunnel to say, “Wait a minute, that is definitely the wrong attitude to run the car when we’re trying to get every ounce of downforce out of it that we can.”

So, we learned to set the cars up differently. We put the stiffest right-rear spring in it that the driver could stand and that held the quarter panel up in the air. The whole idea was to get the car to go through the air in a wedge shape instead of letting the right rear fall down and lose total downforce. You’d get air under the car and lose front downforce. Then you’d get the bumper down close to the track and lose rear downforce.

Before NASCAR changed the spring rules, the trend was to put these things on bump rubbers, put baby-buggy springs in there, really soft stuff, and let the thing fall down against the bump rubbers and ride on them. Now, if you got the car to drive well like that, then you were that much better as a crew chief. The drivers didn’t like that because it would go down and hit the bumpstops and feel like a 3,400-pound go-kart. It would vibrate the fillings out of their teeth.

NASCAR eliminated the bumpstops. Nobody liked that a whole lot, but in the big picture, everybody has to do it, and that’s OK. It also seems to be brand-friendly, affecting the Ford, Dodge, Pontiac and Chevy about the same. Sometimes when you make a change like that in the attitude where you run the car, it affects a particular make differently.

With the new rules, there’s ordinarily 400 to 700 pounds of split across the front, and you put a big old sway bar in with that. If you have a 550-pound spring in the left front, you might have a 900- to 1,150-pound spring in the right front to match that to get the car to balance out right. Spring rates on the right rear have gone from 275 pounds in the old days at a place like Rockingham to 600-pound springs in the rear.

Sometimes you can get mad at NASCAR for the rules, but again, if you look at the big picture, it saves the teams money. When we had the bumpstops and soft springs in there, we were working on shocks like crazy. We were trying to come up with all kinds of trick pistons and stuff. We would go until we dragged, then the crew chief would come back the next week and say, “I’ve got to have another half-inch of clearance under the car.” You start looking and say to yourself, “Geez, we have the crankshaft as high as we can get it, the oil pan and the bell housing is dragging the bottom off it and the crossmember is digging into the racetrack ...” That caused a lot of work.

You get another half-inch of clearance and then they come back in three weeks and say, “I need another half-inch.” Something had to stop somewhere. All of a sudden, you wake up one day and realize, ‘Good God, we don’t even have an oil pan and our flywheel has to be 14 inches ...” We were jacking transmissions up in the back to try and get the 750-pound engine in. You can only get the crankshaft so high before it wants to start sticking the carburetor through the hood, and that means you have no air-cleaner clearance.

Like I said, though, it has to stop somewhere. Everybody has to deal with the same thing, so that’s OK.

Eddie Dickerson runs the chassis department at Hendrick Motorsports.