Today we are completely and continuously bombarded by numbers—from near and far, in our work and even in our games. But if you deconstruct one particular human-machine interface, numbers mean nothing.
Supremely high levels of grip from tires on sports cars do no favors for your driving pleasure or the joyful mastery of a challenging, twisty road. In fact, they do quite the opposite. Super-high-grip tires mask mechanical communication. For the non-expert enthusiast driver without an Andretti level of skill, such rubber can often be unforgiving and unapproachable. Super grippy tires can make the ability to tickle the car’s natural limit of adhesion out of reach.
The real shame is that this is the exact point where enthused driving becomes a dance worthy of the effort. A sports car can be as rewarding a partner as Fred Astaire or Ginger Rogers, but fit horrendously grippy sneakers, and grace falls flat on its ass. Put simply, tires and suspension engineered for maximum possible grip deliver what they’re supposed to, but in inverse proportion to fun. And just to prove that this is not totally out of sync with today’s expectations, the poster boy for this notion just underwent a complete redesign that’s wholly devoted to improving human-machine communication and moderate grip: the 2016 Mazda MX-5 Miata.
Grip in the form of lateral acceleration and breakaway character is the prime offender in the modern crimes against driving fun, and it’s typically measured by the force of gravity in a lateral plane. In this metric, a car that can most quickly negotiate a 100-, 200- or 300-foot (30/60/90m) diameter skidpad in steady-state cornering in the least amount of time against others posts the highest grip. Here’s the formula: lateral g = (2.0 x pi)2 x (radius ÷ lap time).
Of course, grip on a skidpad proves only one thing: that tires stick well and the suspension keeps them mostly upright. That’s not where the joy or art of driving live, however. Better grip may mean negotiating a steady corner faster, but if you focus only on grip in the chassis engineering phase, the enjoyment of driving plummets. The breakaway character of the car’s and tires’ cornering ability at maximum adhesion becomes unforgiving and hard to read for many drivers.
Many disparate forces act on car manufacturers as they develop new model lines and model variants. Principal among them are tangible differentiators against competition. Winning the hearts and minds of sporty car fans often relies on a game of numbers brewed in a cauldron of 0-60 mph times, quarter-mile figures, maximum grip numbers, lap times, and nutso horsepower. Living by those stats adds up to one-upmanship that eventually leads down a rabbit hole of irrelevance. Mix all those ingredients together and you get an automotive Dolph Lundgren—great on paper but lacking any real charm in person. To put it another way, when is the last time you drove a spec table? I’ve tested well over 1,000 cars, and I can honestly answer this question with “never.”
The Miata proves there’s a better recipe. Mix in the touchy-feely feedback of communicative steering, light weight, equal fore-aft weight balance, and a low polar moment of inertia. Cook up a suspension absorbent enough to keep tires planted and talking to the driver as continuously as possible. Toss in seats that tell the pilot what’s happening at the chassis level. Stir. You’ll have the most pleasing automotive meal you’ve ever eaten rather than the numbers-driven bowl of twigs and bark served up by the max-power, max-grip, brick suspension car kitchen. And here’s the art part: you can’t simply wave a magic wand and have all these elements come to life in metal and rubber. It takes heady fortitude and philosophical strength of principles (human-machine communication) to find the sweet spot. This is where things usually fall down, but the new Miata is one car that stands tall in this equilibrium. (And for those keeping track, Mazda has done this for more than two decades.)
It’s worth noting there are a few other holdouts besides the Miata today. Mini Coopers offer driving fun without much homework. Ford’s brilliant Fiesta ST and Focus ST and the Subaru/Scion BRZ/FR-S twins are all happy road puppies. And the brilliant new Ford Mustang redefines what a brawny muscle car can feel like. But inspired by classic British sports cars, the Miata’s sole purpose since 1990 has been satisfying feedback, lightweight agility, and most of all, driving fun. This year’s edition has deconstructed sports car philosophy to these most bare and best necessities, delivering what you want as well or better than every previous iteration. It qualifies as a minor miracle in today’s car-building climate, where the push for autonomous driving capabilities rages at the periphery.
