USLMRA J/P (Junior Prepared) 12 – 16 

INtruducing a racing class for ages under 16, JP is now available at the national competition level, a set of build rules, patterned after successful club race rules, has been formulated.  This supplement is being made available to local clubs and their racers in the hope that at a future time, the Association and machines that already fit the rules criteria, and with race experience at the club level. 12-16 year old racing class “Junior Prepared”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 this class is based on driving ability.

 

1) TYPE: Must be a full-size lawn tractor, 39” minimum unaltered wheelbase, front engine, steering column behind motor, stamped steel frame and manufactured as such, as delivered except for the modifications listed below. 

 

2) ENGINE: Governed engines, 3650 RPM max. (No Load). Single-cylinder valve-in-block (flathead) engines 15 horsepower and under. 

 

3) DRIVELINE: Transmission or Transaxle must be shift able and of lawnmower origin and gear ratio in highest gear is to be 9 to 1. Example: While in the highest gear, the rear wheels can turn no more than one revolution every time the engine rotates nine times. 

 

4) Body: Must be stock, without external alterations. Hood must be secured. 

 

5) FRAME: Discrete strengthening is allowed, front spindles min. 5/8” diameter. Front axle may be reinforced, substituted or fabricated. In the case of racer-fabricated axles, these will be subject to the judgments of the Technical Inspector as to their apparent safety for racing. Aluminum may not be used as the material for the one-piece axle. Machine may be widened to 38” max and lowered to the 4” frame, 2.5” deck limits. 

 

6) Wheels: Metal rims 6” diameter. Front, 8” diameter. Rear. Tires 13” diameter. Front, 16” diameter. Rear. Rims may be reinforced on the inside (back) only. 

 

7) Deck: Mowers must mount steel factory decks. The deck must either be at least as wide as 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. 

 

8) 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. Lanyard shall be no longer than 40 inches, tip to tip in stretched out length. Additional Switches that can by-pass the kill switch are not allowed under any circumstance.

 

 The ignition interrupter kill switch and cap/prong must be commercially available for racing type vehicles such as jet skis, snowmobiles, 4-wheelers etc. Magnetic or any other form of homemade switch is not allowed. 

 

9) Modifications not listed are not approved. 

 

10) Intent:

As you can see, these machines are essentially Prepared Chassis’ with IMOW drive trains. This allows young racers to gain race experience at IMOW speeds, but with a more stable platform that can easily be upgraded into the Prepared classes when the driver reaches the Minimum age.