Turn the steering wheel at 40 mph and the little Civic turns; add steering lock, and it turns more. Neck-snapping cornering power is what handling is all about, and the Progress Grove Honda Civic leaves your neck muscles screaming for relief. Exceeding 1.0 G cornering force is not that unusual-for race cars. But for a daily-driven '89 Civic with aftermarket springs, antiroll bars, shocks and bushings, and no fender flares for fatter tires-well, that's really an accomplishment.
Let's gain a little perspective. A Formula 1 car corners in high-speed turns at 3.5 Gs, an Indy Car at 2.5 Gs, and a British Touring Car at about 1.5 Gs. The F1 and Indy cars have enough downforce at 190 mph to triple the load on the tires. That accounts for most of the traction. They all have state-of-the-art chassis structures, sophisticated suspension systems, and none of them would last 30 seconds on the streets we drive every day. So, any car that can be comfortably driven on the streets and highways of your neighborhood and exceed 1.0 G cornering force is quite a machine.
Thirty years ago, the SCCA Trans-Am Camaro campaigned by Roger Penske and driven by the legendary Mark Donahue could barely reach 0.90 Gs on the skidpad. Even in 1999, stock cars like the Corvette, BMW M3, or the Toyota Supra Turbo are not able to pull 1.0G lateral acceleration on the skidpad.
So what does it take to turn a mild-mannered Civic into a mean and nasty corner-basher? It's simple: traction! Actually, it's not that simple. Traction is the key, but many elements come into play when attempting to get maximum traction. The obvious place to start is with tires. Progress used the Toyo Proxes RA-1 (205/50ZR15) and the Toyo Proxes T1 Plus (205/40ZR17) for this project. When it comes to tires, traction is increased when the tire rubber compound is softer and when the tire contact patch is bigger. The tread design and sidewall construction also play a role in allowing the tire contact patch to work on the road surface and maintain contact with the surface. Even the softest tire will not achieve good results if the tread design and sidewall construction miss the mark.
Both of the Toyo Proxes models used in this test worked extremely well. The RA-1 is a DOT street-legal racing compound tire. This tire provides serious traction for competition purposes. By using a softer rubber compound, tire makers increase traction but at the cost of accelerated wear. The Toyo RA-1 offers excellent grip, but wear is still outstanding for this type of tire. The T1 Plus is a street compound high-performance tire that offers outstanding cornering performance, a tread pattern suitable for most weather conditions and great wear characteristics.
The skidpad left and right turn average on the T1 Plus was an incredible 0.964 Gs. For a daily-driver offering outstanding wear and wet road performance, this cornering force is awesome. On the RA-1 tires with the more aggressive tread and sidewall design and stickier rubber, the left/right average on the skidpad was a whopping 1.007 Gs. To get this number, many racers would sell important body parts.
Before you bound off the couch and dash out the door for your nearest Toyo dealer, there's more to this story. While tires make the traction, the suspension is what dictates how the tires work. To get those kinds of skidpad numbers, the tire contact patches must be equally loaded and flat on the road surface during cornering, braking, and acceleration. If the tires are not correctly loaded, the balance of the car is off, speed is lost, and drivability takes a big dump. And if the tire contact patch is tilted, you might as well save a few bucks and buy a set of 155/70R13 tires, because that's about how much traction you'll have on tap if the suspension does not keep the meat of the tire on the ground.