Engineering is the art of compromise. When deciding on suspension settings (i.e. spring height/stiffness, shock absorber characteristics, and sway bar diameters), engineers spend countless dollars and man-hours to come up with a balance between a car that feels refined and one that attacks corners with enthusiasm.
Yet some have come to equate a low stance with improved performance, one of the misconceptions that made the automotive aftermarket a 26 billion dollar industry last year.
We've found that - as with many things in engineering - it's a case of diminishing returns. We urge you to think twice before buying into the promise that an aftermarket spring kit or suspension system will improve much more than the car's appearance.
While there are cases in which the car will corner faster on smooth roads, there are too many side effects to mixing and matching off-the-shelf components for us to list here. Properly engineered aftermarket suspension systems cost $1,000 or more, and even then are more suited to the smooth surfaces of a racetrack or German Autobahn.
In real world use, the ostensibly sportier car is often slower from point to point. Unless the roads you drive are mirror smooth, spend plenty of time benind the wheel of a car with the same components before comitting yourself to a suspension system that will make your car ride and handle unpredictably.
And if you're serious about improving your car's performance, spend the money on improving yourself as a driver: as the old saying goes, "The most important nut is the one behind the wheel."
Exhibit A
“You’ve seen those ground hugging Golfs and bulging-wheeled BMWs, all Max Powered and looking as though nothing normal would stand a chance against them when a road turns tight and twisty. Why, then, do they never seem to be going quickly when you see them?
Because such cars, with their minimal-profile tyres and lowered, rock-solid suspension, tend to be thoroughly horrible to drive. Their structures have to absorb shocks for which they were never designed, the road roar is usually huge, imperfections in suspension geometry are magnified, and any subtlety of steering feel goes right out the window.
On a smooth, dry track, a stiff, low road-roller would probably prove faster than its out-of-the showroom alter ego. But on a real road with real bumps and real contours, you’ll be bucking and bump-steering and bottoming-out and having a miserable time, while the standard example fills and slices the dips and bumps, keeps the suspension loadings where they should be, gives you all the right messages free of an overlay of extraneous noise. Ride and handling is a compromise, and the mark of a good suspension system is that it does both well. You can skew the compromise to suit your tastes, of course, but only within limits. Manufacturers do it all the time, which is why a [third-generation VW Golf] GTI will grip harder, corner flatter, feel firmer and rattle your teeth more than a GL. But the compromises are painstakingly worked out, particularly the matching of springs to dampers to seat-cushion hysteresis, and you meddle at your peril...”
-- "Wide ’n ’low: on the road to rack and ruin" -- CAR, Dec. 1997
Exhibit B
The "L-Tuned" version of the Lexus IS300 has springs that are 1 inch lower than standard as well as larger anti-roll bars. Yet when Motor Trend tested it in their September 2002 issue, they found "a stock IS300 posted slightly better speeds through the slalom cones." [Motor Trend, September 2002]
Exhibit C
Recognizing the popularity (and profit) of aftermarket lowering springs, Volkswagen offers Eibach aftermarket springs as accessories though its own dealerships. European Car tested an Audi A4 3.0 Multitronic with Eibach springs in their April 2003 issue, at which time one of their staff observed:
""I can remember driving only one car that paired Eibach's Pro-Kit springs with stock dampers and not hating it. This is not that car. The springs fitted to the car have transformed it from a wallowing, soft and underdamped car riding on marshmallows to a badly underdamped car riding on its long-travel bumpstops, a.k.a "supplemental springs." What I didn't expect was for the damping to decay in 40 minutes of driving the car on public roads. I would need to perform more-official tests before declaring the dampers had faded, but they certainly seemed worse at the end than at the beginning.""
Exhibit D
In the words of Gary Peck, vice president of sales and marketing for Eibach springs, "Performance springs are designed to help the car realize its best handling capabilities. Lowering springs are made to offer a more drastic reduction in ride height regardless of what they do to the car's suspension performance."
Are you sure the person profiting from your purchase knows enough about your particular model to tell the difference?
Exhibit EWe once managed a firm specializing in aftermarket upgrades for European automobiles.
When people came in insisting they wanted to lower their cars, we would generally try to talk them out of it. (After all, the owner himself regretted altering the suspension of his 95 BMW M3, but kept the car modified "for business purposes.")
Few listened, and most later admitted regretting the change.
During the last month, we ran into a three of our former customers, all of which bashfully admitted they liked their car better now that they had reversed the changes and returned the cars to stock. (The Nissan owner is a former co-worker who bought the legendary 91 SE-R with an aftermarket suspension already installed).
Car: 1999 BMW M3
Suspension 'upgrades': DINAN Stage 2 suspension->Bilstein Gruppe N suspension
Owner feedback: "I had forgotten how good a stock M3 suspension actually is."Car: 2000 Audi S4
Suspension 'upgrades': H&R coilover kit
Owner feedback: "Now that I've returned the suspension to stock, I've decided not to sell it."Car: 2002 BMW M5
Suspension 'upgrades': Hammann suspension kit
Owner feedback: "The aftermarket suspension looked great, but took away more than it gave. The car is much nicer to drive with the factory set-up."Car: 1991 Nissan Sentra SE-R
Suspension 'upgrades': H&R Springs, Tokico struts, Suspension Techniques sway bars
Owner feedback: "I can't drive it on the streets because it's too stiff for me."Keep in mind that the Audi and BMW owners did not shop by price or 'mix and match' springs and shocks from different manufacturers.
They bought what are considered to be the best engineered, most 'streetable' setups available for their cars and were still dissatisfied in the long run.Need we say more?