1. The class is open to three axle truck tractors with commercially available tandem drive axles. Driving steer axle not allowed. Vehicle license and inspection are not required.
2. The weight of the driver and vehicle not to exceed 20,000 lbs. Trucks may be split weighed at events that do not have a scale long enough to weigh the whole truck at once. If one truck in the class needs to be split weighed due to its length, all trucks in the class will be split weighed. When split weighing, the suspension must not be chained and air bags must all have the same pressure in them at the time the truck is weighed. In the case of a solid rear axle suspension, the air pressure in the front drive air bags must remain the same when weighing the front and rear of the truck. A 1% variation in the weight of each truck will be used when split weighing.
3. The truck frame must be of the same style as factory available C channel frame normally found on class 8 trucks. The steer axle, along with front and rear suspension must be commercially available for a class 8 truck application. No air bags permitted on the steering axle. The addition or removal of springs, airbags, torque rods and shocks on the rear tandem is permitted. No hydraulic cylinders. No suspension component can be more than 18” from center of drive axle except for factory equipped components.
4. Transmission must be a make and model commercially available in a class 8 truck. Internal modifications permitted.
5. Trucks with air ride suspension must be equipped with chains or some type of limiting device on both drive axles to prevent the height of the frame from changing during the pull. Limiting device must not have any ‘give’ built in. Solid rear drive axle suspension permitted, however front drive must be chained or limited. Chains or limiting devices must be tight (no slack) when the hitch is measured. Four short chains or cables from the side of the frame down to the axle housings is recommended. No chains and binders going up and over the frame rails allowed. Maximum air pressure in the suspension airbags must be limited to 80psi by installing an air pressure regulator in the leveling valve supply line. An air pressure gauge mounted at the regulator in a visible position must be present to check air pressure. This is done to prevent breakage of the suspension limiting device or failure of the airbags due to an over pressure condition. Breakage or failure of a chain or limiting device while hooked to the sled will be cause for disqualification.
6. Tires must be DOT approved truck tires. Maximum tire size to be 11R24.5, 10x22 or 315/80R22.5. Maximum tread width 10”. No bar type or agriculture type tread. No tire cutting or grinding allowed. No tire chains or cables allowed.
7. Puller must supply their own hitching device. Hitches must pull from a standard fifth wheel. Center of fifth wheel must be located in a position between the center of the front drive axle and the center point between the drive axles. There must be a minimum of 66” of unobstructed area from the center of the fifth wheel forward to the first obstruction (cab, sleeper toolbox, headache rack etc.). Hitch cannot be longer than 7 feet measured from center of rear axle to hook point. Hitch must have an adjustment range from 20” down to 16” with suspension in the ‘pull ready’ position. Hooking point must have a minimum 3.0 inch x 3.75 inch opening for sled hook (3.75 inch being front to back of hitch point). Hitch height will be measured with suspension inflated and chains or limiting devices tight.
8. Extra ballast weight is permitted. Weights or brackets cannot interfere with hooking the sled to the hitch. Weights or brackets cannot extend more than 51” rearward past the center of the rear drive axle. Weights on front of truck cannot extend more than 24” forward of the stock forward most point.
9. Engine must be a make and model that was commercially available in a class 8 truck. No multi engine setups allowed. Internal modifications to increase the displacement are permitted. Cylinder block and cylinder heads must be OEM castings. A single turbocharger is permitted with a maximum intake wheel inducer size of 4.100”. Turbo size will be checked using a 4.200” plug. Turbo cannot be bushed down from a larger size. No oval shaped inducer bores. Compressor wheel must extend into the inducer bore and cover the map groove. Factory style map width-enhancement groove is permitted; maximum width .280”, no other means for air to get to the compressor wheel are permitted. No slots or grooves that face completely forward from the intake wheel out.
10. Turbocharger intake must be accessible for inspection by tech official. Competitors must be prepared to expose the inlet of the turbo at each pulling event during tech inspection.
11. Trucks with fiberglass hoods must have a turbocharger shield mounted under or inside of hood. Shield to consist of .125” steel or aluminum mounted to contain debris in the event of a turbo failure.
12. Water only injection is permitted, windshield washer fluid is not permitted. No ether, methanol, propane or any other flammables or combustion enhancers are allowed in any form. Commercially available diesel fuel is the only fuel allowed.
13. Truck must be equipped with a SFI approved clutch/flywheel assembly. Engine bell housing must be shielded 360 degrees with any one of the following: a SFI approved shield; SFI approved scatter blanket(s) securely fastened and overlapped at least 6”. Automatic transmissions must be completely covered by an approved scatter blanket.
14. One scatter shield must be on all universal joints beyond the rear of the transmission. Scatter shield must be of a solid construction, 5/16” thick steel minimum and be able to contain debris or direct debris toward the ground. Scatter shields not required on the interaxle driveshaft provided the top of the frame between the rears is securely covered with minimum 1/8” aluminum or steel. One drive shaft loop must be installed on any drive shaft over 36 inches long including those with a carrier bearing. Driveshaft loop should be near the center of the shaft and be capable of keeping the shaft from coming out of the vehicle in the event of breakage.
15. A minimum of one 4” diameter clear light must be on the rear of the truck, must be activated by transmission when shifted into neutral. Truck must be equipped with a transmission activated neutral start switch or a clutch switch so that the starter will not engage unless the transmission is in neutral or the clutch is fully depressed.
16. Working rear wheel brakes are required on both drive axles. Parking brake chambers are required on at least one drive axle.
17. Exhaust must discharge vertically, turnout style pipes allowed. Two minimum 3/8” diameter bolts must be installed in the exhaust pipe after the turbo at a 90 degree angle to each other, within 1 inch of each other.
18. An emergency engine air shut off is required. Shutoff must be capable of being operated from the driver’s seat. A 2” diameter ring must be at the rear of the truck to operate the shutoff from the sled. Ring must be as close to center of the truck as possible.
19. Engine driven cooling fans must have fiberglass blades, metal blades not allowed. Fan must be inside a shroud.
20. Engine and radiator must be in the original OEM location.
21. Truck must be equipped with a master electrical disconnect switch mounted near the driver’s side door steps and easily accessible to someone on the ground.