donuts are for eating, not for driving.

November 26, 2006 12:24 PM

one of my tires on my car goes flat every 4-6 months or so. it's a different tire each time. what could possibly be causing this?

i drive a 1998 saturn sl2. i've only owned the car for a little over 2 years, but there has been lots of work done on it in that time.

aside from the numerous mechanical issues, i've noticed something weird. every few months, one of my tires will go flat. at first, i thought it was due to the age of the tires. so each time a tire went flat, if it couldn't be patched, i had it replaced. unfortunately, none of the tires were able to be patched. and now i'm starting to replace tires that i replaced a year ago.

currently, my rear driver's side tire is flat. before that, it was the front driver's side tire. before that, it was the front passenger side. you get the idea.

i'm not driving over broken glass and nails on my way to work every day. my commute is really short -- less than 5 miles, on city streets (1 block of my commute is on a brick road). i park in a parking lot that is free of debris. when i'm at home, i park on the street in front of my apartment building, along with everyone else. i rarely park in the same spot every day as other people beat me to it. my boyfriend parks on the street too and his tires never go flat (lucky punk). as far as i know, i don't have any enemies that would want to destroy my tires.

is there anything else that would be causing my tires to go flat? or am i just unlucky?

posted by kerning to travel & transportation (14 comments total)

Do you annoy the folks next door with loud music? Is a co-worker at work is trying to kill you? Perhaps there are social, as well as mechanical explanations.
posted by tiamat at 12:29 PM on November 26, 2006

What do the people who replace your tires say seems to be the cause of the flats? They ought to be able to tell if the tires are worn down or have been punctured by something, and, if so, by what kind of thing.

If the tires are wearing down that quickly, your tires are probably not aligned correctly. Improper alignment often produces uneven wear. You should get that checked, as well as have your tires rotated every couple of months, to help even out the wear even better.
posted by cerebus19 at 12:31 PM on November 26, 2006

Could be a bad seal around the inside of the wheel, due to paint or roughness. Could be the valve stem, although they should replace these with the new tires. Work from the cheapest fix to the most expensive. Replace the valve stems.
posted by weapons-grade pandemonium at 1:23 PM on November 26, 2006

How often do you check the pressure on your tires? It should be done at least every two weeks as air naturally escapes unless you're using nitrogen in your tires. Also the PSI for your tires may need to be adjusted between summer and winter (check your owner's manual). Depending on what kind of vehicle you have and if you use a trailer the pressure on front tires may be different than that of the rear tires. Again, it's in the book. Incorrect pressure can cause additional wear on your valves that could cause leakage, and unatural wear on your tires. I also recommend getting your wheels rotated.
posted by furtive at 1:46 PM on November 26, 2006

I agree with weapons. A slow leak is usually a bad valve stem or a bad bead seal around the rim. You can test the valve stems by removing the cap and putting some soapy water over the end. If you see a small bubble forming over a few minutes time, then you need to replace the valve stems, which cost about 10 cents each. You can do the same bubble test on the rims, but it means taking the wheel off the car and laying it flat on the ground to test both sides.

On the other hand, 4 to 6 months is a long time. Most tires will lose air over that amount of time. As a friend says, you just need to "fluff up" your tires once a month.
posted by JackFlash at 1:52 PM on November 26, 2006

Please come back and tell us more about "goes flat" and "couldn't be patched."

If the tires go flat because they are punctured:

If the punctures are always in the side of the tire, then somebody is doing it. If you tend to bump against curbs, the somebody is probably you. If it isn't you, someone doesn't like you.

If the punctures are in the part that touches the road, you're driving over nails or screws. (Many of those holes can be patched, but a lot of people say they shouldn't be.) Roofing nails and drywall screws are the most common and effective tire-biters, and roofers are known for being casual about depositing and cleaning up old nails. Try to avoid the driveways of houses with new roofs or new interior walls.

If the tires go flat without being punctured:

The most common cause is corrosion on the wheel where the tire sits, or where the valve stem goes through the wheel. (The stem is the rubber post you can see; the actual valve is hidden inside the stem.) Bad valves could also make a tire go flat, but I don't think I've ever seen it.

The someone who doesn't like you could also be loosening the valve, which would act like a leaky tire.

posted by Kirth Gerson at 4:39 PM on November 26, 2006

When you need to get a flat fix, find a local reputable place to get the tire reparied and ask them how the tire went flat. I had a series of these things happen to me earlier this year with my 1998 car as well. Turns out it was the bead seal that was mentioned above. The aluminum rims on my car built up enough corrosion and gunt that the tires were having a hard time maintaining a good seal. The cool thing was that the fix was to buff down the corrosive spots and to apply a thick coat of the black bead sealent before inflating the tires again. The cool thing is that this place never charged me a penny for any of this.
posted by mmascolino at 5:00 PM on November 26, 2006

I went years without a flat, and then they started renovating the apartments where I live. Bam, two flats in three months. One was repairable, one was not.
posted by kindall at 5:34 PM on November 26, 2006

You can fix this simply by putting tubes in your tubeless tires. They might build up heat a bit more, but only if you're running high speeds in hot weather.
posted by weapons-grade pandemonium at 6:43 PM on November 26, 2006

I'm tipping that one of your wheels has a valve or bead sealing issue, and that the flat moves around your car as your service person rotates the tyres.

Next time it happens, put a little scratch somewhere unobtrusive on the wheel itself (not the tyre) and see if it's always the scratched one that goes down.
posted by flabdablet at 9:05 PM on November 26, 2006

I've had this, and I always make them wire brush the crud off the inside of the wheel, and put in a lot of sealant, and it quits. Sorry, not familiar with your climate, but drastic changes in temp can also do this, if you get those. It's common to have one or more go soft when the seasons change in our area.
posted by unrepentanthippie at 4:47 AM on November 27, 2006

Costco sells good tires, and their tire personnel know what they're doing. They torque all the wheel bolts twice, and once your tires are installed, you'll never again pay for flats, rotation, or balancing. They even put 100% nitrogen in your tires. I have no connection with them; I just like their tires and tire service, and I'm picky.
posted by weapons-grade pandemonium at 10:01 AM on November 27, 2006

It's not out of the question you're being bilked/milked.
posted by weapons-grade pandemonium at 10:02 AM on November 27, 2006

thanks for all your answers!

i'm not really very car-knowledgeable. i tend to just give my car to mechanics and tire experts and let them take over. i'm kind of shy so i don't ask a lot of questions -- i just pay the bill and go. so i don't know if the tires were punctured.

this last time, it was a very slow leak. it went flat over a period of 3 days. the 2nd day, i filled it up with air thinking my tire was just low. the next day, the tire was flat. the other times, the tire would go flat overnight.

i usually go to a local mechanic -- one whom i've been going to for all my car problems. he's very reputable, and is one of the best mechanics where i live. i plan on taking my newly flat tire to him on friday and i will ask if it was punctured.

i go to college in west virginia (marshall university) and the climate does change, though not necessarily drastically. however, lately, we've been having temperature fluctuations, so maybe that has something to do with it.

i'll also have the bead seal checked out -- that sounds interesting and quite possibly the problem.

seriously, again, thank you all for your answers. i really appreciate it. :)
posted by kerning at 1:11 PM on November 27, 2006