GLENWOOD HIGH SCHOOL
Gordon Murray Downhill Challenge
DESIGN AND SAFETY RULES
1. APPLICATION OF RULES
The rules and regulations are intended, as far as reasonably possible, to ensure the safety
of competitors and spectators. They must therefore be interpreted in that spirit
These rules and regulations have been selected to ensure equal opportunity to all
entrants, while allowing individual ideas for style and construction.
We encourage the spirit of "fair play" while competing in a safe and entertaining manner.
All drivers, pit crews and their families shall conduct themselves in a sportsmanlike
In all matters relating to these rules the decisions of scrutinizers and event organizers will
This is GRAVITY racing. Devices which use any form of stored energy for propulsion,
whether that energy be stored prior to or during the run, are not allowed. No other form of
motive power is allowed.
2. MANDATORY DIMENSIONS AND WEIGHT
All karts must meet the mandatory official dimensions or they will not be allowed to race.
Care must be taken to keep the center of gravity as low as possible.
Maximum overall length - 2500mm
Maximum overall width - 1200mm
Minimum track width - 700mm
Minimum ground clearance - 70mm
Maximum ground clearance - 350 mm
Maximum weight of kart and driver - 160kg
Minimum wheel outer diameter - 150mm
The track is the measured width between centres of tyres where they contact the ground.
The track may be different on front and rear axles, but both must conform to the minimum
Competitors may be randomly weighed in their race kart, complete with all their
racing/driving gear immediately before and after a race.
It is the responsibility of the driver to ensure that the weight of their kart does not change
during the course of the event.
Karts must have at least 4 wheels.
Minimum wheel outer diameter - 150mm
The wheels must all remain in contact with the ground during normal running.
The wheels must be fixed to a minimum of two axles, or when stub axles are used these
must be employed in opposed pairs.
Tires must be in good condition with no visible cracks in the sidewall or tread.
Wheels must be secured via locking nuts, double nuts, cotter pins, or other suitable
Wheels must not bind or rub anywhere throughout movement extremes.
The kart must have braking on at least 2 wheels on the same axle.
The brakes must be capable of holding the kart on a dry 30o surface when laden with
Scrub brakes may be used but must not act on the road surface.
The brakes should be designed such that they can be operated effectively while keeping
both hands on the steering control.
The steering must not be overly sensitive, have excessive free play, or any characteristic
tending to promote instability.
There must be some form of mechanical linkage or gearing in the steering so that large
inputs produce relatively small steering outputs. Steering ratios that are less than one will
not be acceptable.
Steering must be by wheel; circular or similar design, but not a T‐bar and must be fastened
to a steel shaft. If cable is used, it must be of the marine/aircraft type.
Steering mechanisms must have secure, bolted mounts.
“Rope and plank” steering is not allowed.
“Feet on the front axle” steering is not allowed.
“Lean” steering (e.g. skateboard) is not allowed.
Differential braking or “skid” steering is not allowed.
Steering wheel design does not present a potential hazard to the driver.
6. DRIVING POSITION
The driver will ride alone, feet first.
Only seated, reclined or supine (Lying on the back with the face up) driving positions are
Prone (Lying on the front with the face down) or head first driving positions are not
7. BODYWORK AND SAFETY FEATURES
Bodywork (Both Divisions)
All karts are to have bodywork including a footboard, enclosing the driver’s legs.
Bodywork must extend at least 150mm past the driver’s feet.
No glass or other materials that would shatter or cause injuries to drivers and spectators in
the event of a crash can be used in the construction of the kart.
There must be no sharp edges or protrusions either inside or outside the kart.
Any steering column, brake lever or other protrusion must be designed and fitted such that
puncture injuries cannot occur.
Bodywork and controls must not impede the driver in exiting the kart unaided.
Any doors or hatches required for driver access must be readily operated from both inside
and outside the kart without the use of tools.
Handles, latches, etc. for access points must be clearly marked.
Bodywork (Division 1: Schools specifications)
All bodywork is to be constructed of wood except for: Steering mechanism, axle mounts,
braking mechanism and roll bar.
Brackets used to secure the steering mechanism, axles, braking mechanism and roll bar,
may not extend more than 100mm forward or behind the structure secured.
No form of metal chassis support will be allowed.
Karts will be checked for concealed use of banned materials.
A floorboard must be constructed of solid plank or plywood and have a minimum of 18mm
The exterior of the kart may be finished in paint but the interior should be left unpainted or
finished with a clear sealant.
Bodywork (Division 2: Open specifications)
There are no restrictions on the type of materials used except for the hazardous materials
The following safety devices must be fitted and used:
A substantial roll-over bar above or to the rear of the driver’s head. It shall be in a suitable
position to protect the head, neck and spine of the driver should the kart become inverted
or topple on to its side.
The top most points of the roll-over bars shall be at least 50mm above the helmet of the
driver when he/she is seated normally in the kart.
An impact resistant structure at least 150mm forward of the driver’s feet which is sufficient
to offer protection to the driver in the event of a head-on collision.
The driver must have good all round vision, including to both sides and the rear. At least
one functional rear view mirror is required.
A car-standard harness with a minimum two-point fixing to the kart floorboard or frame
Ballast/Weights must be inside the kart, securely mounted directly to the floorboards by a
bolt, lock washer and nut.
The driver may not carry any ballast on their person.
8. SAFETY WEAR (Personal Protective Equipment)
The driver’s body and limbs must be fully covered by suitable abrasion resistant clothing
such as; heavy duty overalls, a karting suit or, ideally, motorcycle leathers or similar.
For the avoidance of doubt, skateboard helmets, mountain bike helmets, cycle helmets,
riding hats, etc are not acceptable. Only proper motorsport/motorcycle helmets are
If the helmet is “open-face” a shatterproof visor or goggles must be worn.
The helmet must be in good condition and worn to the manufacturers recommendations.
The helmet strap must be worn tight and secure as designed.
The driver must wear a helmet at all times when competing.
The driver must wear full fingered abrasion resistant gloves.
Shoes must be in good condition and be laced, buckled or secured as designed. The
ankles must be protected against abrasion injuries.
ELBOW AND KNEE PADS
Protective padding for the knees and elbows is recommended but not mandatory.