The origin of grip lust
To understand today’s excessive fascination with grip, it helps to recall a time when the drivers were fat and the tires were skinny. Go back 60 years or so and British roadsters with modest power and meager tire grip awoke a sleeping American sports car market. Ultimate cornering grip was quite low, and this was as much a function of vehicle weight (where lighter meant grippier) as it was keeping tire treads in the same plane as the road surface (which was difficult due to downright aggro suspension technology and geometry).
As the automotive world returned from war materiel to car production in the late 1940s, most cars on the American road used rudimentary chassis bits: drum brakes all around, live rear axles on leaf springs (which did double duty as both springing and locating devices), high-sidewall tires with highly flexible bias-ply construction, and suspension generally focused on delivering whipped cream ride quality. Steering and handling were things you simply endured. On a good day, the average car of the late 1940s could generate perhaps 0.4 or 0.5 gs of cornering force. Sports cars of the era weighed about half that of an American sedan and required proactive, repeated maintenance. Still, these old sports cars offered completely approachable dynamics and more driving fun and adventure than your own private pony, much like the modern Miata. (Today, sedans can achieve twice that amount of grip, return twice the fuel economy, release negligible emissions, and avoid ejecting you in a crash.)
But time is nature’s engineer. Technical developments and growth in grip and performance in general has become the game rather than a jaunty, kerchief-flowing ride through the countryside. Performance figures improved, grip escalated, and bench racing—car nerds arguing over rival models’ speed—ascended. Nowadays we’ve somehow gone wrong and fallen in love with loveless numbers. We’ve strayed from what binds us—enjoying and perhaps conquering challenging roads—to worshipping at the altar of numbers that provide little automotive enlightenment.
Car talk: The language behind the metal
Despite the obsession with numbers, cars remain devices of analog communication. For the purpose of perceiving and communicating cornering force to the driver, any vehicle continues to deliver information today in several ways, and Miatas have always excelled in these areas:
- Body roll: A primary, fundamental way to inform the driver about cornering and therefore a progressive indicator of grip. However, on low-friction surfaces (water or wet leaves, sand, pebbles, etc.), tires lose grip with far less body roll than the driver might anticipate if conditions were dry.
- Yaw: The car’s rotation or rate of change in rotation relative to the change in actual direction. An oversteering car generates yaw, but at any one moment during that slide, not necessarily a change in direction.
- Steering effort and weight: As cornering forces build, steering should gain weight and require more effort. As the limits of adhesion approach and begin to fall off, steering should lighten, giving the first and primary indication to the driver that grip is diminishing and a change in driving approach should be considered.
- Tire noise: A singing tire is a happy tire. A screeching tire is not. Make your tires sing.
- The seat (and therefore, your butt): Great drivers develop very sensitive gluteus maximi. Great-driving cars speak to those glutei before stuff gets ugly.
- Vision: This actually comes last in this list. When driving aggressively, vision must feed your planning for the immediate future, not your present tense. Once a skid begins, you obviously see it, but by that time, it’s likely too late to prevent it.
These characters are what create the pleasure, directness, and responsiveness that a proper sports car provides its driver. The joy comes in the mother tongue of feel, tactility, and pure communication. A car speaks to you through steering feedback and in the way it moves about on the road—the anti-numbers.
While genuine numbers absolutely play the central role in real racing, how many enthusiasts who participate in open track days actually compete via lap times? It’s a minority. If you’ve ever done a lap with a pro, you certainly remember speed, but memory is relative. You keep coming back when you master it, not when you crash because of it.
In fact, an obsession with numbers and grip has occasionally resulted in a serious affront to the joy and pleasure of driving. The religion of grip gave us the 1984 Z51 Corvette, a car that could achieve a remarkable, world-beating 0.90 g cornering force on a skidpad. This figure was widely accepted as a first by a street car. But actually living with that Corvette on anything but glass-smooth tarmac was a teeth-gnashing, kidney-punching, experience similar to nine rounds with Roberto Duran. Chevrolet quickly rethought the car’s suspension tuning.