Sitting Pretty: What’s the Perfect Driving Position?
You’d think that how we sit in cars wouldn’t be a thing to debate about. You get in, move the seat and steering wheel around, and off you go. But what’s the right way to find your perfect driving position?
Few people have sat in as many cars and needed to sit in them correctly as our expert among experts, our resident pro race car driver, Randy Pobst. So I’ll start by asking him:
“Before track driving, I adjust everything to what feels a bit too close. The padding compresses and offers good leverage for control, so being a little close works best for me because by the time I get out there, it’s not too close anymore. I lean back a bit, often meaning there’s a gap at my lower back that I fill with a rolled-up towel, and I have some bend at the elbows, because turning the wheel requires extending your arms. I’m relatively close to quickly countersteer if necessary, which is also a bit close for my legs—so I splay them a little. But on the track, I don’t notice.”
To Sit Low or High, That Is the Question
Nevertheless, when I get into a test car after another editor’s driven it, I often experience a moment of zero-g free fall before finally landing with a thump on the bottom cushion. The seat’s been left pancaked to the floor, and to see out over the cowl, I have to sit up with the perfect posture of Eliza Doolittle. Are some of my co-workers sleeping in here? When confronted they’ll describe—with stone seriousness—that they want to lower the center of gravity. And, yes, a lower CG does reduce weight transfer, and that maximizes grip (because tire grip is nonlinear with vertical loading). I wonder what their living rooms look like: I’m imaging tatami mats and chairs with their legs sawn off.
I sit exactly the opposite of these lowlifes, raising the seat bottom so high and aiming the seat back so vertically that my skeleton nearly becomes a temporary structural member of the car. My defense? To get the best outward vision I can.
Both driving positions—highchair and supine—have had their champions (so to speak) among racing drivers. Back in the 1950s, Juan Manuel Fangio, my Numero Uno of the best who ever lived, sat like me, bolt upright, elbows angled out, trying to be as high as his stature allowed. Ten years later, Colin Chapman lowered Jimmy Clark in his Lotus 25 Formula 1 car and stretched his arms nearly straight to trim frontal area and aerodynamic drag—and yes, lower the center of gravity.
Let’s Ask the Mercedes Automatic Seat Setting
Sometimes conundrums like this need a third-party arbiter, and Mercedes-Benz may have stumbled into that role via something it calls Automatic Seat Setting, which claims to automatically put you in the proper position. I came across ASS (my acronym, thank you very much) while recently driving a Mercedes-AMG GLE 63. On its info screen is a slider you can move anywhere between 4-foot-9 and 7-foot-3. I slid it to 6-foot-1 (me) and tapped Start Positioning, and suddenly, everything started to whir and disengage me from my beloved Fangio Driving Position (FDP) as the car commenced to render its judgement.
When it stopped, I was about three quarters of an inch closer to the wheel, a tad lowered, and to my delight, only slightly more reclined. The rearranging process feels odd, as it doesn’t follow the sequence of adjustments humans would make, but the final result was a whole lot closer to FDP than the sleeper-car recline of my co-workers.
Why does it decide to stop at these positions? Although the first thing you learn about ergonomics is there’s no such thing as an average human, I’ve ditched that to use an adjustable mannequin composed of the head, limb, and torso lengths of the average American male (5-foot-9.6, plus shoes and hair) and female (5-foot-4.2) to measure comparative headrooms and rear knee room. With the mannequin adjusted to “average guy” and positioned in the GLE, I asked the seat to go to its 5-foot-9 position. It wound up matching the mannequin surprisingly well.
So is Mercedes’ positioning system using male or female proportions? As it only asks for your height, maybe it’s their average? I asked Mercedes for some illumination and got this back:
“The aim for this is to return drivers, who use extremely poor seating positions, to the more optimized standard. The seating positioning is based on both 3-D digital human model simulations and measurements of real driving postures, and we have developed ergonomics algorithms that pre-adjust everything on the seat and steering wheel for our customers as suitably as possible.”
I’d like to thank our arbiter, Mercedes-Benz, for a verdict that’s 95 percent in my favor, though I’m guessing that the real point is to coax drivers into a better position for airbag deployment.
Now, Let’s Ask the Staff
Just to give an idea how fractured our staff is over this very basic issue, I asked them how they sit in cars. Ever linger in your driveway until late at night wondering if you sit in your car just like Jonny Lieberman does? Here you go:
Jonny Lieberman, senior features editor: seat low, upright seat back, steering wheel close
“I went to too many driving schools to even entertain sitting any other way.”
Nick Yekikian, associate online editor: seat low, upright seat back, steering wheel close
“I like the feeling of sitting in a car, not on a car, so I always slam the seat right down.”
Scott Evans, features editor: seat low, reclined seat back, steering wheel close
“Jonny can’t grasp the idea of someone having short legs and a long torso, but my Sicilian heritage is likely the reason that the ‘classic Italian driving position’ doesn’t bother me.”
Greg Fink, digital editor: seat high, upright seat back, steering wheel far away
“I’m the opposite of Scott: Torso of a small child and long dancer legs. I usually put the chair up as high as I can go while still clearing room for my hair. I guess it messes with CG, but I find it easier to place the car when I can see more of what’s ahead of me.”
Erik Johnson, group editorial director: seat high, upright seat back, steering wheel far away
“I often sit closer than I otherwise would in manual cars because I, too, am more torso than legs. I don’t care about CG, as we’re driving on roads, not looking for thousands of a second.”
Alisa Priddle, Detroit editor: seat high, upright seat back, steering wheel close
“As a short-legged person, I often adjust the seat up to its highest setting for an optimal vantage point.”
