Inflating Tires


I heard on Car Talk how some mechanics inflated a flat tire by connecting a hose to a spark plug outlet and using the exhaust to pump up the tire:

1. Will this do long term damage to the rims or a new tire (a patched tire is unimportant I guess)?

2. If not, where can I get or how do I make one of these devices? They would be great for motorcycles and scooters and maybe I can toss the spare tire for a tire patch and a spark plug wrench? Smart Cars have a can of tire sealant instead of a spare tire. But a hose and a socket wrench seems less wasteful and doesn’t gum up the rims.

Wouldn’t it save gas for commuting or am I missing something?

This post has been moved to the new Car Talk Discussion Area, by a Car Talk Lackey. The original poster is 2020K.


Those inflators that connect to the battery are much more convenient and faster than getting dirty.


Before you toss the spare, have you considered how you are going to patch the tire? You have to dismount the tire to apply the patch and that requires some specialized equipment.

You’d be further ahead buy one of the those inflators with the sealant inside.

Besides, I think the point of the story is to test your resourcefulness - not to propose a method for inflating tires.


Years ago, such devices were available at Sears, Montgomery Ward, Western Auto and I’m sure many other stores. However, they did not pump directly from the cylinder. The compression of the engine on the cylinder being used operated a little air pump that used air from the atmosphere. I’ve seen these pumps in operation to inflate tractor tires in the field. Now I’ll admit that a battery operated pump would be more efficient. The problem with the battery pump is that some of the old tractors-for example a Farmall F-12 - had a magneto ignition and no battery. You hand cranked the tractor to start it. A battery pump wouldn’t do much good in this case. I’ve often wondered if one of these old pumps that worked off a cylinder could be used on a 2 cylinder John Deere. In any case, it’s important to remember that these old pumps did not pump the gas directly out of the cylinder, but that the compression stroke of the cyliner worked a pump that took its air supply out of the atmosphere.