Junior Prepared Class

For Ages 9 – 15


Junior Prepared. Class designation: JP 9 year olds will only be allowed to race at CMRA club races.  USLMRA only allows 10 years and above to race at national events.


This is a highly regulated class that is specific to the modifications that are done. The intent is to have as nearly identical mowers as possible so that Junior Prepared Drivers can gain experience and develop skills needed to advance to the “Prepared Class” when they become of age.


Special requirements:

a. All JP drivers 9-15 years old must be current members of USLMRA

b. Parents/ legal guardian must be present

c. Parents/ legal guardian must be available to work corners or in the infield if needed during JP Race


1) TYPE: Must be a full-size lawn tractor, front engine, stamped steel frame and manufactured as such, as delivered except for the modifications listed below. Mid engine frames are not allowed


2) ENGINE: Governed engines, 3650 RPM max. (No Load). Single-cylinder valve-in block engines, not to exceed factory rating of 15 horsepower. Engines must be stock and complete. After market consumable parts such as

air filters and spark plugs may be used as long as they are a direct stock replacement.


3) Exhaust design is open, but must terminate away from driver and competitors, in a rearward and/or downward direction and present no apparent safety hazard.


4) Driveline:. Transmission or Transaxle must be shift able and of Lawnmower origin and gear ratio in highest gear is to be no less than 8 to1. Example: while in the highest gear the rear wheels can turn no more than one revolution every time the engine rotates eight times. No Veri-Drives, No centrifugal and or torque converter clutches. Mowers using a chain drive type transmission must use an axle-mounted brake system.


5) Body: Must be stock, without external alterations, although discrete strengthening is allowed. Hood must be secured. Also Hoods must be hinged or a hole in grill for access to spark plug wire for “RPM” checks. Minimum 4” ground clearance to frame, 2 ” from the ground to the bottom of deck. Footholds must be discrete, and no more than 2” high, made of flat or “L” stock (no rod stock), and made such that the foot can not become entangled in a rollover.


6) Deck: Mowers must mount steel factory decks. The deck must be at least as wide as either running boards or body edge whichever is wider. Decks may not extend any more than 2” beyond the tire sidewalls on each side. Deck halves may be mounted to running boards. Decks must be secure.


7) Front and rear axles must remain in stock location. Front spindles are to be min. 5/8” in diameter. All steering linkages must use ball-type or spherical threaded rod ends. Shaft locks, center drilled axle with locking bolts and castellated nuts with

cotter pins are acceptable for securing front wheels. Rear axle should use shaft locks, center bolts, or thru-bolts to secure the rear wheels. Cotter pins, E-rings, and C- rings alone, bent nails, hitch pins, over-center pins, and quick-release pins are not sufficient for wheel retention and are not approved. Rear axle may use open differential, locked, “live” or solid axle. No single wheel drive.


8) Steering; Front axle and steering may be reinforced, substituted or fabricated. In the Case of racer-fabricated axles, these will be subject to the judgment of the Technical Inspector as to their apparent safety for racing.

Aluminum may not be used as the material for the one-piece axle.


9) Wheelbase; Minimum 39" unaltered. Width; Maximum 38” sidewall to sidewall. 10) Wheels:. Metal rims 5” minimum front wheels, 8” minimum rear wheels. Rear tires maximum is 16” diameter as written on the side wall of the tire.

Actual Diameter may not exceed 16 1/4" Maximum 15 PSI tire pressure


11) Kill Switch: Mowers must be equipped with an automatic throttle-closing device. All mowers must be equipped with a kill switch, which will turn off the ignition if the driver leaves the mower. Velcro is not acceptable. Pressure switches are not

allowed. Kill switch must remain in closed position (engine not running) until driver mounts mower. Additional Switches that can by-pass the kill switch are not allowed under any circumstance.



INTENT: To provide a safe opportunity to demonstrate the driver’s ability when in competition with essentially identical mowers. This is a highly regulated class to insure uniformity between JP machines. As you can see, these machines are

essentially Prepared Chassis’ (AP, SP, CP, & BP) with IMOW drive trains. This allows young racers to gain race experience at IMOW speeds, which will approximately reach 15-20 mph (on a USLMRA US Points Track), but with a more stable platform that can easily be upgraded into the prepared classes when the driver reaches the Minimum age.