Suspension adds the cream to the cosmetics

By T. Uncle

"Compromise" is probably the most significant word in the lexicon of car suspension designers.

Compromise is what designers have to do to strike a balance between acceptable standards of ride comfort and road holding.

In the absence of any ideal solution, carmakers are forced to make a decision about what type of buyer they are appealing to when the first preliminary sketches of a new model are made.

If they are seeking a younger market, then the accent will most likely be on a suspension that delivers crisp, responsive handling. The tradeoff is that crisp handling usually requires a tighter, less bump-absorbing suspension setup.

If, on the other hand, the car is intended for a more mature market where comfort is the prime criteria, a soft, cushy set of springs and relaxed shock absorber rates will do the job nicely -- provided the owner doesn't one day suffer from a rush of adrenaline and decide to start throwing it at corners.

The trick is deciding exactly where that tradeoff should take place.

The more development money spent on the suspension, the less noticeable the tradeoff: A Mercedes-Benz or BMW, even at the higher end of the scale, will generally offer relatively high degrees of both road holding and ride comfort. The tradeoff is there, but it's more subtle than at the lower end of the market where less complex, cheaper-to-produce suspensions systems are the norm.

The problem is that some carmakers manage to build vehicles that exude sportiness in the way they look, and even the way they go, but fall down badly in the suspension department when taken slightly beyond normal limits. Those highly effective brakes, and that efficient multivalve V6 are of little use if the corner that has been approached with such enthusiasm manages to overcome the abilities of the suspension.

Given the fact that some drivers are dissatisfied with the basic characteristics of their car's suspension, there are things that can be done to shift the emphasis more towards the sporting end of the scale.

Some carmakers offer modified suspensions as an after-market fixture on certain models that happen to have the right sort of looks, but the wrong sort of dynamics, for buyers with "sporting" aspirations.

Sometimes, these aspirations might be confined simply to the way the car looks, in which case it is a simple matter of lowering the suspension, fitting bigger alloy wheels and tires, and hang the negative effect this might have on comfort, or even handling.

A poorly considered, "cosmetic" suspension job is never likely to do much more than provide the car with an aggressive look.

Ill-conceived spring and shock absorber rates, crudely shortened springs and maybe a touch of negative front camber for extra visual effect invariably result in a car that bucks and lurches on its short-travel springs, and is subject to wild torque-steer -- which is what happens when wildly offset wheels tug at the steering when they encounter bumps on the road.

A lower, firmer-riding suspension can, on the other hand, deliver the sort of handling response that will delight an enthusiastic driver. A properly developed sporting suspension will use springs that are rerated to cope with the shorter travel available, and are mated with new, compatibly rated shock absorbers. As well as lowering the center of gravity, which inherently will have a positive effect on the car's handling balance, the car will lean less in a corner and even be more stable at higher speeds.

However, there are other factors to consider: lowering the suspension will also change the front suspension geometry, front wheel camber and castor angle change as the vehicle is dropped closer to the ground, so the basic characteristics of the vehicle can be altered in unpredictable ways, depending on the expertise of whoever is doing the modifications. The same applies to vehicles with independent rear suspensions.

The bottom line is that modified suspensions can be a good thing up to a point: taken just that little bit too far, or simply modified without thought to the likely consequences on handling and road holding (they are two separate things) the car owner can end up with an expensive-to-fix mess.

The bottom line: any suspension modifications should be left to proven experts. Ideally, they should be sanctioned by the carmaker either through the dealer, or as part of an approved options list. Many carmakers who are tuned in to their markets offer these services in a flourishing industry that recognizes the basic need of most motorists -- to be different from the rest.