Improvements on the wheels are possibly the most important improvement on the car. The nails or axles of the cars must be de-burred and polished. The wheels can also be polished. The best way to do this is by using emery cloth and a drill. One idea is to lubricate the wheels and axles by putting them in a bag with graphite.
Wheel alignment is also an important issue.
If the wheels are not properly aligned, then the car will rub against the guide rail creating friction, and thereby slowing the car. A properly aligned car can travel almost 8-10 feet on the ground. Different energies are affecting the race car while on the track. This formula describes how fast the car will move. When the car is actually on the track and moving it has kinetic energy.