I see a lot of cars that are sitting low to the ground to try to increase the aerodynamics of the car.  I will first admit I am not a mathmatician, possibly someone who is can give more insite here.  What I would like to comment on is that the cars are designed to sit so low to the ground that they tend to rub the ground.  The miniscule advantage that may be gained aerodynamicly is lost (I would guess thousands of times over) to the friction of the car constantly dragging on the ground.  When you are designing your car, it is a good idea to look at all forces that are acting on the car.  Take all of them into consideration and procede forward in a logical manor.

Bottom line is the sugestion to set your tires a little lower and not have the car drag over bumps in the road.

A very valid point. We purchased a Blue Sky Designs Aerocoupe about three years ago, new might I add, and the front of it sat 3/4" off of the ground. Looking back at it, I have scraped at EVERY track we competed at, and it was the main reason we did not like competing with our BSD chassis. Here's another aero secret. If the car is about 1 1/2" to 2" off of the ground, and it has a FLAT underpanel, it will be more areo efficient then someone who has their car 1/2" off the ground with a round or open bottom.

In Nebraska cars must set higher off of the ground than what the sidewall height of your tires are. That way if you have a flat the body won't drag. stan r

That's a very interesting rule, actually our SCCA rules are the same way with the exclusion of Formula and Sports Racers.

The Electrathon America rules states that the car must not touch the ground when any or all of the tires are totally flat. If you are running hookworms then your car needs to be about 1 1/2" off of the ground. I tell my students they need to be able to slide a 2" X 6" under their cars to be legal. That is 1 5/8". In the NW we use a transponder system to count laps and so have a wire pickup network screwed to the track. If a car scraps it will pull up our wiring so we black flag cars that scrape on anything but the bigger bumps in the rough parking lots we race on.

stan r wrote:

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In Nebraska cars must set higher off of the ground than what the sidewall height of your tires are. That way if you have a flat the body won't drag. stan r

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We try to enforce this rule here too.  One issue tends to be a long car with the front tires sat way back.  When a tire goes flat the nose can drop far more than the sidewall height of the tire.  I have also seen many frames bend/break durring the race.  The car just slowly settles lower and lower.  We came close to a very big problem Saturday when a car that had not been a problem with dragging dropped down and nearly ripped out out wiring to the timing grid.  The wides were damaged but still functional after the "snag".

Aaron