Losses from: Friction between wheel and axle Friction between hub and car Friction between hub and nail end Air friction Wheel vibration Body oscillation (wheels out of round) Wheel rolling friction Wheel sliding friction on track or rail Angular acceleration of wheels
Part of this presentation is oriented around this idea...
Regardless of the lane in which you race, you should race in: The steepest lane, The shortest lane, The smoothest lane, and The slickest lane
Then, you will be racing in... The fastest lane!
But if you don't get to pick the lane, how do you make sure to get the fastest lane? By what you do to your car! That is why this presentation exists.
It isn't about weight in the back pushing the car down the track... Or about weight in the front pulling the car down the track. It is about how far the car drops as it goes down the track.
The amount of drop determines the amount of potential energy that can be turned into speed. With modern tracks, drop increases as center of mass is moved farther back in the car.
Make your car as long as rules allow. Locate the center of mass (balance point) as far back as stability allows. Stability includes sticking to the track and not sliding sideways.
This applies to modern tracks which start on a slope and flatten out toward the finish line. This does not apply to older style tracks which have constant slope or which have both increasing slope near the starting line.
Set axles so that car runs straight and level. Align as required.
You may analyze the track and find that raising the CM reduces the distance that it must travel. Right! But this usually fails because the CM is so far from the wheels. You must be on a very smooth track, and your wheels must create very little oscillation.