Kub Kar Races

On Saturday my son participated in the Kub Kar Races.

Little hopeful faces staring at the finish line.

Two prize categories: fastest car and best design.

He got into the top 12! The top 6 got a trophy, but he was still very proud.

Now we need to think about the car for next year. So I wonder - what makes a car win, what is the winning element? Of course, gravity and friction are the two ingredients... The cars have to be made from the "Kub Kar Kit" and are to be no more than 142 grams (this is weighed by a very sensitive scale prior to the race). We lubed the wheels with WD40 (Ted told us that graphite is better). What would make a winning car? Placement of the weight? Maximizing the weight? Any ideas?

His car third from the left.