The Quad (or ATV—all terrain vehicle) was created as a more stable 4 wheel version of the original ATC (All-terrain cycle) or trike three-wheeler. It is a bike-type off-road machine that has been used primarily in off-road dirt-type racing. It has also been used in oval dirt and in paved track racing and fits, despite its handle bar controls and saddle seat, the definition a small race car.
Quads are characterized today by a tube frame chassis, mid-engine and rear or four wheel drive. They utilize treaded, knobby, and even slick type tires mounted to an independent front and swingarm solid-axle rear suspension (usually). For off-road racing, the suspension is long-travel to enables the vehicle to travel over very rough terrain and jumps. For oval or pavement type racing the suspension has less travel and the chassis is lowered.
Racing events are held on desert, wooded, and other natural terrain as well as dirt ovals and paved tracks. Racing is held in many parts of the world.
|Power and Weight Stats|
|Horsepower (Typical Range)||25-65|
|Race Weight (Typical Range)||249-295 kg
Design and Construction
Race Car Models of This Type
Numerous models of Quad are built by the manufacturers Honda, Kawasaki, Suzuki, Yamaha, Arctic Cat among others.
Build Your Own Quad/ATV
Building a quad can be approached in two ways: Customizing an existing model of Quad or building a brand new design from scratch.
If you opt to customize an existing quad through aftermarket components, it is recommended you have a good working knowledge of handling, chassis, suspension, and powertrain. Being able to understand the effects of modifications will enable you to choose the areas and components that provide the results you are looking for.
If you want to build a new quad design, then scratch-building will be the approach to take. You should be knowledgeable in handling, chassis, suspension, powertrain, and aerodynamic design. These five major areas of the quad design work as an integrated unit and the designer must have an understanding of how changes to one area affect the others. Design work is iterative, meaning re-designing areas based on new changes to another area. After the iterations are completed, the design will be complete and optimized.
Because of the varied environments where Quads can operate, knowledge of the terrain is important to ensure the vehicle will handle the demands of the surface and speed.
Suspension: Maximizing the contact patch of the tires with good suspension geometry is of key importance. Because of the long suspension travel there can be significant camber change. Some camber may be of benefit in cornering, but excessive camber will likely mean less traction.
Suspension, wheel and tire weights (Unsprung weight) affect the compliance of the suspension, which in turn affects handling, so keeping all these components as light as possible is an advantage. Springs and dampers (shock absorber) must be matched to the forces you expect the suspension to handle.
The suspension pickup point locations impact the chassis design.
Chassis: Providing openings to make internal components accessible for maintenance is important. If scratch-building the engine fit and mounts should be considered after determining the suspension/handling goals. Iterations may be required to match handling goals and engine positioning.
Aerodynamic: Unless raced at speeds above 60 mph, the aerodynamic effects will likely be secondary to handling and driving.
Safety: Consideration should be given to scenarios the Quad may encounter (ie. Roll-over, collision, etc) and protection added where the risk is sufficient.
If you intend to race under a sanctioning body, always read and understand the regulations of your chosen racing class before designing or building any race vehicle.
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If you are customizing an existing quad, the project will primarily involve replacement of stock parts.
If you are building from scratch, then ensuring the chassis is dimensionally accurate and straight is important as flaws in the structure will create handling issues via misaligned suspension. The use of a solid, flat and level build space is important. Jigs are often used in this case to ensure that structural tubing stays in alignment during welding/brazing.
The builder should have solid joining and metal working knowledge and skills when fabricating the chassis/rollcage/suspension. While mild steel (1018/1020) is very forgiving, some metals are best welded using a specific method (mig/tig) and some require heat treatments before and following welding to restore their toughness and strength.
Having sufficient space for the chassis and body panel construction is important, as a cramped workshop can be difficult to work in. However, in the case of a quad, a small garage will likely suffice.
Many components for customizing a stock Quad/ATV can be sourced from existing Quad/ATV manufacturers or the aftermarket. Depending on how many modifications are made, the costs can reach the equivalent of the original Quad price or higher.
If you are constructing from scratch, the variety of available options becomes huge. You can pick and choose the ideal suspension and engine components from any manufacturer. Your job is then to integrate these components into a cohesive package.
If the Quad/ATV is to be used in racing, there will likely be a high standard of quality required. The costs may be significantly more than for someone who wants to zip around their back yard. Costs for a race quality machine usually include higher quality suspension, engine and safety components.
If you are customizing from a base quad, the effort will be around stock component upgrades. The time and effort depends on the complexity of the changes, but many upgrades can be weekend projects.
If you are scratch-building there will be significant effort in design and construction. There is however, an equally great satisfaction and sense of accomplishment at being one of the few people in the world who have built their own quad from the ground up!
Consumable costs depend on the seriousness of the racing—Tires probably form the single largest consumable expense along with engine rebuilds and suspension part replacements. A dirty or gritty working environment will usually translate into parts wearing out sooner.
Transportation and Support Equipment