About the Quad Bar
The Concept
The Quad bar is a small unobtrusive, hairpin shaped hoop mounted on the quad bike behind the rider designed to counter some of the risks associated with rollovers.
The Design
The Quad Bar (51mm aluminium tube) is mounted on the tow bar and is telescopically adjustable at the base. A support mount is attached to the rear rack, where the bar passes through sliding collars (bushes), which subsequently allow the suspension to move freely. The use of the tow bar is not affected by attachment of the Quad Bar.
The Theory
Back flip
In the case of a back flip, the 2 x 45degree bends in the hoop above the tow bar come in contact with the ground first and the two rear wheels are still in contact with the ground. At this point, the bike should then return to its wheels. For the bike to completely back flip, the roll over would require considerably more force/momentum. If considerable force is involved in the back flip (ie as a result of excessive speed or very steep terrain), the bike rides or rears up on the hoop and will then return to its wheels or fall to the side. The bar should prevent a full backflip, in which the usual outcome is the operator being pinned underneath an upside down vehicle.
Sideways roll
The hoop design is important in the case of a sideways roll, as the bike will initially land on it side the same way as if there is no roll bar fitted. The Bar would then prevent the bike from completing the flip and landing upside down. A quad bike on its side is unstable and it is considerably easier to roll back onto it wheels even if the operator is in a ‘pinned’ position; than if it was upside down.
If the bar design was a full width roll bar (i.e. square) the bike would be more stable on its side and there would be a considerably increased area in point of contact with the ground, thereby increasing the chances of the operator being pinned by the bar itself. The top point of the bar is also more likely to ‘dig in’ and create a pivot point that would allow the vehicle to complete a full roll over.
A bike with the Quad Bar fitted can first land on the side and will then roll slightly further until the hoop comes into contact with the ground. Because of the shape of the Quad Bar, the bike would rather slide than complete the roll over. Also the surface area (point of contact) of the bar in contact with the ground is reduced and less likely to be responsible for pinning the operator.
Operator restraints are not warranted with this type of roll over protection, as abandoning the bike is a significant strategy of operators for injury prevention. The fact that the bar is unobtrusive i.e.does not interfere with the mounting and dismounting of the vehicle, allows the operator the opportunity to jump clear of the vehicle.
Retrofit
The quad bar is essentially a bolt on attachment. Currently 1 kit should fit most bikes that are fitted with a tow bar & rack. However some of the less popular bikes may require variations of the brackets.
Fitting is simple and could be fitted by a customer with basic mechanical skills and tools. If professional fitting is required it takes between ½ hr and 1 hour labour.
Specifications
- Hoop 51 x 3.2mm Aluminum tube
- Horizontal variance between tow bar & rack 180 – 260mm
- Overall height 1400mm
- Approximate height above seat level 700mm
- Weight 7kg
- Padding 9mm close cell UV stabilized
- Fittings laser cut for accuracy and consistency
- Fittings powder coated or zinc plated
Product Testing
Monash University in Melbourne is currently undertaking computer modelling of the Quad Bar. Sulman Forensics Toowoomba has undertaken a series of strength and destructive tests. Results of these tests will be made available on this site pending finalisation.