Pro Stock Semi-Truck Rules
Updated: Jan 19
Unless specifically outlined below in the class specific rules, the Truck General Rules
and the overall General rules outlined above apply.
1) Maximum weight permitted (including driver) is 20,000 pounds.
2) 250-inch maximum wheelbase.
3) 102-inch maximum width.
4) Weights cannot extend rearward more than 51 inches from center of rear axle.
Weights cannot extend more than 24 inches from the stock manufactured farthest
point forward of the vehicle.
5) All tires must be road-use approved tires available to the public. Dual wheels and
dual tires must be used on the rear axles. No cutting of tires permitted. Maximum
tire size limited to: 11.24.5 x 8.25, 11 x 22.5 x 8.25. No split rim or wedge lug type
6) Only tandem axle semi-trucks will be permitted to compete. No front wheel drive
allowed. No single axle trucks. No dump trucks. No specialty trucks (well-drilling,
wreckers, boom trucks, etc.)
7) Rear axle must be rigid to the frame in all directions. Axle must not move from
main frame of truck. If tires on rear axle lose contact with the ground while hooked
to the sled, this is grounds for disqualification.
1) Vehicle must be stock appearance for that year, model and make of truck.
2) Engine must be 12 inches within stock location
3) Engine limited to 1000 cubic inch maximum.
4) Fans must be fiberglass bladed. A complete 360-degree shroud must encircle the
fan and be securely fastened. A heavy fiberglass shroud is recommended.
5) One production available commercial truck engine only will be permitted.
6) OEM cylinder head for same model and series engine required
7) OEM exhaust manifold or aftermarket manufactured manifold, for same model
and series engine required with 3-inch maximum adapter plate to match turbo to
exhaust manifold. No inner/after coolers.
8) All exhaust systems must discharge vertically through the hood or behind the cab
with cross bolts in the horizontal portion of the exhaust system.
9) The use of a P-Pump is allowed for all trucks. Must not be larger than a P7100
1) All trucks will have 360 degrees 5/16th inch thick metal shield around universal
joints. Any drive shaft over 50 inches must have safety loops.
2) Foot throttles must have a toe strap and a positive two-way mechanical linkage.
3) All batteries must be mounted outside of cab and be securely fastened in place.
4) All vehicles must have working brakes on all rear wheels.
5) Vehicle must have firewall.
6) Air bags or air springs and/or all mechanical lift mechanisms on front steering
axles are not permitted.
1) Trucks must have a frame mounted hitch assembly. Hitch can have no connection
to the rear axle or bumper assembly. Hitch can be no shorter than 34 inches,
measured from the center of rear axle to the hook point, and no longer than 30
percent of wheelbase. Maximum hitch height is 18 inches.
1) a. Box Turbo (info coming soon)
b. 88MM with/without MAF can run with an air to air intercooler c.
Single turbo only, unless ACCERT, at discretion of the RRTTPA board.
2) Must have air shut-off on turbo that can be activated by the driver and also
activated by sled operator. All vehicles must have an operable kill switch hitch
located directly in line with the point of hook. A minimum of a two inch solid ring is
required for connection with a minimum of 1/8 inch cross sectional thickness. The
sled cable will be attached to this ring.
3) Turbocharger must be enclosed in the engine compartment; they may not be
visible from outside the truck. Turbochargers that are not under the hood must be
completely shrouded except for inlet/exhaust pipes. Turbochargers under fiberglass
hoods must be completely shrouded except for inlet/exhaust pipes. Shrouding must
be equal to or greater than .060 steel or aluminum.
Fuel & Water
1) The use of a P-Pump is allowed for all trucks. Must not be larger than a P7100
2) Electronic fuel systems allowed.
1) All automatic transmissions must be covered and protected by an approved
2) All competition vehicles are required to have steel clutch assemblies. No cast
assemblies permitted. All bell housings must be covered with and protected by an SFI
approved blanket with 6” overlap.
3) Only mechanically activated clutches are permitted.
4) All pulling vehicles must be required to have a steel plate or billet flywheel. The
flywheel must be made of steel with the following mechanical properties: tensile
strength of 60,000 PSI and yield strength of 40,000 PSI. Any aluminum or magnesium
flywheel that meets or exceeds SFI specs will be acceptable. Clutch papers must be on
file in the office and must be produced upon demand. SFI approved—new papers are
due each year.
All engines turning 3500 RPM and higher must be equipped with a harmonic
balancer or damper meeting SFI Spec 18, or All engines equipped with a non S.F.I.
approved harmonic balancer shall be shrouded with minimum 1⁄4 inch steel no more
than 1 inch away in direction of rotation, 360 degrees, to be securely fastened with a
minimum of 2 ears, each extending 1 inch in front of the hub. A bolt in the crankshaft
to hold the dampener puller is required. All balancers or steel hubs required to have a
retainer to restrict forward movement.
All pulling vehicles must be equipped with a 2 inch diameter white reverse indicator
light (back up light) mounted above the hitch. This light must be ON when the vehicle
is in reverse.