Thump-thump, thump-thump.

Bonnie pulled her Mustang over and stopped.

My daughter was supposed to be at her Lawrence High School sophomore girls’ basketball game in 15 minutes. And there was snow all over the road.

After a flurry of cell phone calls to mom and AAA Auto Club, Bonnie, her Mustang and a doughnut spare tire finally got to the game.

“You’re going to have to take care of it Saturday,” my wife told me when I joined her in the bleachers as the second half began.

As I watched Bonnie’s twin, Julie, bring down a rebound, I wondered how good Bonnie’s other tires were.

UNI-T technology

“Yeah, see how it’s all worn? You’re going to need two,” the guy at the tire shop told me after inspecting the other rear tire.

Scanning his computer screen, he found a couple of Daytona 16-inch tires in stock that would fit. Technically, they were P225/55R16 94H tires, rated A for traction, A for temperature and 400 for wear.

Not wanting to have a repeat flat in another month, I agreed to get both tires.

As I waited, I started reading the tire brochures in the showroom.

I noticed the letters “uni-T” were partly encircled in red with a line underneath saying “Ultimate Tire Technology.”

Bridgestone’s UNI-T technology

When you’re looking at how Japan’s Bridgestone/Firestone company makes its tires, be prepared for an alphabet of acronyms: UNI-T, UNI-T AQ and UNI-T AQII.

UNI-T is short for Ultimate Network of Intelligent Tire Technology. AQ stands for Advanced Quality.

The UNI-T works to maintain better wet braking and better wear. It has three core technologies.

In one, termed CO-CS (computer optimized- component system), computers are used to fine tune the tire’s shape and tread design to improve performance. For example, the shape and tread can be changed to make for better handling, or for fuel efficiency, or for comfort, or for tread life or even for less noise.

Two, O-beads have been designed to replace traditional beads. Beads are the hoop on the inside lip of the tire that attach to the wheel. Traditional beads have a cable that runs through them that overlap at the joint. O-bead technology eliminates that overlap, making the tire rounder, more stable and provides a smoother ride.

The third technology in the UNI-T group is called L.L Carbon. Carbon black molecules, which look like a bunch of grapes, are traditionally used to give the rubber more strength. The new L.L. Carbon process uses “long-link” carbon black molecules, which look like long chains, to dissipate the cracking energy, making tires wear longer.

The UNI-T AQ tires made by Bridgestone also offer two layers of “age-resistant” rubber compounds. These help your tires wear more consistently and provide consistent wet and dry handling as they age.

Bridgestone/Firestone also was an early leader in producing “run-flat” tires, producing them for nearly a decade. The latest is the new Firestone Firehawk SZ50 EP RFT model.

C3M technology

Michelin has a secret process for building its tires known as C3M.

It allows the company to exactly place three different rubber compounds on the tread. These different placements help to make customized tires at the factory for those who want improved performance on dry roads, or wet roads or roads with light snow.

The French company, which has 20 percent of the tire market, also has begun to showcase the PAX “run flat” tire. The tires, which run about $140 each, can go up to 200 km (124 miles) after losing all air pressure.

Michelin is teaming up with Goodyear on the PAX technology, which uses lasers to carve the design and create an asymetrical directional tread pattern.

The PAX run-flat system uses a specially designed wheel and insert. Goodyear pioneered the run-flat concept with its EMT (extended mobility tires), which it began offering in the mid-1990s.

Goodyear’s big technological breakthrough in recent years is called IMPACT, which stands for integrated manufacture precision assembly cellular technology. The mouthful means it’s a system to put out more precise tires more efficiently and cut labor costs. It uses a “hot former” to reduce the number of steps needed in producing a tire. That system is currently being used in Danville, Va.

Tire monitoring

Some companies also are working toward technology that monitors tire pressure while the vehicle is moving. One such company is SmarTire (www.smartire.com), which uses a sensor/transmitter that sends a message from inside the tire on the wheel to a display inside the car.

A weighty solution

After spending a couple hundred bucks and an afternoon learning about tires, I wanted some answers.

“So, you were just driving along and it just went flat? Did you hit a pothole?”

“I thought I hit a chunk of ice. Then I kept going and it started to smell,” Bonnie said.

“Thump-thump, thump-thump,” she said, when I asked what it sounded like. “I think it was because of my accident.”

The night before, she had fishtailed on a snow-slick roadway, making a 180-degree turn and jumping the curb. It was more of a slide-off than an accident. She thought the tire might have been damaged as it went over the curb onto the parkway.

Despite the new tires, it seemed like Bonnie’s rear wheel traction problems in the snow could be best dealt with a low-tech solution.

First, she’s going to get a lesson in tire pressure. And then there’s the weighty solution. What’s the sound four 50-pound sand bags make when they’re put in her trunk? You guessed it.

Thump-thump, thump-thump.

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