Mini Rod Tractors

 Limitations

  1. Modified minis are limited to a maximum of 575 cu. In. of naturally aspirated engine or 380 cu. In. of 6-71 supercharged small block w/10% overdrive.
  2. Naturally Aspirated engines less than 512 cubic inches are allowed to weigh 2,000lbs.
  3. Naturally Aspirated engines over 512 cubic inches and supercharged engines are allowed to weigh 1,950lbs.
  4. All engines are limited to (2) valves per cylinder.
  5. Engines are limited to (1) spark plug per cylinder

Driveline Shielding

  1. Modified Minis must meet general tractor shielding and safety criteria.
  2. All drive train, excluding additional manual transmission, must be enclosed in 5/16″ minimum steel or 3/8″ inch aluminum, round, inside diameter not to exceed 2 inches more that the outside diameter of the largest universal joint, fastened every 6 inches or closer, with 3/8″-inch or larger bolts, Grade #5, or butt and seam welded, and securely mounted to vehicle’s frame. Applies to all vehicles with exposed driveshaft. No more than ¼ -inch of end of driveline shall be visible with driveline shielding in place.
  3. Note: If U-joints are used in any drive shaft application, the shielding must be 5/16-inch steel or 3/8-inch aluminum with 1/8-inch steel insert in aluminum. The insert must be a minimum of 6 inches wide.
  4. All Modified and Modified Mini mounts, two rear engine mounts, and a support saddle for rear of transmission, with 1/2 –inch maximum clearance; OR
  5. Two front engine mounts, support saddle at rear of engine, with ½ inch clearance, and a mount at rear of transmission.
  6. Note: This is to prevent engine or transmission from dropping if breakage occurs.
  7. No portion of the tractor shall exceed 8 feet forward of the center of the rear wheel.
  8. Tread width (foot print) not to exceed 6 feet in width.

Drawbars

  1. Drawbar height to be 13″
  2. Drawbar length to be no shorter than 6″.
  3. Drawbar and hitching device to be one-piece construction, with a minimum of 1 inch solid steel material.
  4. No hollow tubing is permitted.
  5. Front part of drawbar is to have a minimum of ½-inch cross sectional thickness to remain on the front side of hole where drilled.
  6. Minimum ½ -inch pin.
  7. Drawbar height adjuster or hold up/down device to be no more than 5 inches from hook point. There must be a minimum of ½ inch metal remaining where hole is drilled. Hose clamps may not be used for any drawbar related devices.
  8. The drawbar receiver or the material where the front of the drawbar is attached must have a minimum of 1/4 –inch thick metal on each side of the horizontal pin drawbar.

Point of hook

  1. The point of hook is to have a minimum of a 2-inch round hole, maximum of 2-1/4 inch hole.
  2. The thickness of material around the hole must be a minimum ¾-inch thick.
  3. Point of hook to be no more than 3/4-inch cross sectional thickness.

Tires

  1. Maximum tire size is 18.4 x 16.1 with a maximum of 143-inch circumference when mounted on an 18 inch wide rim and inflated to 10 psi. The ground patch is not to exceed 19 inches on original tread.
  2. No tire repairs (boots, section repair, vulcanized spots, etc.;) will be allowed.

 Skid Plate 

  1. Skid plate must be of the two types listed below:
  2. Skid plate mounted to center of axle must be a minimum of 10 inches wide with rolled edges both front and rear. Plate must be a minimum of 4 inches in length. Plate must be centered and securely mounted to front axle and/or frame.
  3. Skid plate mounted inline with each frame rail (on both sides) equal in strength to frame rail material.
  4. Skid plate surface to be minimum of 2 inches wide and 10 inches long with a minimum 2 inch curve when measured from the front most part of rolled edge.
  5. Note: Both types must be able to support the weight of the front end when checked with a jack. Maximum ground clearance not to exceed 2 inches with front tires in normal operating position.

All general rules apply (where applicable).