OFFICIAL RACER RULES
Weight will not be over 5.000 ounces by official scale. The scale used is calibrated at each race, and racers can request the official to recalibrate, if needed. Outdoor races sometimes cause variances, due to wind and humidity. So, be prepared to add or remove weight at check-in if very close.
Entire car, including wheels and axles will be 2.75 inches wide or less, and 7 inches long or less.
Width between the wheels is 1.75 inches minimum.
WHEELS AND AXLES
Cars would use the pre-cut axle slots. Axle slots can also be recut and moved on the block, as long as the wheelbase remains equal to the original wheelbase of 4 5/16 inches. A variance of up to 3/16 of an inch will be allowed.
No bearings, washers, bushings, or springs. Free-wheeling, no "devices".
Cars must run on standard derby plastic wheels, using standard derby nails or axles.
Only dry lubricants, like graphite, are allowed.
If any car has modifications that go against the "spirit" of the traditional race, officials may require changes during check-in.
OUTLAW RACER "RULES"
WHEELS AND AXLES
All we ask, is that cars will not damage the track, electronics, spectators, time/space, or other cars in any way. So, no rockets, no Ben Hur spikes, no flux capacitors, etc.
During check-in, race officials will need the driver to explain the "outlaw" modifications, and can disqualify cars from running, if they have any concerns about track damage or safety.
NEED A CAR KIT?
Kits can be found at multiple locations around town, as well as online. The local Scout shop always has their high-quality kits available, as well as weights and other accessories. The kits at the Scout shops are the most authentic, and come with everything you need, minus weights, for less than $5. You can also find kits year-round at the local hobby and arts/crafts stores like Hobby Lobby or Michael's.
MDnA Inspection Box
This 3d-printed inspection box will quickly check measurement rules on derby cars. The box will measure car length, width, width between the wheels, and clearance. The posts on the box will measure axle distance, by lining up one axle with the small post, and verifying that the second axle will land somewhere on the larger post.
If there are questions on measurements, other tools will be at the race for confirmation.
Feel free to print your own inspection box by downloading it from TinkerCAD.