How to fix a flat
February 21, 2011 8:57 AM   Subscribe

What's the cheapest (safe) way to take care of a leaking car tire?

One of my car tires has been slowly going flat. I filled it with air last week and within a couple days it was looking dangerously low again. I've got to take care of this today.

I'm on a very, very tight budget. It's my understanding that the "right" way to do this is to replace all four tires with new ones, so they are all the same type and will all wear evenly. I can't afford to do this, so what do you recommend? I'm thinking I should just buy a single used tire as a temporary fix, then in a couple months when I have more money available replace all four. Is this a bad idea?

What else could I do? Could I have someone find and patch the leak on my existing tire? That would probably be even cheaper, which is critical at this point in time. What else should I know about my options? What kind of shop should I go to? I've never done this before. Though money's in short supply right now, I don't want to be so cheap that I risk damaging my car somehow, or making it unsafe to ride in.

If it makes a difference, the car is AWD; I'm not sure if/how that affects the tires.
posted by The Winsome Parker Lewis to Travel & Transportation (25 answers total)
If it's got a puncture in the tread (like a nail stuck in it or something similar), you can take it to a service station and get it patched for about $6.
posted by tylerkaraszewski at 8:59 AM on February 21, 2011 [3 favorites]

I have nursed a tire along for months on a can of Fix-a-Flat.
posted by brownrd at 9:00 AM on February 21, 2011 [1 favorite]

Often if you need to get this taken care of and you can't afford new tires, you should first try seeing if you can get the tire repaired. Some sorts of tire injuries are repairable and some aren't. So, for example, if you have a leaky valve or a nail in the tire, these are things that a competent tire shop could fix and it would cost $5-20.

So, call a place that does tires and say "I have a slow leak and I'm wondering if you guys do tire repairs?" and then go from there. If you have a real tire problem like a sidewall leak then yeah, you're going to need a new tire. It's always better to get a pair of new tires rather than a single, but you do what you can do. Also make sure you don't have a perfectly good full sized spare. If you do, you can have that tire mounted on the car and possibly get the old leaky tire repaired and then used as a spare tire.
posted by jessamyn at 9:01 AM on February 21, 2011 [1 favorite]

I am not a mechanic and I don't even know anything about cars really, but my fiance had a problem with two of his tires going flat, and he took it to a Mr. Tire. They told him that it was the valve stems, not the tires, so they replaced both the valve stems for like $50. So I guess what I'm saying is: Are you sure that you need to replace the whole tire?
posted by specialagentwebb at 9:05 AM on February 21, 2011

Expanding on specialagentwebb, leaking valve stems are very common and very often you can replace just the core, an easy DIY job. Remove the valve cap and put a little liquid into the end of the stem. See any bubbles? If yes, your core is leaking. Go to your local auto parts store and buy a new stem for around a buck and get a valve stem remover cap (less than a buck).

Go somehwere with tire inflation equipment and VERIFY YOU CAN REINFLATE THE TIRE BEFORE PROCEEDING!!

Unscrew the old valve core by using the remover tool.
Install the new core
Reinflate the tire
Test to see if it still bubbles
posted by buggzzee23 at 9:18 AM on February 21, 2011 [1 favorite]

I forgot to mention remove the core from the new stem and use it as your replacement core
posted by buggzzee23 at 9:19 AM on February 21, 2011

This is why I love AskMe. I don't know diddly about tires but you guys give me hope. :-) Thanks, I'll post back here later with what happened. Feel free to keep posting advice in the meantime.
posted by The Winsome Parker Lewis at 9:19 AM on February 21, 2011

You can't know how to fix it until you figure out where the leak is.

If it's a puncture in the tread, you can extract the nail or screw and plug it with a kit you'll buy at an auto parts store, or have a garage do it. The garage will do a better job, and charge a little more.

If it's a leaking valve stem, the valve stem must be replaced. This should cost way less than specialagentwebb's fiance paid.

On an older car, the leak could be cause by corrosion of the rim, causing a leak where the tire [fails to] seals against the rim. Here the tire must be removed, the corrosion cleaned up, the tire remounted and rebalanced.

If there's a hole in or very close to the sidewall, the tire is toast. Your best bet there is to buy two matched used tires, as the tires on a given axle must match.

