The wheels bearing the weight of a land vehicle onto the ground or its own tracks.
The fitting of tracks to a tracked vehicle calls for a rather different design of road wheel, compared with its wheel-only counterpart. The modern armoured fighting vehicles use a dual wheel design. The other main difference from wheel-only vehicle wheels is the absence of a pneumatic tyre. In the case of the tank, the reason for this stems principally from the role of the vehicle, which exposes it to fire more often than the lightly armoured wheeled armoured fighting vehicles. However, additionally it is found that the size of pneumatic tyre needed to carry the loads involved would be too great to fit into the space available. As a result, solid rubber tyres are used. Even these present a design problem: as tanks get ever heavier and their road speeds increase, the tyres become liable to overheat. To minimise tyre rolling resistance, the need is for larger diameter wheels. However, in order to optimise soft ground performance, uniform weight distribution is needed, calling for a large number of wheels. The normal compromise is 6 or 7 road wheels per side on tanks, whilst smaller, lighter AFVs use 4 or 5.
Sergyi Way
18.12.2006