A couple more hints (I have an entire PDF document on speeding up PWD cars).<p>1)  You don&#x27;t need 4 wheels (except to stay on the track).  Lift one of them up slightly so the car is only resting on three wheels.  Don&#x27;t lift the forth wheel up high enough that it&#x27;s not able to help guide the car along the guide rail.<p>2)  Make sure the car rolls straight.  There&#x27;s a lot of friction against the guide rail if your car is constantly trying to turn into it.<p>3)  Make sure the inside of your wheels are sanded smooth.  You want any friction due to contact with the guide rail to be minimized.<p>4)  Put as much weight as possible at the back of your car.  Since that weight is higher up the launch hill, it will end up pushing the are longer.  Think of it this way:  Gravity will stop pulling a front-weighted car when it reaches the roll-out.  With a rear weighted car, the back will continue to be pushed when the front wheels are on the roll-out.  You get an extra car length worth of gravity.<p>Many PWD events mandate the use of the stock wheels and axles.  The fastest car I ever saw used layers of teflon tubing inside the wheel hub and hypodermic needles for the axles - very smooth bearing surfaces.  Beyond the tips above, the most important tip is to eliminate friction in the wheel-to-axle bearing.<p>Good luck!