Brakes, Steering and Tires: Major Advances in Safety, Handling and Affordability
Brochures for new cars and trucks are filled with wonders such as CD changers, satellite navigation and seats that remember how close to the pedals you prefer to park your posterior.
But if you can’t keep the vehicle under control, those things become moot. A hot tune on the stereo is cold comfort when you’re staring through a shattered windshield at the wrinkled rear of the car you just plowed into.
Until recently, the auto industry believed that safety didn’t sell. Creature comforts and cheap prices did.
Now the equation has changed.
Breakthroughs in computer and electronic technologies give auto makers the ability to pack vehicles with systems that improve safety and handling and are affordable as well.
“The Holy Grail of automotive product development is to find ways to both improve the product and reduce the cost so people will buy. And in a lot of ways, that’s what new technology is allowing the industry to do,” said consultant George Peterson of AutoPacific Inc. in Santa Ana.
The industry is doing this especially well with systems that help keep the vehicle and the road in contact: braking and steering systems and tires.
The first big breakthrough was the anti-lock brake system, or ABS, and it is being improved yearly.
After being offered first as an option on luxury cars, ABS is now available as standard or optional equipment on many cars and trucks.
“It is in the top five of things people say they want on their next vehicle,” Peterson said.
And today new technologies are allowing the industry to move past ABS into more sophisticated traction and skid-control systems.
“It’s the logical process, now that ABS is pretty well available,” said Robert M. Rivard, engineering director for Robert Bosch Corp.’s brake and traction controls division in Detroit.
ABS takes over in a panic-stop situation, applying and releasing the brakes up to 15 times a second to keep them from locking the wheels and putting the vehicle into a straight-line skid.
A traction system uses the “plumbing” already in place for ABS and adds electronics that control both engine speed and braking pressure on individual wheels.
A traction system “can apply the brakes when it senses a wheel has started to spin,” Rivard said, “and if both sets of wheels are spinning, it can communicate with the engine control module to tell it to reduce the engine torque.”
Next up--yaw, or spin-out control--a system now available as an option on the Lexus LS400 sedan. It adds to ABS and traction control a set of sensors that can tell when the vehicle’s actual turning radius doesn’t match the degree of turn the driver demanded with the steering wheel.
“If the car is exceeding the tolerances set up when the wheel was turned, it takes control of the throttle and closes it down to reduce speed, then applies the brakes in the proper sequence to pull the car back into the proper turning arc,” said Glenn Holmes, technical coordinator for Lexus, Toyota’s luxury division.
A few thousand measurements are taken and decisions made in doing all that, and the system does it far faster and with far greater accuracy than most humans can manage.
All-wheel drive, which apportions drive power evenly to the front and rear wheels until it senses a drop in traction that requires more power to be delivered to one set of wheels or the other, is another system dedicated to ensuring that cars and trucks go where they are pointed.
It’s availability is still fairly limited, though a few sport-utility vehicles, all Subarus, some Audis and a handful of sporty cars such as the Mitsubishi Eclipse and the Porsche 911 offer it. And the jury is still out on whether consumers will take to it the way they have taken to ABS, Peterson said.
One handling improvement that has flopped--because the industry hasn’t been able to show a real need--is all-wheel steering. It was first introduced in the U.S. by Honda, which quickly withdrew it, and now is offered--probably for the last year--only on the 1999 Mitsubishi 3000GT VR4 sports car.
All-wheel steering does reduce a vehicle’s turning radius and makes it corner better. But it adds more than $1,000 to the cost and piles on a lot of performance-stealing weight. And engineers have developed such sophisticated independent rear suspension systems that most cars today have what amounts to passive all-wheel steering: The suspension allows the rear wheels to turn or flex slightly to follow the track set up by the front wheels.
Tires are what make it all work, and manufacturers spend millions of dollars a year developing tread compounds, sidewall or “carcass” materials and tread patterns to improve the ability of a few square inches of rubber to glue a ton or more of rolling iron to the asphalt under a variety of weather and surface conditions.
Much of the research is done on the racetrack, where tires are subjected to beatings the average motorist could never replicate.
The absolute best tire for a dry, sunny day on a clean, straight asphalt road is a slick, with no tread at all, said Mark Richter, Yokohama Tire Corp.’s performance market manager. The more rubber on the road, the better the grip.
The tire makers’ challenge--especially because most people buy tires as much for appearance as for performance--has been to develop tread patterns and rubber compounds that work together to provide maximum “stick” while shedding debris and water that come between the tire and the road.
The result is a variety of tires, original equipment and replacement, that runs the gamut from long-lived all-weather models, which are serviceable in most ordinary driving conditions, to short-lived ultra-high-performance models that wear out in 6,000 to 8,000 miles, cost $500 or more apiece and help hold screamers like Corvettes, Ferraris and Porsches on the pavement.
Times staff writer John O’Dell can be reached via e-mail at john.odell@latimes.com.
