HowExhaust Air Jacks Work

If you've ever had to change a tire in the middle of nowhere on the shoulder of a gravelly road, you might consider the exhaust air jack a dream come true. These automotive gadgets make the arduous task of lifting a car off the ground far less painful and awkward -- simply by letting the car's own exhaust do the dirty work.

Traditional portable jacks, like the ones that come with your car, can be intimidating to the uninitiated. They have to be placed at a certain point on the chassis for safety, then fitted with a bar for leverage and cranked up, and up, and up. It takes a bit of strength and a lot of patience -- qualities most drivers find in short supply when a tire goes flat.

The exhaust air jack lifts a vehicle using emissions coming from the tailpipe. A hose attaches from the exhaust to a big sack placed under the car. The air coming out of the pipe fills the bag, and voilà! The car lifts off the ground.

These gadgets stay inflated for as long as 45 minutes, though you should keep in mind that your car will be idling and using gasoline that entire time. Air jacks come in different sizes and capacities and can lift vehicles as far as 30 inches (76 meters) from the ground. Exhaust jacks deflate in as little as five seconds when the job is finished, and the PVC-coated woven canvas folds up to fit in your trunk until you need it again.