STOCK MOWER - a lawn mower, which has had no modifications to the engine. Governed engines, 3650 RPM max. (No load)

Modified Classes

​​​​​​​Class 1 Modified Mower Engines originally manufactured for lawnmowers, up to 28ci flat head single cylinder.Allows internal and external modification, but limits to external modification are: you must retain factory intact manifold and a single barrel lawnmower carb. 

Class 2 Modified MowerEngines originally manufactured for lawnmowers, up to 32 ci single or twin cylinder.Engine may be internally and externally modified.

Class 3 Modified MowerEngines originally manufactured for lawnmowers, up to and over 32 ci single or twin cylinder.Engine may be internally and externally modified.

General Rules For Racing MowersThe intention (or spirit) of the rules is that racing mowers must retain the appearance of a ride on lawnmower and incorporate the hood, bulkhead and metal steering support structure, as well as rear body and rear guards. The mowers can be lowered and discrete modifications made to original chassis to allow fitment of brakes, gearboxes etc. Similarly ride-on mowers style bodywork must be used but can be discretely modified to fit wheels, exhausts, seat positions etc. Rear wheels must be larger diameter than the front wheel. See chassis and wheels below.  The NZLMRA committee is the judge of fact to the issue of appearance.

Driveline: Driveline may be modified from the engine pulley to the rear wheels, but must utilize a lawnmower transmission, transaxle or right angle drive.As long as it is a standard factory or direct bolt in after market ride on mower gearbox it is acceptable.If a gearbox is built using ride on lawn mower gear box parts, axles and gears this is also acceptable RAGBS that are not acceptable are fertiliser spreaders, tractor mowers, large commercial mowers or other commercial application gearboxes

Engine must be within 100mm of the original location

Induction No forced induction, No supercharging, no turbo charging, no Nitrous oxide

Rear axle may use open differential, locked, “live” or solid axle. No single wheel drive. Must use at least one drive belt.Rear axle should use shaft locks, centre bolts, or thru-bolts to secure the rear wheels. Maximum diameter 25.4mm (1").

Clutches: All mowers must have an operating clutch. Centrifugal and or torque converter clutches not recommended.

Brakes: Must use axle mounted brakes, no lawnmower transaxle or transmission mounted brakes. No front brakes.

Steering: All steering linkages must use ball-type or spherical threaded rod ends.  Kingpins and wheel bearings to be serviceable

Front axle must be pinned, bolted or welded. No suspension, no shock absorbers. Axles must have a 1-piece beam.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.Aluminium may not be used as the material for the one piece axle.

Front Wheels: Shaft locks, centre-drilled axle with locking bolts, castellated nuts with cotter pins, are acceptable for securing front wheels. E-rings and C-rings alone, bent nails, hitch pins, over-centre pins and quick-release pins are not sufficient for wheel retention and are not approved.

Body: Hoods and body parts such as fenders, rear body or rear guards may be upgraded and mudguards may be discreetly moved and altered however, as far as practical 100% of the original body components must be retained. All mowers must have a hood, chassis and floor, bulkhead or recognisable mower dash console and metal steering support structure, as well as rear body and rear guards. The objective is to retain the appearance of a ride-on lawnmower by using ride-on mower style bodywork.

Chassis:  A mower must, as far as practical, incorporate 100% of the original lawnmower chassis. Limited modification of the original chassis is permitted. Discrete strengthening and modifications can be made to the original chassis to allow fitment of brakes, gearboxes, stiffening and the like. Modification can include the lengthening, cutting or adapting the chassis where practical and safe. The installation of braces or other components to strengthen the original chassis or body is permitted. Where any portion of the chassis is replaced during the course of any modification the same quality of material should be used. Space frame type chassis is specifically prohibited. The objective is to retain the appearance of a ride-on lawnmower.

Front BumpersAre not compulsory, but recommended with a centre impact zone of 150mm from the ground and a maximum width of 650mm with some flexibility to design within the recommended measurements

Rear BumpersCompulsory, recommended with a centre impact zone of 150mm from the ground, minimum width of 900mm and maximum width of 980mm.Rear bumpers may not be a single straight pipe, must have rear wheel protection area, minimum 120mm and maximum 180mm in height as per designs on spec sheet.All bumpers to have rounded edges.  No sharp protrusions or bolts. 

