The more your car weighs, the faster it will go on a downhill ramp. Most rules specify a 5 oz. maximum weight. Most Pinewood Derby cars weigh between 1.5 oz and 3.5 oz (depending on design) without weights so a car may need 3.5 oz or more of additional weight.
Steel Cylinders
Steel Cylinders are ideal for bringing the weight of your Pinewood Derby car up to roughly 5 oz. Each cylinder weighs about 1/4 oz. The package comes with twelve cylinders for a total of 3 oz.
The best way to install these weights is to drill one or more 3/8" holes in the back or bottom of your car, insert the weights in the holes then glue them into place.