Buick HiPer Strut suspension. Click image to enlarge
By Jim Kerr; images courtesy GM Canada
The world of automotive technology doesn’t always have to include whiz-bang electronic programs or multi-passenger video displays. Sometimes, new technology appears to be so simple you may ask, why hasn’t someone done this before? Sometimes they have, but the materials weren’t developed yet that would let it survive a driver’s use or abuse. Other times, it is simply that none of the great minds in the industry have thought of it before. There is always room for new ideas, and Buick’s HiPer Strut suspension is one of them.
The HiPer strut suspension design combines a McPherson strut design with some of the benefits of a short arm/long arm design. To understand Buick’s HiPer Strut design, we should first take a look at the other designs. McPherson struts are an economical, lightweight design perfectly suited to economy cars. The strut is a structural part of the suspension, with a shock absorber inside, a coil spring (typically around the shock) and a steering knuckle connected at the bottom end. A lower control arm holds the bottom of the strut in place. A McPherson strut supports the vehicle, holds the tire upright and rotates to allow the tires to steer. Some vehicles use struts at all four corners of the vehicle. They all do the same job of supporting the body, although the rear struts are fixed so they don’t allow the rear wheels to steer.
The Short arm/Long arm design, sometimes called SLA or Double Wishbone design, has a higher cost, higher weight, but has better adjustability and better control of tire angles. This design uses A-shaped upper and lower control arms with ball joints at the outer ends that connect to the steering knuckle. A spring, either coil or torsional, is connected to one control arm to support the vehicle. The control arms hold the tire upright in the correct position, while the knuckle can be rotated on the ball joints to steer the vehicle. The tasks keeping the tire upright and steering are separated.