The ATV frame affects its dynamic and strength characteristics, and is also the supporting base for all nodes. Self-assembly begins with the study of the frame, its welding and layout. Often a motorcycle frame acts as a donor, and sometimes the master designs it from scratch.
Preparation of drawings
Assembling an ATV with your own hands begins with the preparation of drawings. They should indicate the places of attachment of the engine, suspension, seat, steering system. The metal frame must have a certain rigidity, be resistant to ultimate loads, so its design is carefully worked out on the drawings. More than one sheet of paper will be ruined until the perfect solution is found. You can take drawings of an existing ATV frame and customize them to your specifications.
As an alternative, a ready-made old motorcycle frame of the "Ural" or "IZH" type is taken. preferableuse the load-bearing elements of the Dnepr heavy motorcycle, as they are designed for heavy loads. For extreme cross-country driving conditions, it is better to use car frame parts from a small car, for example, the Oka. And if you take the frame from the scooter "Ant", the result of the assembly will not keep you waiting.
The advantage of converting factory frames from a motorcycle or small car will be the presence of its number, which is needed when registering a vehicle with the traffic police. Otherwise, the homemade ATV will not be able to be used on the roads and will require a car trailer to be transported.
Features of wireframe development
The size of the ATV frame depends on the power of the installed engine and the number of people it will carry. The optimal length is in the range of 1600-2100 mm, and the width is 1000-1300 mm. The long frame will have to be reinforced with additional rigid elements so that it does not break while riding. A frame that is too wide will experience lateral loads, but the ATV will be more stable when cornering.
Increasing the number of stiffening ribs will increase the mass, which will negatively affect the dynamic characteristics of the ATV and require the installation of a powerful engine.
For fun walks on asph alt, you can neglect the excessive rigidity of the structure, giving preference to a low-power engine. Lightweight touring ATVs for adults have small dimensions and lightweight construction, but on the framethere are more mounts to expand the functionality - installation of trunks.
Selection of materials
Most often, a round-section seam steel pipe is used to make an ATV frame. This pipe is suitable for light structures that are not designed for high loads. Round pipes are bent by a conventional pipe bending machine, so the number of welded joints will be minimal. For welding a frame designed for an adult, pipes with a diameter of 20-25 mm with a wall thickness of 1-3 mm will suffice.
Pipes with a profile section - a square or a rectangle - have a large tensile strength. It is much more difficult to bend a metal profile; special skills and equipment will be required. For stiffeners, engine mounting points and steering parts, as well as brackets, metal sheets with a thickness of 3-5 mm are suitable, depending on the required mass and rigidity of the frame.
Before assembly, spot welding of the structural components is carried out, and only after checking the symmetry and dimensions, they begin to weld the seams.
The most difficult part of making an ATV frame will be welding and assembling the steering. The steering column must be firmly attached to the frame, being its integral part. It is best to use a ready-made steering wheel from a motorcycle, on which levers with silent blocks are hung. Since the steering is subjected to constant shock loads when hitting bumps and pits, additional stiffeners will not become superfluous.
The advantage of installing prefabricated parts is to use accurate factory parts, while making them yourself can lead to errors in dimensions. Minor deviations from symmetry will cause the ATV to become uncontrollable at high speeds or when riding aggressively. For welding the front part of the frame, profiled pipes are used, their bending strength is higher.
Finishing attachment points
All other parts are attached to the ATV frame, so the frame must be equipped with a sufficient number of knot attachment points. The frame houses the engine, steering, brake system, transmission, front and rear suspensions, body. After installing the main components, you will need to choose a place for laying electrical wiring, installing a silencer, gas tank, headlights, seats, trunk. On a 4x4 ATV frame, the number of mounting points will increase due to the increased complexity of the transmission design.