These 2022 HOPRA rules. They apply to our Viper V-SPEC "Lexan" class of car. Differences between HOPRA rules are indicated in red.

Legal chassis’ are: : BSRT G3/G3R/G3RS/G3RSB, Slottech T1/T2/T3, Wizzard Storm/Fusion, Viper V1 (V-SPEC)

    1. The chassis must be stock, readily available, “HOPRA Approved” and cannot be machined, sanded, or cut except to provide the following:
      1. Add, remove, or re-add body mounts.
      2. Reinforce and/or replace pickup tabs.
      3. Add axle retainer.
    2. All magnets shall remain in their stock location. No material or method may be used to restrict the movement of the magnets.
    3. Only “HOPRA Approved” Compression Molded Ceramic Grade polymer traction and motor
      magnets may be used, see SPEC STOCK CAR CLASS RULES for specific manufacturer part
    4. The gauss reading of the traction or motor magnet shall not exceed the following criteria. This is taken after 5 min cool down period and at the lowest point on each magnet as it runs parallel to the rail. Any reading above the figures below will be cause for disqualification or rejection at tech:TRACTION: 1680 gauss maximum
      MOTOR: 1250 gauss maximum.
    5. The guide pin can be a stock replacement. It may be glued in place but shall remain in any one of the stock  positions.
    6. The armature must be stock or a hot stock. The minimum ohmage allowed shall be 5.8.
    7. There are no restrictions on the armature bushings or axles. Ball bearings are not allowed.
    8. Gear ratio must be a 7-tooth pinion with a 23-tooth crown gear. No metal gears allowed.
    9. The front wheels, tires and axles may be any readily available parts.
    10. Rear tires shall be readily available solid silicone, rubber, or urethane replacement tires. Rear wheels shall be readily available double or single flanged replacement wheels.
    11. Electrical systems shall be stock or stock replacement. Adjustable brush tension is allowed. Physically attaching brushes to springs (using glue or other substance) or spring arm is allowed. Plated parts are allowed. Shunts are not allowed.
    12. The use of glue shall not be allowed on the chassis, magnets, or bulkheads. Body mounts, guide pin and armature bushings may be glued into place.
    13. Track voltage will be set at 15.1 volts