Tools & Tips
Questions & Answers
Here are a collection of basic speed tips. These tips are allowed in most races, but please read and understand the rules for your local race before implementing any speed tips. Also, use eye protection when working on your car.
- Smooth the tread - This is accomplished by placing the wheel in a drill using a wheel mandrel (a tool sold at hobby stores), and then lightly sanding the tread with fine (600+) grit wet sandpaper. To make sure that the tread is evenly sanded, attach the sandpaper to a small flat piece of wood or metal, and then apply the sandpaper to the tread. Continue sanding for about 10 seconds on each wheel, making sure that the sanding time is the same for all wheels.
- Lift a front wheel - Lifting one front wheel off of the track by angling/bending an axle upwards will provide a speed advantage. But make sure that the center of gravity of the car is behind the center point of the car. Test spin the wheels, and use the poorest spinning wheel as the lifted wheel.
- Remove the burr by the nail head (if present) - Place each axle in a drill and use a small file to remove the burr.
- Polish the axles - Place an axle in a drill, apply some polishing compound (car polish, metal polish, jeweler's rouge, etc.) to a rag, and polish the axles until shiny.
- Maximum weight - Make sure your car weighs the maximum allowable amount (normally 5 ounces).
- Location of weight - Place the added weight such that the center of gravity of the car is ~1 inch in front of the rear axle.
- Maximum length - Make sure your car measures the full length of 7 inches.
- Aerodynamics - Avoid the use of streamers, flags, or any other material that could catch air.
- Attaching wheels/axles - Attach the wheels/axles to the car after all body work is complete. This includes drilling, cutting, shaping, sanding, painting, weighting, lubricating, and decorating.
- Wheel clearance - The clearance between the wheel hubs and the sides of the car should be about 1/32 inch (approximately the thickness of a credit card).
- Wheel adjustment - After the wheels are attached place the car on a flat surface such as a kitchen countertop. Use a ruler to measure the distance from the countertop to the bottom edge of each corner of the car. Adjust each axle up or down in the axle slot until the four corners of the car are the same height above the counter top and all four wheels touch the surface at the same time. If one of the front wheels has been purposely raised, then of course only three wheels will touch the surface.
- Wheel alignment - Attach a piece of masking tape (3 to 4 feet long) to a smooth, flat surface. Use a straightedge to make sure the tape is straight. Roll the car on the surface using the tape as a guide. The car should be able to roll 3 feet without veering off course. If the car turns within that distance, a
slight correction can be made by swapping wheels from side to side or front to back. If a larger correction is needed, then the front axle for a wheel that is touching the ground can be bent slightly, and then rotated until the car rolls straight.
- Gluing axles - After aligning the wheels, glue the axles in place using a small amount of white glue or epoxy.
Apply the glue to the axles at least 24 hours before the weigh-in. Do not use a thin glue such as super glue.
- Storage - After completing the car, store the car in a safe place (such as a padded shoe box). Do not play with the car, or roll it around; the car could be damaged.