Controls: Throttle controls may be relocated. Throttle must return to idle when released. All mowers must have brake controls fitted to either the steering wheel or foot area and be easily activated at all times.  The throttle must have two return springs fitted to separate locations.

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

Starter: Starter must be onboard, either electric or pull-rope.

Overall Width: The maximum width of any mower shall be 1.0 metre (39.4”) at the widest point.

Footholds: Footholds must be discrete, and no more than 50 mm (2”) high, made of flat or “L” stock (no rod stock), and made such that the foot cannot become entangled in a rollover.

Blades or Cutters: All mowers shall have the blades or cutters removed.

Battery: All positively charged terminals must be insulated with a cover or heavy tape, and the battery must be well secured.

Cut off switch: All participating mowers shall be fitted with an operational cut off switch of an approved type which is connected to the driver by means of a lanyard. Electric fuel pumps must be deactivated with removal of the cut-off lanyard

Flywheels: Factory flywheels must remain stock. No modifications including lightening, removal of fins or alternator magnets is permitted.

Alloy Fly Wheels are allowed in class 1 modified, class 2 & class 3 but are not compulsory.Alloy fly wheels are recommended on engines that have had internal performance modifications.

Sharp or dangerous protrusions: Mowers, which have sharp or dangerous protrusions, shall be deemed ineligible for participation. Glass headlights must be taped or removed. No axle or wheel mounting bolts may protrude beyond the face of the tyre sidewall.

Safety: Mowers must be safe and complete, all parts and panels in place, with no missing nuts, bolts, cotter keys, etc.All exposed chains and sprockets must be fitted with metal guards, which will direct a broken chain downward.Steering wheels only, no protruding bars.

Mowers must be neat and clean, with paint in new or very good condition. No excess dirt, oil, grease, rust or primer. Sponsor graphics must not interfere with mower’s racing numbers or class letters.

Rear wheels must be the same size on each axle, made of metal, minimum 8”, maximum 10” diameter. Rear axle should use shaft locks, centre bolts or thru-bolts to secure rear wheels. No dual or tandem wheels.Front wheels must be same diameter, made of metal. The front wheel rim diameter must be at least two inches less than the rear wheel rim diameter. The objective is to retain the appearance of a ride-on lawnmower.

Ride height: Lowering is recommended.

Seat: The driver’s seat must be of reasonable strength and not impede the drivers exit. Automotive or race car type seats are not recommended.

Tyres: Tyres, which are fitted to any competition mower, must comply with the following—1. Agricultural or flotation type ATV tyres are prohibited2. Speed rated radial tyres as used on racing ATVs can to be used on front3. Both tubeless or tube type tyres can be used unless prohibited by organisers4. The use of knobbly tyres or smooth pattern tyres on the drive wheels will depend on the ruling by event organisers.Rear tyres may not be modified in any way.  No cutting re re-grooving.

Race numbers: Every mower shall be issued with a race number, which is assigned by the Secretary of the Association. Race numbers shall be displayed on the side or rear of all mowers, be around 150 mm in height and width and a contrasting colour to the mower.

Subsequent technical inspection requirement: Any mower deemed ineligible for participation due to sharp or dangerous protrusions or that is involved in an incident causing accidental damage during a race must be re-inspected by the Technical Inspector and approved.

Grandfather Rule:  All mowers that are currently racing with be able to continue to race under the new rules, however they cannot be sold after 31 December 2013 as a legal racing lawnmower.  If the mower is altered in any way then it must be brought into line with the new regulations.  All mowers must be compliant before 31 December 2015.

Compliance: After a two year period of time to allow people to bring their mowers into line with rule and regulations, which have being set and voted on by all the clubs in the association to create a level set of rules and guide lines for mower racing in NZ. It is expected that all clubs strive to comply. To meet our obligations under the Health and Safety act. Also for our insurance to be valid.