Suspension Truth #1: Planes, Trains and Automobiles – The Psychology of Suspension Tuning

What’s your least memorable train ride? Simple question, right? If you’re reading this, I’m going to assume all of them. Unless a screenwriter threw you into an adventure film without your consent, it’s what we’d expect. This brings to mind a popular driving metaphor – ‘handles like it’s on rails.’ That’s our ideal in suspension tuning, to be glued to the ground and also as comfortable as possible. Easy when you’ve controlled every degree of freedom as with a train track and groomed earth beneath.

But what about your least memorable plane flight? Again, I’d hope most of them. How about the most memorable one – turbulence anyone? Whether chop, CAT, or simply bumpy air, turbulence can be annoying, as in delayed beverage service, or utterly terrifying. The unpredictable, jerky movements of an airplane caught in Mother Nature’s fury sharply draws your attention to the immediate environment. You aren’t relaxed anymore, thinking about the miles of air between you and the ground. You have to trust in your pilot, crew and the plane itself to handle the situation, working in harmony to return you safely back to Earth.

In between these extremes is the spectrum of what an automobile suspension can offer. As a driving enthusiast and amateur racer in my 20s, I only wanted suspensions that made my car handle better and go faster. Comfort was secondary and in fact I believed (as many do) that to be fast you must be uncomfortable. Ah, brainwashing by race companies and the follies of youth! Having trusted marketing hype from both automakers and aftermarket companies, I’ve come to see patterns in the past 15 years of my pursuit of Suspension Perfection. Ultimate speed and ultimate comfort. How are they linked, if at all? Can I make my trip to the race car unmemorably smooth and also have razor-sharp handling for a backroad jaunt, autocross run, track session or hill climb? What about safety, responsiveness and predictability?

Any automaker has to fulfill the task of keeping a vehicle on the road. They can do it in a bare-bones fashion, like a budget economy car that doesn’t inspire much confidence but gets you from point A to B. At the very high end, we have the Holy Grail: a buttery-smooth ride with incredible handling. Normally you pay superlative prices (Aston Martin, Ferrari, etc) for this achievement, but I’ve found that cost has very little to do with making an exceptional suspension. You need to understand the designer’s mandate, see if that matches your needs, then choose components (or a vehicle itself) that deliver. But we don’t get handled a personality test results for a Honda Civic, Toyota Camry or Porsche 911 Carrera. We have some bias based on past experience, what we’ve read, felt or been led to believe. But what really goes on in that murky black magic area of suspension design? By starting with an examination of the psychology behind a vehicle, why it exists, we can understand certain design choices then make targeted improvements to a production-based road car to the point it feels truly amazing.

Please note, this kind of suspension harmony matters whether one get groceries or chases championships. It’s been a fascinating process of discovering the truth of how grip produces both great ride and handling both. For a street-driven passenger car, how the suspension deals with the road, mile after mile, creates a somatic experience that can promote either ease or dis-ease. I’d rather see a driver smiling and relaxed after a trip than stressed and hurting. A relaxed (not numb), in-control driver is a safer driver and a happier human being. There’s also a very important somatic experience to the race car driver, who needs to have hyper-confidence in their machine’s responsiveness to dance it on the edge of adhesion.

One video in particular was very illuminating to me. It was of a journalist who had a chance to drive a few laps in a Formula 1 car. Once the lengthy process of preparing him for the experience was complete (simplified as it was in his not-very-physically-fit case), he took his laps, whooping the whole way through. Once he stopped the other reporters asked a seemingly rhetorical question ‘you just drove a Formula car! Wasn’t it really harsh?’ to which our lucky journalist gives a surprising answer: “No, in fact it was quite smooth once you were up to speed!”

Is it that really all that surprising to hear this truth? To give a driver confidence and ultimate speed, the proper suspension has to keep the tires in contact with the road. What’s good for the rather-soft tires (imagine driving around on a partially cooked egg) is good for the very soft driver. Going stiffer than is necessary robs grip and induces more discomfort. The just-stiff-enough setup will reward the aggressive, competitive or racing driver in many ways.

We’ll continue our explorations next time with a topic that is even more subtle – what does it mean to have a “Sport Suspension” and do you really want one?

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