MODIFIED CLASS RULES
These are 2022 HOPRA Nationals MODIFIED rules. Exceptions or differences to HOPRA rules are indicated in red.
Legal chassis are: BSRT T2/G3/G3R/G3RS/G3RSB, Mattel/Tyco 440×2, Slottech Panther/Panther 02, Thundercat T3, T1X, Tomy AFX Super G+, Wizzard Storm/Fusion, Viper V1
- The chassis must be stock, readily available, “HOPRA Approved” and cannot be machined, sanded, or cut
except to provide the following:- Add, remove or re-add body mounts.
- Reinforce and/or replace pickup tabs.
- Add adjustable Brush tension.
- Add axle retainer.
- All magnets shall remain in their stock location and cannot be cut.
- Only “HOPRA Approved” compression molded polymer traction and motor magnets may be used,
see COMPRESSION MOLDED POLYMER MODIFIED CAR CLASS RULES for specific
manufacturer part numbers. - 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 these figures will cause disqualification or rejection at tech.
TRACTION: 1680 gauss maximum, MOTOR: 1250 gauss maximum.
- Only “HOPRA Approved” compression molded polymer traction and motor magnets may be used,
- 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.
- Any nonmagnetic materials may be employed to restrict the movement of the magnets.
- The armature must be stock or hot stock. The minimum ohmage allowed shall be 5.8.
- 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.
- Rear tires shall be readily available in solid silicone, rubber, or urethane replacement tires. Rear wheels must be readily available, double or single flanged replacement wheels.
- There are no restrictions on the armature bushings (may be glued in). Ball bearings are not allowed.
- There are no restrictions on guide pin, gearing, or axles.