Sliding pillar

A sliding pillar suspension is one in which the stub axle and wheel assembly are attached to a fixed vertical "pillar" or kingpin which slides up and down through a bush or bushes which are attached to the vehicle chassis, usually as part of transverse outrigger assemblies.

Sliding pillar independent suspension was first used by Decauville in 1898, the first recorded instance of independent front suspension on a motor vehicle. In this system, the stub axle carrying the wheel was fixed to the bottom of a pillar which slid up and down through a bush in a transverse axle member fixed to the front of the chassis. The top of the pillar was fixed and pivotted on a transverse semi-elliptic spring. This system was copied by Sizaire-Naudin a few years later.

In around 1904, the New Jersey inventor, J. Walter Christie introduced a sliding pillar suspension system with vertical coil springs, which would appear to be the inspiration for that used by Lancia on its Lambda from around 1922 on. In turn, this was copied by Nash for its 600 model for one year, perhaps because each of these cars was the first in its country constructed using the very light unibody technique.

Sliding pillar suspension systems have also been used by several cyclecar manufacturers, the French maker Tracta, and in several prototype vehicles.

In 1909 HFS Morgan introduced a superficially similar system using a sliding stub axle on a fixed pillar, used on Morgan Motor Company cars up to the current time. Although this has been widely described as "sliding pillar" it is in fact not one.