What is multilink suspension?
- A superior independent suspension system
- Uses several short links to attach hub carrier to body
- Provides consistent handling and traction
Independent Rear Suspension, usually abbreviated by manufacturers as IRS, has been used in road cars for many years. An independent system allows each wheel on the rear of the car to follow irregularities or bumps on the road surface without affecting the wheel on the opposite side of the car.
There are a few IRS designs that have become favoured by manufacturers over the last few decades. Swing axle, trailing arm and MacPherson strut systems (more here) have all been used by mainstream manufacturers but all of these have disadvantages in comparison to modern multilink suspension.
The main disadvantage that these systems share is poor camber control. As the suspension is compressed (due to road surface, body roll or acceleration) the wheel moves upwards in relation to the car body, as this happens the 'camber' angle (or tilt) of the wheel changes. This leads to inconsistent handling and traction, especially during periods of body roll and heavy acceleration.
The abovementioned systems are also heavy in comparison to multilink systems. In very general terms, lighter suspension components improve suspension control and in turn, ride quality.
For these reasons the multilink suspension type has become more popular with car manufacturers since the 1990s.
Multilink is considered to be the best and most functional independent suspension system that can be used on a production car. A multilink design uses several short links (or arms) to attach the hub carrier to the car's body (or a subframe). The links are configured to ensure that the camber angle of the wheel remains unchanged during suspension movement. 'Toe' and 'caster' dimensions are also controlled by the links depending on their initial design geometry.
Multilink suspensions can use as few as three links, however, there are many different interpretations of the theory and some designs use as many as five.
Does multilink suspension have any disadvantages? In short, yes... Such systems are more complex and incorporate more components, making them more expensive to design and produce. For this reason the systems were first introduced by luxury brands. That said, lower vehicle production costs and higher customer expectation have more recently seen the technology filter down to many large and midsized mainstream vehicles.
Development of the multilink suspension systems is ongoing. For example, Italian company Magneti Marelli (most famous for its auto electronics) is making significant headway in producing cost-effective multilink systems for small cars. Its new designs incorporate flexible links, the benefits of which are said to allow fewer total parts, simplified bushing designs and reduced noise transmission into the passenger compartment.
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-- with staff
Article updated October 2009