A simple suspension upgrade can transform your car’s handling, giving you more grip when cornering, accelerating and braking, as well as providing improved steering feedback, says Guy Baker.

Your car’s suspension couldn’t be more important – it’s what prevents you and your car from being shaken to pieces every time you drive down the road. However smooth that blacktop may appear to be, in reality it is covered in hundreds of tiny imperfections – each one just waiting to throw you around. Aside from your car’s tyres and seats, the suspension is all that separates you from the road, so delivering a comfortable ride is its primary purpose. But it also plays a fundamental part in your car’s handling – a water bed may be comfortable, but you wouldn’t want to corner on one, so delivering the optimum handling is also an essential role of your car’s suspension system.

And the most widely used suspension system – fitted to around 80 per cent of all modern cars sold in the UK  – is the MacPherson strut and spring set-up. Named after Earle S. MacPherson, who developed the design, it uses the axis of a telescopic damper as the upper steering pivot, with a bottom mounting-point on the hub or axle of the wheel. With just three key parts – a strut, a damper and a spring, it’s simple and offers low manufacturing costs, yet it is effective enough to be employed even on high-performance BMWs, Mercedes’ and Porsches. But car manufacturers have to make compromises in the design of their suspension systems: to deliver the optimum ride on a range of difference surfaces the car’s potential handling, grip and performance can be reduced. Which is why changing your car’s factory-fitted suspension for a sportier set-up can deliver greater grip when cornering, enhanced acceleration and braking, and could provide improved steering feedback too.

Springs

The easiest part of your car’s suspension system to change is the springs. Most aftermarket springs make your car sit lower, providing more responsive turn in, increased grip and reduced body-roll on cornering. Your wheels will also appear to fill the car’s arches better. Depending on what car you drive, a new set of springs could set you back anywhere between £100 and £400, but you will also need to budget a couple of hours of labour for fitting. It’s an affordable way to enhance the look and handling of your car, but bear in mind that without changing the dampers, the ride quality will become harder and your shock absorbers may wear out sooner. And if your car is already pretty low, then you may find you ground the sump on road humps.

Springs and dampers

A better option, if you can afford it, is to change both the springs and the dampers. That way you gain all the benefits of lower springs, but you maintain a better ride quality, because the dampers are matching to the coil springs. Your car’s dampers dissipate the kinetic energy from the springs by forcing oil or gas through a constriction valve. More expensive dampers even allow you to adjust the damping yourself, usually by changing the size of the valve opening. Non-adjustable dampers start at around £300 for four, while adjustables will set you back at least £400. To glean the maximum benefit and maintain optimum safety, make sure that you change your car’s dampers at least in pairs (either both fronts, or both rears) and preferably change all four at the same time.

As well as springs and dampers, there are other suspension components that also affect your car’s ride and handling

Gripping Stuff

• Bushes – used to separate individual suspension components. Original equipment items are usually rubber and perish with age. Polyurethane replacements last much longer and can improve your car’s ride. Bushes cost just a few pounds to buy, but are time-consuming to fit.
• Anti-roll bars – these reduce your car’s tendency to roll on cornering. Replacements can improve road-holding and traction without adversely affecting ride quality. Prices start at around £30.
• Drop-links – these link your car’s anti-roll bars to the suspension dampers or control arms.
• Strut braces – usually linked to the top of your car’s suspension, these reduce the degree to which your car’s chassis twists on cornering. Prices start at around £30.
• Geometry and alignment – after changing any suspension components you should have your car’s camber, caster and toe checked and adjusted to ensure everything is working safely and effectively. Typically this costs around £150.

Coilovers

On high-performance models the most effective option is to fit coilovers. These are bespoke suspension systems consisting of a shock absorber with a coil spring encircling it. The shock absorber and spring are assembled together as one matched unit, providing optimal damping. Unlike a simple shock absorber and spring setup, coilovers are totally independent and don’t require any additional small parts like bumpstops, ball joints and spring cushions. And the more expensive ones even allow adjustment of ride height and stiffness. However they aren’t a cheap option, with most kits costing upwards of £600. That said they do provide the best handling and ride combination and can last the lifetime of your car.

The best time to change your car’s suspension system is when the original one wears out, that way you minimise the expense. Have a good read on owner’s forums to decide which type and make of system is best for your car and your needs – it pays to learn from other people’s mistakes. And if you can get everything changed in one go, so much the better – that will reduce labour costs, which are often greater than the cost of new suspension components.

If you’re on a very tight budget, don’t ever be tempted to cut your existing coil springs to lower your car’s ride height. Safe operation is paramount in manufacturer suspension design and tampering in any way with original equipment systems could be extremely dangerous. It’s far better to save up for a proper set of lowering springs and preferably get them fitted by an expert.