Ed Loh, SVP of content: medium seat height, upright seat back, steering wheel close
“I like to think I sit like a WRC rally racer—in an upright position with the steering wheel close-ish so I can shuffle-steer, but the WRC guys basically have their seats mounted to the floor, and I don’t like to sit that low.”
Christian Seabaugh, features editor: medium seat height, upright seat back, steering far away
“My seat’s high enough for visibility but also as low as possible to the floor (easy because I’m tall). The seat is pretty far back so my knees are slightly bent and I can push hard against the dead pedal.” (FYI, the dead pedal doesn’t do anything, Christian.)
Frank Markus, technical director: seat low, upright seat back, steering wheel far away
“My seat bottom is as low as possible for optimum CG, forward enough to press hard on the floor beneath the pedals in case the brakes fade that much, and the seat back is very upright, affording a slight bend in my elbows.”
Mark Rechtin, editor-in-chief: seat low, upright seat back, steering wheel far away
“I guess it goes back to learning how to pilot a vehicle via motorcycle rather than car. I always like to feel like I’m sitting in the car rather than on the car.”
Chris Walton, road test editor: seat low, upright seat back, steering wheel close
“I sit low and close to the steering wheel.” And then he starts getting all metaphysical: “I sit low to feel like a part of the car, to be aware of the car itself.”
As they say, allow me to unpack this. Rather than lowering his body to descend the center of gravity, his goal is to tune more directly into the car’s g-forces, which can be sensed more clearly without the exaggeration of body roll. “It offers me the chance to ‘listen to’ (feel) as much as I ‘say’ to the car (drive),” Walton said. Hear the car’s whispering without any distortions.
What Your Body Is Telling You About Your Driving Position
As with walking, driving requires both sight and balance. As a nerd who burns his fingers soldering the wires of clumsy accelerometers and yaw rate sensors, I find the inner ear a shocking thing to behold. Each ear packs a trio of orthogonal yaw rate sensors (the anterior, posterior, and horizontal canals) and two accelerometers: the saccule (that senses vertical motion, like when standing up) and another (of greater interest here) that senses horizontal acceleration, called the utricle. Five motion sensors per ear, 10 in total. And they’re very tiny.
Inside the utricles, the structures that do the measuring are 2mm by 3mm. Imagine: When Lewis Hamilton shrieks through the high-speed Copse right-hander at Silverstone in his Mercedes-AMG F1 W11 EQ Performance Formula 1 car, it’s these two tiny dots—pebble sized—that are signaling 5 g’s of lateral acceleration to his brain. Astounding, isn’t it? This is multiple times what they were evolved to measure. Curiously, the saccule and utricle are thought to retain a trace of their ancient role in hearing, which makes it curious that Walton uses the word “listening” to the car. These specks don’t work alone, though. The brain weighs and cross-checks them with the canal rotation sensors, your eyes’ view of the scene ahead (which is processed more slowly), and even such inobvious corrections as neck angle, and then works it all out.
The relative contribution from our eyes and inner ears is the battle ground of our debate about seating position. Sit high for a bigger view and better three-dimensional perception? Or lower, to sense g-forces more accurately? Being that our eyes and ears are at the same height (they’re a package deal, right?—either they’re all up or all down), they can’t be split up and repositioned. Perhaps if our bodies were designed by racing car engineers, our inner ear sensors would have wound up around our navels (which is approximately our center of gravity).
As a for-instance, let’s compare the center of gravity improvement from sitting lower versus its cost in compromised outward vision. To sample this, I placed that same 5-foot-9 male mannequin in our long-term Mazda 3, which I happen to be driving. After positioning him, the driver’s seat could be vertically adjusted by 2.5 inches.
Our Mazda 3—a front-drive, six-speed manual version—weighs 3,027 pounds. The weight of our average guy is 180 pounds, or 5.6 percent of the car-plus-driver total. So in this case, dropping the seat from its highest position to its lowest lowers the Mazda 3’s CG by 0.14 inch—a little more than one-eighth of an inch. Separate your thumb and forefinger by the thickness of two SD cards (actually, less than that). This is irrelevant for a road car; your effort’s much better spent adjusting your tire pressures. For a racing car, though, nothing’s irrelevant. In 1986, Gordon Murray took supine-ness to a new low with his Brabham BT55 Formula 1 car, which, for mainly aerodynamic reasons, laid its drivers as close as they’ve even been to a luge driver blurring down the St. Moritz ice. The drivers complained of sore necks.
Now how about the flip side—the loss of outward vision from lowering the Mazda 3’s seat by that 2.5 inches? Doing so pushes away the closest thing you can see on the ground by 5.2 feet (from 11.9 to 17.1 feet). Said another way, it lengthens your forward blind spot by 44 percent. For a road car, lowering your seat might be justifiable for nebulous “sensing the car” reasons, but not for lowering CG.
One More Time, From Our Race Car Driver
Earlier, I forgot to ask Randy how high he sits.
“I prefer to be low on a racetrack,” he said. “However, on street courses and autocrossing, I sit a bit higher for vision.”
As always, consistency is the hobgoblin of small minds. I’m constantly amazed by high-performance road cars with one-piece seats that can’t be raised or their back angle tilted in a ridiculous tribute to what they use in race cars on high-speed road courses. (Last year I had to stuff a rolled-up towel behind my back to see better out of the McLaren Senna.)
Mr. Pobst repositions his for the task at hand—so whether he’s on a race track or on his way home afterward, he’s always sitting pretty.
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