Tire repair question

Factual Questions
#1

I park my car in an alley that is, unfortunately, often full of random debris. Recently, I found a large nail stuck through the thickest part of my tire tread (the tires are only a few months old and not thin at all–I had to replace them when I ran over other random debris previously…), causing it to deflate.

I repaired the puncture with Fix-a-flat (spare tire in a can), which sprays gook into your tire through the air nozzle and, one hopes, spreads evenly over the inner surface of the tire, solidifies, and seals the leak.

It worked OK, but the punishing roads in NYC soon popped the new seal. I found it flat one morning, and added another can of the gook so that I could get it to a garage for a professional patch job (I didn’t put on the spare b/c I didn’t have a free hour).

The guy repaired it, I presume, b/c it hasn’t deflated since. But now I have a new problem–the car shakes like hell once it gets above 55mph.

My father-in-law (a former amateur race car driver/mechanic) took a ride with me and said that it felt like the rear wheels were unbalanced. So I took it in to a Pep Boys (the only garage open on a Sunday) and they said that they couldn’t balance the wheel b/c there was liquid inside the tire–the fix-a-flat goop, which never congealed. They said they couldn’t remove the liquid, b/c the puncture might then not be sealed. I was too tired to argue or think clearly, so I left.

Back to my father-in-law, who says that a mechanic should be able to simply remove the tire, scrape the goop out, and (since it’s been patched) it should be good as new.

Is this true? Is this possible? How the hell are car tires constructed, anyway? I’ve never had one open, but I had always presumed that they just had a separate innertube like a bicycle. Can’t they replace the tube? My father-in-law thinks not–that tires nowadays have an integrated tube of some sort. I don’t get it. Can anyone explain to me (or point me to a Web site w/ diagrams, etc.) how a tire is built, and what would be involved in fixing my problem?

#2

Modern car tires do not have a tube. They seal along the inside of the rim. Any reputable tire place should be able to break the bead (or seal), open up the tire and clean it out. You need a tire machine (a big tool) to do it right, but it should only take a few minutes. Go to a tire specialty store and they should do it for you.

#3

I can tell you that automobile tires no longer have seperate tubes, and haven’t had them for years. The tire fits flush against the metal rims, and the pressure of the air in the tire makes a tight seal and prevents the air from leaking out. As to whether your father is correct about the goo-scraping, I couldn’t say. I would call another mechanic and ask him or, failing that, call the Car Talk Guys on NPR. They might not have the answer either, but I’m sure it would be a hilarious call.

#4

After the first use of Fix-A-Flat, you should have proceeded to a good tire service center and had the tire dis-mounted, cleaned and a vulcanized pacth applied from the inside. Anything else is a temporary fix. Virtually all passanger and light trucks today use tubeless tires as explained by hoopster

#5

many thanks, hoopster and others.

#6

If the tire has been plugged rather than patched, and you use fix-a-flat or a similar product, extra “goop” WILL collect around the plug causing your tire to be off balance, thus the shake.

As stated, a reputable tire shop should, if you tell them the situation, be able to remove the tire from the rim and clean out all the “goop” restoring the tire to its normal balance. It sounds like the place you took it to simply did not want to mess with it.

#7

Inner tubes are still available at your tire dealer, and can make a cost-effective fix for tires that still have a lot of tread but have had a puncture history. They also are a cheaper fix for a slightly bent rim, which will also cause leakage.

My neighborhood tire guy has put a couple on for me.

#8

[hijack] I have had to use tube tires on occasion because I used to drive a few older rally cars (MG-TC and an MG-TD) and they had spke wheels with knock-off hubs (points to anyone who knows what those are.). I know they do still sell tubes in most sizes, but it is not all that common that you can take your Vette in and get tubes that would work in your 220 x 50 R17 tires. [/hijack]

#9

I asked the Dopers about Fix-A-Flat a while back.