Alpinestars

When Jorge Lorenzo, the Yamaha factory racer, was catapulted from his bike in a crash while practicing at Laguna Seca on July 22, sensors in his suit read that he hit the pavement with the force of 25.3 Gs. It’s the kind of impact that can shatter bones and careers, but Lorenzo not only walked away from the crash, he placed second at the track two days afterward in the Red Bull United States Grand Prix.

Alpinestars

His speedy recovery was attributable in part to a protective suit with built-in air bags. The suit, which has undergone track testing since 2007, recently became available commercially in Europe for the equivalent of $8,500, more than twice the cost for a comparable suit without the protective technology. Alpinestars, the motorcycle apparel company producing the suit, expects to sell it in the United States beginning next summer.

There is at least one more air-bag suit on the European market, from Dainese. Andrea Onida, a spokesman for the manufacturer, said there was no plan to bring the design to North America, which went on sale in Europe this spring.

Spread throughout the Alpinestars Tech Air Race Suit are five accelerometers designed to sense the rider’s body position, speed and direction of movement. The tricky bit involves programming the accelerators to distinguish between a hard-cornering racer from one who becomes separated from the bike.

“The way we sense that is proprietary information that we don’t divulge,” said Tim Collins, a spokesman for Alpinestars, in a telephone interview.

The sensors are checked every two milliseconds by a central processor stored in a hump sewn onto the suit’s upper back, measuring roughly the same size as a household’s double-light-switch plate. If the processor triggers the air bag, it takes 45 milliseconds for a cylinder of nitrogen gas to inflate the shoulder and collarbone protection, typically 100 milliseconds before rider meets pavement, according to Alpinestars’ research.

The bags remain inflated for five seconds. A second nitrogen charge is held in reserve in case of a second crash. Alpinestars claims that the batteries that run the system are good for eight hours of riding.

The crash-detection system is considered active when it senses that the rider is seated on a motorcycle and moving. But the suit would not be activated unless its main zipper was closed. Opening the zipper puts the suit in a stand-by mode, which is intended to reduce the chance of accidental inflation. LEDs on the suit’s sleeve inform the rider of the system’s status.

Made entirely of leather, the suits come in size 38 to 46 and in three color combinations: black and white; black, white and red; and black, white and yellow.

Mr. Collins said the suits were cleared to be sold in the United States, but the introduction was staggered behind Europe while the company increased its production capacity. They are available there in select shops, with a wider unveiling planned over the next two months, he said.

According to Mr. Collins, the bags deployed on the track in major races 36 times in 2010 and 2011.