Super Modified Class Rules

Super Modified Division:

**This class has an 18+ age restriction due to the performance and modification made to the mowers

** This Class has an exception to run a maximum of 116 octane. NO alcohol fuels. 

1. Chassis;

• The mower must be of lawn tractor origin and built on a lawn tractor frame.

• Bucket style seat mandatory, driver must be securely seated for side-to-side impact. 

• Front and back tube style bumpers are mandatory, Bumpers must be bent or capped with no sharp edges and no open spaces between bars for tires to get caught in. Bent ends are preferred but capped flat bumpers are accepted as well. The back bumper must have a hoop-style backguard to protect the driver from rear impact.

• Nerf bars are mandatory, they must offer sufficient protection to the driver's ankles. Tube-style design is mandatory. The gap between bumpers must be closed according to the tech director’s discretion. Either sheet steel, plastic or expanded metal are some of the safe options to fill the nerf bars to avoid a driver getting their foot caught.

• Nerf bars can not protrude past the extremity of the tires and must not be recessed more than 1” from the outer face of the tires.

• Front axles may be fabricated or reinforced but must be mounted in the original location, a one-piece design securely bolted or welded to the chassis.

• Chassis can NOT be widened, narrowed, lengthened or shortened by any means. Discrete holes, notches or removable panels are accepted to facilitate the building/repairs on the chassis. Holes/notches will most likely be needed to retrofit a solid axle construction, implement a gearbox or installation of hydraulic braking system.

• The only chassis modification allowed is the lowering of the back tubular section of the body where the seat is to be mounted. It is preferred that all mowers be built to keep the driver as low as possible to the ground to eliminate any stability issues where they arise. 

• All cutting decks must be removed and it is highly recommended that the tractor be lowered to a minimum of 3” ground clearance. The mower can be lower if preferred.

• A battery must be securely fastened to the tractor and the positive terminal must be covered with some sort of dielectric protector. No bungee cords. Industrial zip ties may be permitted upon tech directors discretion.

2. Steering:

• Factory or custom steering with steering wheel is accepted within the tech director’s discretion.

• The steering wheel must be steel/aluminum, Plastic steering wheels will not be accepted.

• Direct steering is optional with steering wheel style steering.

• Handlebars are optional (although they are highly recommended due to increased handling abilities) and must be paired with a direct steering system.

• Steering shafts, arms and bars must not be less than ½” as anything less has a strong chance of twisting/bending under load.

• Kingpins must be no less than ⅝” and spindles have to be ¾’ or above.

• Heim joints are mandatory on all steering linkages, a minimum of ⅜” but ½’ is recommended especially with the use of Hoosier tires.

• Spindles must have a “failproof” lock so wheels can not fall off during racing (Crown nut with cotter pin is a common method used).

3. Wheels and tires:

• Turf tires are mandatory in all classes.

• Hoosier tires are optional in the super mod class only.

• Front rims 6” rear rims 8’’.

• Front rims and tires can be mounted on a bearing style rim that slides directly on a spindle, or a bolt-on rim to a bearing hub is a more preferred method as it increases the rigidity of the rim. 

• Stock lawn tractor rims with plastic or brass bushing will not be accepted in this class. As well as cutting tires will not be accepted.

• Golf cart steel rims are accepted although aluminum bolt-on style rims are preferred.

4. Drivetrain and Engine:

• The engine must be of lawn tractor origin. Twin-cylinder gasoline-powered air-cooled engines are a must; no liquid-cooled type engines. Oil coolers are permitted.

• Engine modifications are open in this class.

• A tether-style kill switch is mandatory to shut the machine off in case of a rollover.

• Belt or chain drive systems allowed; centrifugal clutch or direct clutch allowed.

• Any belt/chain drive systems must be sufficiently covered with a minimum ⅛” steel or aluminum to protect the driver and other racers.

• Engine must be governed at 4000rpm if a steel flywheel is used.

•  The governor can be removed with the installation of a certified aluminum flywheel. 

• Rear hydraulic brakes are mandatory and must be mounted to the rear axle. The brakes MUST lock up.

• The rear axle is to be made of a minimum 1” shafting, mounted to the body with pillar block style bearings.

• Spring return throttle is mandatory, either on the footboard as an accelerator pedal or can be mounted on the handlebars (ATV style throttle).

• Mufflers are optional but exhaust must be safely routed out from under the hood and in a safe location (ie: under the running board, directly under the chassis, or out the back of the chassis).

• Damaged shafting can not be fixed and must be replaced

• Axles can be widened up to 42” both front and rear.