United States Lawn Mower Racing Association
It all began on April Fools day in 1992. Executives of Chicago-based Gold Eagle Co. makers
of STA-BIL® Fuel Stabilizer, brought lawn mower racing to the United States after visiting our friends
with the British Lawn Mower Association in England.
They thought lawn mower racing would be an interesting product promotion for STA-BIL Fuel Stabilizer.
Since then, the STA-BIL Nationals has grown from one race to more than 20 STA-BIL Regional and STA-BIL Mowdown races across the country.
It all began on April Fools day in 1992. Executives of Chicago-based Gold Eagle Co. makers of STA-BIL® Fuel Stabilizer, brought lawn mower racing to the United States after visiting our friends with the British Lawn Mower Association in England.
They thought lawn mower racing would be an interesting product promotion for STA-BIL Fuel Stabilizer.
Since then, the STA-BIL Nationals has grown from one race to more than 20 STA-BIL Regional and STA-BIL Mowdown races across the country.
Overview of USLMRA Racing Classes:
(See USLMRA Rulebook at www.letsmow.com for Complete Rules)
IMOW:
This is a highly regulated class class. The intent is to have as nearly identical mowers as possible so that this class is based on driving ability. Must be a full-size lawn tractor, front engine, steering column behind motor, stamped steel frame and manufactured as such, as delivered except for the modifications listed below. Mid engine frames are not allowed. Governed engines, 3640 RPM max. (No Load). Single-cylinder, valve-in-block highest gear is to be no less than 8 to 1. Example: While in the highest gear the rear wheels can turn no more than one revolution every time the engine rotates 8 times. No Veri-drives.
Prepared Classes:
Full bodied mowers with allowed modifications and engine size rules. Engines can be modified.
A/P:
8 1/2 hp limit. Usually older mowers that came with engines under 8 1/2 hp.
C/P:
all single-cylinder overhead valve and two cylinder valve in block, 4 stroke engines, 20 hp and under. 42″mi unaltered wheelbase. Mid engine frames are not allowed. 6″ minimum front wheels. 8″ minimum rear wheels.
S/P:
12 hp Flat Head engine limit. Your more common late model lawn mowers.
B/P:
Over 12 hp OHV single CYL, and up to 20 hp block V-twin CYL engines. This class sounds like a pack of Harleys. The V-twins can be built to over 40 hp with aftermarket engine parts. They have lots of power, but are big, heavy and a handful to drive. Fast and loud.
F/X:
Factory Experimental. Engine limited to a single CYL up to 465cc (12-14 hp). Must be a mower engine. Lots of modifications allowed. Trans-Drive train open. This class, while restricted power-wise, is usually light and fast. It can have a kart clutch or torque converter drive systems.