The shape of a snowboard is dictated mainly by what it's going to be used for. Twintip boards tend to be more suited to park and pipe riding as they have the same geometry whether riding forwards or fakie. But for those deep powder days it's better to ride a board with a setback stance and a longer (and possibly wider) nose than tail. This configuration aids flotation and reduces the stress on your back leg as you try to keep the nose from tucking under. Or you might want an all-out race board, with the longest possible effective edge and a progressive sidecut for aggressive carved turns.
^ Alpine, Twintip, Directional and Swallowtail shapes
| Parameter Name | Description |
|---|---|
| Running Length | The distance along the central axis between the front and rear contact points of the base with the snow |
| Sidecut Radius | The degree of waisting of the board expressed as the radius of the circle forming the arc of the sidecut. This is in practice often implemented as a blend of multiple sidecuts or as a quadratic function. Doing the former enables more predictable turn entry and exit behaviour. The latter creates smooth transitions from turn entry to exit, with a benign entry and a more aggressive hold and exit phase. In both of these cases the radius at the nose is usually larger than that at the tail |
| Nose and Tail Length | The length of the material forming the nose / tail of the board - beyond the running length |
| Nose and Tail Width | The distance measured across the widest part of the nose or tail |
| Stance Width | The distance from the centre of the front insert pack to the centre of the rear insert pack |
| Stance Offset / Setback | The distance to which the stance is set back from the centre |
| Effective Edge | The distance along the sidecut between the widest point of the nose and the widest point of the tail |
The longitudinal flex pattern of the board is a description of where the board becomes stiffer or more flexible along its length. This determines how the board will ride, and is one of the trickiest and most important things to get right.
The correct flex for a board depends very much upon the rider and the type of riding he or she wants to do with it. Generally speaking, the more aggressively and and the faster you ride, the stiffer the board should be. Stiff boards offer stability at speed and a stable platform for long carved turns. Softer flexes can be applied for jibbing boards - for buttering tricks - it makes nose presses easier - and also for powder boards where a softer nose can help keep the tip above the snow surface and absorb impacts.
But there's more to it. Freestylers who ride pipe need a board soft enough to flex into the transitions and to land off-balance and absorb the mistakes. But you also need to retain some stiffness or 'snap' in the tail to increase the strength for landing airs, and to add more spring for launching ollies.
^ Thickness affects flex : Red indicates stiffer flex, yellow softer flex
In the diagram above we can see how a snowboard longitudinal flex is governed by thickness of the core. The example shows a board with an optionally softer section between the riders feet - this is not always required, but it gives a more playful feel to the board and helps it bend smoothly during turns. The dimensions shown are an example only and are roughly appropriate to a medium flex 160-ish sized board.
The second critical type of flex we need to control is the torsional flex - the amount a snowboard can twist. As with longitudinal flex, we want certain parts of the board to twist more than others. For example, when putting the board on edge we need to transmit force from the riders feet the the contact points of the board. This is done efficiently if the board does not twist too much between the feet and the contact point - optimum power transfer. But we want to be able to control the board when transitioning from one turn direction to the other, and to be able to initiate turns by deliberately twisting the board. We can do this by making the board torsionally softer between the feet.
^ Torsional Flex : Stiffness from the riders feet to the contact points
Torsional flex is mainly controlled by the materials used in the board. Strategic use of stiffer fibres - either a uniform tri-axial glassfibre with +/- 45' fibres, or strips of reinforcement - carbon or glass - placed along the axis where stiffness is required - eg the black arrows in the above diagram.
Camber refers to the curved nature of the 'contact area' of the board - the bit that runs on the snow between the upcurved tip and tail sections. The camber is there to increase the speed of return of the board from the concave flex of a turn to the more or less flat flex of regular cruising.
When the board is on edge and turning, the sidecut forces the riders weight to push the board against its naturally cambered shape into one of 'negative' camber. The more camber you have to overcome, the more force you need to apply to get the board to carve. Then on exiting the turn, the board has a natural desire to pop back into its cambered shape assisting you and increasing the edge to edge response of the board. It's a complex issue and getting the balance of sidecut, flex and camber has a lot to do with getting the ride right.
Our mould is built with a 20mm camber, taking into account the fact that after demoulding the board will 'relax' and lose some of the original camber. We aim for an average mid-life camber of 10-15mm.Then while riding, the camber will gradually break down under structural fatigue - when the camber has gone many riders feel their board has lost its 'pop' or liveliness.
Snowboards consist of a number of individual components bonded together to form a light strong composite structure. All snowboards are sandwich structures
^ Breakdown of the layers of the sandwich
The core is the filling of the sandwich, and needs to be fully enclosed by the other components, to protect it from water contamination and abuse. A sidewall design uses plastic strips bonded to the side of the core to protect it from the elements. This requires more material and manufacturing steps, but can be easier for homebuilders to deal with. Cap construction has a chamfered edge to the core, and the top reinforcement and topsheet wrap around the taper and meet the base.
^ Sidewall Construction
^ Cap Construction