New Hampshire's Original Diesel Performance and Repair Specialists



Rock Crawler Mod Class Registration and Information

What has been called the best man made rock crawl course in New England, put your crawler to the test and try to do it the fastest.  The course is built and ran by crawling enthusiasts who want to have just as much fun as the competitors! 

Rock Crawl Mod Class:

Mod Class Rules and Regulations:


  1. Both differentials must use some form of locking device.
  2. Portal axles are not approved for conversion.


1. Doors and tailgates may be removed.


  1. The brake pedal on the floor must operate all brakes.
  2. Competitors may use secondary brakes for operation individual brakes on the vehicle.
  3. Transmission brakes are not approved for primary braking. They may be used as a secondary brake or emergency brake.
  4. Pinion brakes are not approved, unless OEM on the stated (declared) vehicle. They may be used as a secondary brake or emergency brake. 
  5. Brakes must be in good working condition with adequate pads. Brakes that are worn out or oil soaked will not pass. 
  6. Brake lines must be in good shape without leaks and ran in a safe route from cylinders to brakes. 
  7. Master and slave cylinders must be in good shape without leaks. Adequate braking resistance at the pedal is required.


  1. Radiator must be covered so that, in the event of a break in the radiator or hoses, spectators, spotters and drivers are protected from the coolant spray and spill. 
  2. Radiators must be securely mounted. 
  3. Top mount (roof mount) radiators are not approved. 
  4. Radiators must have an OEM or adequate sized aftermarket overflow bottle, securely mounted, and connected to the radiator by an overflow tube. Overflow bottles may not be mounted over or in the passenger compartment. Overflow bottles may not be beverage containers.


  1. Batteries must be in good shape with adequate mounting to keep the battery in place in the event of a roll.
  2. All batteries must be of a non-spill type.
  3. Wires must be in a condition and position that is safe. Exposed or burned wires are not approved.
  4. A master kill switch that shuts down every electrical system is required to be mounted on the dash, clearly labeled and in proper working order. This switch must kill the engine when switched to the off position.


1. All engine sizes and configurations are approved.

Fuel System:

  1. Alcohol is not approved for competition as a main fuel (see above).
  2. Non-vented gas caps are mandatory.
  3. Fuel systems must be sealed with a rollover valve installed in the fuel vent line.
  4. Fuel lines must be ran from the fuel tank or cell to the engine in a safe route.
  5. Fuel lines must be free of leaks or cracks in hoses.
  6. Throttle assemblies must be in good order and work smoothly. Throttles that do not move smoothly throughout their entire range of motion will not pass.


  1. All OEM frames are approved. 
  2. Full tube chassis are permitted.

Roll bars/Cages:

  1. Six (6) point mounting cages covering the driver are required.
  2. OEM bars are approved for a portion of the roll cage.
  3. Round steel tubing (D.O.M.) preferred 1.5" O.D with 0.120" wall is compulsory for the basic roll cage. Aluminum and/or soft metals are not permitted. Roll bar construction must be welded. Northeast Performance Diesel must approve roll cages made of other material or in other wall thickness/diameters.
  4. Connection positions of the roll cage must tie into the frame of the vehicle; body mounts are considered a tie in point.
  5. Gussets must be welded in the four corners of the halo. Gussets may be tubing or plate steel.
  6. A minimum of .040 magnetic expanded or flat sheet metal, or 1/8" aluminum must cover the area immediately over the driver seat and be welded or bolted to the roll cage. Steel tubing must surround the roof panel.
  7. Northeast Performance Diesel recommends a spreader bar to be mounted under the dash area to connect the right and left A pillars.
  8. If doors are not ran, a bar running from the B pillar, at approximately shoulder height, to the A pillar, at approximately shin height, must be run. This can be a bolt in piece.


  1. Factory seats must be fastened to the tub in the factory mounting points or to the roll cage.
  2. Aftermarket seats must be attached to the roll cage.
  3. Mounting points must be in good condition without rust or corrosion
  4. An approved four-point harness is mandatory and must be worn at all times while on an obstacle.


  1. All steering components, u-joints, and fittings must be in good working order as determined by Northeast Performance Diesel. 
  2. Brake steering is permitted as a secondary form of steering but not primary.
  3. Hydraulic steering fluids must not leak.
  4. Hydraulic lines must be ran in a safe route and be in good shape, free of cracks or fraying as determined by Northeast Performance Diesel. 


  1. Suspension pivot points, connecting points must be free of cracks and in good physical condition as determined by Northeast Performance Diesel.


  1. All automotive-based tires.
  2. No tire size limit.
  3. Tire studs, screws, or anything added to the tire to aid traction will not be permitted.


  1. Wheels must be mounted onto the axle with minimum of five lug studs.
  2. All lug studs must have the proper nuts on them.


  1. All professionally built and sold electric, hydraulic, and power take off winches, with a minimum capacity of 5000 pounds on the first wrap of cable, are acceptable. 
  2. Rope/Cable must be in acceptable condition with minimal fraying or kinks. 
  3. Winch must be mounted using all factory-mounting positions on either the bottom or front and back. 
  4. Must be in working order.

Seat belts:

1. Seat belts must be worn at all times while driving or riding in a vehicle during an event.

Loose Articles:

  1. All items must be securely fastened to prevent injury in the event of a rollover. Coolers, miscellaneous parts, and other extraneous items are to be removed from the vehicle prior to each obstacle.

Fire Extinguisher

  1. Two completely full fire extinguisher must be mounted on the roll cage on both the right and left hand side of the driver. Extinguisher should not be mounted close enough to fuel cells or potential fire hazard areas that would make it dangerous to obtain.


1. All competitors riding in a vehicle must wear a DOT/Snell approved helmet while competing.

Injury Report:

1. Any competitor (driver or spotter) must report any injury to Northeast Performance Diesel prior to leaving the premises.

Drugs/ Alcohol

1. Drugs and alcohol will not be permitted in any degree during competition. Competitors who are found to be consuming or are under the influence of drugs or alcohol during competition will be disqualified from the event they are participating in.