The artillery wheel was eveloped for use on gun carriages when it was found that the lateral forces involved in horse artillery manoeuvres caused normally-constructed cart wheels to collapse. Rather than having its spokes mortised into a wooden nave (hub), it has them fitted together (mitred) then bolted into a metal nave. Its tyre is shrunk onto the rim in the usual way but it is also bolted on for security. A normal wagon wheel is dished so that in its lowest part, the spokes are vertical but in its top part, they are angled outwards to clear the body of the vehicle. This is not done with artillery wheels.