Static Suspension
Strongs Of Center (Part 4)
Over the last century there has been a countless variety
of suspension setups, though many of them (which tended to have serious, even
dangerous, downsides), have fallen out of fashion. These days there are just a
few designs still in regular use, and while all of them have advantages and
disadvantages, they can all be very effective on the road and track. Here’s a
run down on the most popular designs...
Multi-link.
This
is the most modern and complex suspension design. In theory, this makes it the
best, but the complexity means it needs sophisticated 3D computer simulations
to accurately design, so it’s not as common on specially made race cars as you
might imagine. Multi-link setups have three or more arms per wheel, which means
every possible arc of movement can be individually designed without it
affecting another. For example, if they wish, the camber can change as the
wheel moves up and down without it affecting toe or castor like it tends to
with other suspension designs. In reality, getting suspension geometry perfect
is incredibly complex and manufacturers spend millions using sophisticated
computer programs to try and get it right. But once the car is modified beyond
its original intentions, these things are likely to be less than perfect once
again. Having said that, multi-link – provided you have fully adjustable arms –
gives a tuner an incredible range of geometry changes at their finger tips, and
while some racers may consider it overly complex, it does allow an almost
infinite range for you to tweak the geometry to your heart’s content.
Multi-link setups have three or more
arms per wheel, which means every possible arc of movement can be individually
designed without it affecting another
MacPherson
Strut.
This
is the most common front suspension setup, mostly because it’s simple and
cheap. While it’s not outstanding in any way, it’s effective enough that it’s
used on countless high-performance production and tuned cars. This setup
consists of a single lower arm, which the wheel hub bolts to, as well as a
smaller arm usually facing forward at an angle to prevent the single lower arm
moving backwards and forwards in the arch. The main disadvantage of this setup
is lack of adjustability and the fact that any upward or downward movement of
the wheel quite dramatically affects camber angle and even position in the
arch. This means the handling, theoretically, isn’t as good as a double
wishbone or multi-link setup, but the reality is, with the right settings, a
MacPherson setup is perfectly effective, even on some of the world’s fastest
track cars.
This is the most common front
suspension setup, mostly because it’s simple and cheap
Double
wishbone.
This
setup is generally considered to be the best for overall performance. It’s
fitted to a wide variety of sports and supercars, and is certainly the most
popular design for purpose-built race cars. Having said that, it’s fitted to an
amazing amount of normal cars too; with some big Honda and Peugeot saloons
having double wishbone suspension on the front from the factory. Double
wishbone suspension basically consists of two, parallel, V-shaped arms mounted
top and bottom, directly joined to the wheel hub, and the suspension shock and
spring is mounted through the Vs. The main advantage of double wishbone is the
movement of the arms gives a more linear and predictable change to the geometry
as the wheels move up and down in the arch. This means a good double wishbone
setup can give great cornering grip, and is especially useful on a tuned car
which has adjustable arms, as it’s much easier to work out what the effect of
your geometry changes will be compared to some other designs. A big
disadvantage of double wishbone, aside from the fact it takes up quite a bit of
room under the car, is while adjustment is predictable, having just two
suspension arms per wheel means adjustment of one geometry parameter tends to
affect at least one other. So, a lot of effort has to be put in to tweaking
each adjustment point to get everything as you wish.
This setup is generally considered to
be the best for overall performance
Torsion
beam.
Not
to be confused with the splined bars that replace springs on the rear of many
French hot hatches, torsion beam suspension is a relatively similar design
keeping the standard spring and shock combo, that has been used on the majority
of small to medium hatchbacks since the 1980s and is still popular today.
Torsion beam rear ends are as basic as suspension gets, being simply a
semi-trailing arm each side of the car, solidly connected to each other by the
horizontal torsion beam. This torsion beam allows some independent movement
between each wheel, but not complete freedom, in fact it acts a lot like an ARB
does to help resist body roll. The main reason this setup is so popular on
smaller cars is it’s very compact, giving more rear seat and boot space inside
the car, but in reality the majority of the best handling hot hatches from the
last three decades have had this style of rear suspension; so while it’s basic,
it does the job.
On the majority of small to medium
hatchbacks since the 1980s and is still popular today.
