Racing Divisions and Noted Rules of the ARMA

Before participating in any lawn mower racing event, you have to choose your racing division. The American Racing Mower Association has 7 divisions, ranging from novice to expert.

ARMA – Kids Stock, Adult Stock

This is the novice level using stock lawn mowers. The governor should not be removed, the wheelbase is stock, and the front and rear rims are original. In short, just remove the blades and ride it to the finish line.  It’s a great “beginners” division.

ARMA – Kids Super Stock, Adult Super Stock

A little quicker ad a little slicker, but still considered entry level lawn mower racing. You will be able to modify a few things to your racing mower.

•    A governed engine is required, but it can be 3650RPM, single cylinder OHV or VIB no more than 465cc and 15HP.
•    Full size mowers with a wheelbase of 39”
•    Front wheel should be 6” with tires ranging from 13” to 15”
•    Rear wheels should be 8” with 16” tires.
•    Tire pressure up to 15 PSI.
•    Air cleaner, air filter, and an open exhaust are allowed.
•    The frame and the inside of the rims can be reinforced for added durability.
•    The shift mechanism should be original with a maximum gear ratio of 8-1.
•    The body must be stock complete with factory deck.
•    Spindles in front must be minimum 5/8”.

ARMA – Mini Sportsman

Now it’s getting exciting. This is a lawn mower racing division for those who want to build their own racing mower from scratch.

•    There are no restrictions on internal engine modifications. (Sweet!)
•    Engines should be 4 stroke, valve in block, and not greater than 8.5HP and 19 cubic inches. (You’ll be eating dust if you use an inferior engine.)
•    The chassis should have a minimum wheelbase of 34”
•    The front and rear wheels have minimums of 4” and 6” respectively.

ARMA – Sportsman

This division is for those who have a little lawn mower racing experience and a few racing mower stories.

•    As with the Mini-Sportsman, engines should be valve in block, single cylinder 4 stroke, but can be over 8.5HP
•    A minimum and unaltered chassis of 39”.
•    Front wheels are 5” minimum
•    Rear wheels are 6” minimum and 8” maximum.
•    No mid engine frames allowed in this division.

ARMA – Mod X

Now we are getting to the advanced divisions.

•    You get to use a more advanced single OHV and Twin Opposed VIB with under 20HP.
•    A minimum wheelbase of 39” for the chassis of you racing mower.
•    Still no mid engine frames.
•    5” minimum for the front wheels and 6” to 8” for the rear wheels.

ARMA – Super Sportsman

Just by the name of it, you’ll know that this division is something special. This is where you’ll see the fast and the furious of lawn mower racing.

•    Powerful all overhead valve, 2 cylinder, 4 stroke, and up to 25HP engines are used. Try mowing your lawn with this baby.
•    A wheelbase of 42” for the chassis
•    Stock frames
•    6” minimum for the front wheels and 6” to 8” for the rear wheels.

ARMA – Pro X

This is where the best of the best hang out. It is the dream of every lawn mower racing enthusiast to compete in this division. Ever seen a racing mower dig dirt and drift on corners?

•    Single cylinder and 4 stroke engines with no max on HP.
•    Mid engine frames are allowed.
•    A maximum chassis of 42”.
•    45” maximum for pan style frames.
•    You can shorten the wheelbase to up to 37”.
•    Front and rear wheels are 4” to 8” respectively.
•    You may use kart tires, as well as add stagger. But, no offsetting the wheels.
•    No round tubing and chrome molly tubing allowed.

Those are the 7 lawn mower racing divisions under the American Racing Mower Association. If you are new to the sport and haven’t ridden a racing mower yet, you might want to start out in the novice divisions and work your way up to the Pro X division.