Bob Toth has a lot of faith in the "geniuses in the electronics industry."

The folks who gave us a $10 calculator, he figures, surely can produce a low-cost sensor that alerts drivers to an impending flat tire.

Several companies already have developed the sensors that are essential for so-called "run-flat" tires - the ones that can drive long distances (up to 200 miles [322 km] on Corvette) without air. A sensor mounted inside the tire signals a receiver in the cabin when it detects low air pressure, giving a driver a better chance to reach a repair center before having to pull out the jack.

Every tiremaker is developing run-flats, with great expectations for an exploding market. Michelin's Zero Pressure run-flats are available on Lincoln Continental and now the BMW 7 Series. Goodyear's Extended Mobility Tires (EMTs) are standard on Corvette and Plymouth Prowler and will be available on the new BMW 540i coming out this year.

Goodyear says it has identified heavy consumer interest through research and predicts that up to 70% of its tire production could be devoted to EMTs by 2003.

But that optimism depends on steadily falling prices for sensor units. Goodyear's run-flats cost about 20% more than comparable conventional radials, but the sensor system adds a consumer price of between $250 and $399 for a set of four tires - a tad pricey for even the most safety-conscious motorist.

That's why Mr. Toth, marketing manager for Good-year's performance tire unit, is confident that sensor suppliers, eager to cash in on a potential goldmine, will come up with low-cost options for $50 a set, or less.

And Mr. Toth doesn't expect one technology to dominate. At a quarter of its North American retail outlets, Goodyear offers sensors from SmarTire Systems, and just recently it approved for sale a simpler and less expensive unit from valve stem producer Schrader-Bridgeport.

"All we want is to say it's approved for use with Goodyear tires," Mr. Toth says. "Then the market's theirs. They can sell to the retailers directly."

The sensor suppliers, besides SmarTire and Schrader-Bridgeport, include Dunlop Tire Corp., Continental Teves AG, TRW Automotive Electronics and Johnson Controls Inc. (JCI).

Expect to see some of these suppliers, and maybe more, displaying sensor systems at this year's Society of Automotive Engineers International Congress & Exposition early in March at Detroit's Cobo Center.

TRW will display the TireWatch system it developed with Vancouver-based SmarTire Systems, a pioneer in tire-pressure monitoring. TRW considers TireWatch the next-generation pressure sensor, offering simple installation options and black-box recording capabilities to address liability and warranty issues. TireWatch also can be used with conventional radials.

Most significantly for TRW, TireWatch can operate on the same radio frequency and transmit to the same receiver as key fobs for remote keyless entry (RKE) units - already a hefty chunk of business for the electronics giant. Tire information is communicated to drivers through a display on the rear-view mirror.

Mark Desmarais, marketing director for TRW's Automotive Electronics Group, says dual-use of the receiver can save an OEM more than 20% per vehicle. TRW will launch TireWatch in the aftermarket later this year and has tentative OEM launches scheduled for '01.

TRW isn't the only supplier proposing to link vehicle electronics with tire sensors. JCI introduces its Pressure Safety Information system, which debuts in several 2001 luxury models and can be integrated with JCI's HomeLink electronic communications system linking vehicles to home security and other conveniences.

In a unique position is German tire maker Continental AG, which is launching a run-flat tire this year and another next year. After its recent acquisition of ITT Automotive's brake business, Continental has the potential to eliminate the pressure sensor altogether by using its antilock brake software to detect a soft tire.

Now if only these sensors were as cheap as a calculator.