Generally, I'd suggest you avoid big chain garages if possible. In my experience, they're more expensive than independent shops.
posted by jon1270 at 9:20 AM on February 21, 2011

BTW, the first thing the garage is likely to do is to take the tire off the car and swab it with soapy water to see where it blows bubbles from. You could do that yourself if you felt so ambitious.
posted by jon1270 at 9:22 AM on February 21, 2011

Any shop that sells used tires will most likely offer patching services. Go in to your local tire shop (mom-and-pop, not Corner Tire Chain) and ask for X tire to be patched. Stating clearly what you want shows you are moderately car-savvy and know what the issue is.* If there's anything more serious, they'll tell you, but most of the time you'll be on your way in 15 and about $7 lighter. Those shops also sell used tires starting around $40. It's not a huge deal to replace all four of your tires immediately with brand new ones, unless you've got $300 sitting around and treads sticking out of the rubber.

*I only mention this because some business owners tend to prey on the ignorant.
posted by therewolf at 9:25 AM on February 21, 2011

Tires can safely be patched if the hole is small (like from a nail) and in the tread. This is pretty cheap as mentioned above. You can find the leak by making some soapy water, taking the wheel off the car, and putting the soapy water on the whole tire (try to make as little bubbles as possible). If it is in the tread, the tire shop guys will unmount your tire, remove any remaining pieces of debris and install a mushroom patch. A very slow leak will just make a little bit of foam, while a bigger one will make bubbles.

The valve core can also be loose; The little valve that keeps the air in the tire just screws in, and a tool to re-tighten the core should be available at wal-mart for less than $10.

The wheel itself could be leaking as well, but this usually only happens on cast Alloy wheels. This is more expensive to fix.
posted by ArgentCorvid at 9:31 AM on February 21, 2011

Just to reiterate something ... If you must buy a new tire, you can buy two, not four, on the same axle. Nothing wrong with that plan. And put the two new ones on the axle getting the power (e.g. front, for a front wheel drive).
posted by Cool Papa Bell at 9:34 AM on February 21, 2011

It's my understanding that the "right" way to do this is to replace all four tires with new ones, so they are all the same type and will all wear evenly.

Absolutely not. In no way at all. If you have a tyre that wears out, it is better to replace an axle set (ie both fronts or both rears) but certainly not all four. If I have something like 50% or more life left on the tyre on the other side, though, I'd sure as hell not replace more than one. Given the option (ie if money is not so much of an issue) then one pair at a time is better though.

Repairing a tyre is perfectly valid, just make sure you never, ever drive on the tyre when it is flat or nearly flat - it damages the sidewall and will weaken it (increased chance of blow out). It's possible a slow leak is teeny hole (perfectly repairable) a fault valve stem (perfectly repairable) or even just corrosion on the rim preventing sealing where the tyre meets it (cheap and easy to repair also). Take it to a repair shop and ask them to fix the leak.

They should be happy to do this unless the fix isn't possible or in a dangerous place.
posted by Brockles at 9:34 AM on February 21, 2011

Oh, but you have AWD. Put the new ones on the back.
posted by Cool Papa Bell at 9:35 AM on February 21, 2011

My mechanic plugged a hole two weeks ago for free, and apologized that he didn't put it back on, too! Of course, this is predicated on our taking him all of our auto repair work for years now -- and if you're in a hurry and on a tight budget (my sympathyies), you probably don't have a regular mechanic.

Something to think about for the future, I guess. Good luck!
posted by wenestvedt at 9:45 AM on February 21, 2011

Like the others have said take the car into a shop and have them give you an estimate to repair. The estimate will probably be free and the fix could be a cheap as cleaning the bead (IE: ~$10).

If your tire isn't repairable (pretty well the only reason it won't be is a separation or a puncture in a side wall) you can try phoning around to auto wreckers and see if you can find a match. Often you can buy a used mounted tire on a steel rim for for less than the cost of either individually. In a pinch when I've been really broke I've even compromised on finding the exact same tire as long as the manufacturer and size was the same. Observe the operation warnings for those ridiculous temporary spares and you'll be fine.

And put the two new ones on the axle getting the power (e.g. front, for a front wheel drive).

If you are replacing only one axle and all your tires are the same size then new tires should be installed on the rear axle moving the worn set to the front. Over steer caused by the rear breaking loose is way more dangerous for the average driver than a lack of traction at the front.
posted by Mitheral at 9:54 AM on February 21, 2011

National Tire and Battery, Walmart, Sears, Discount Tire - just a few of the national chains that hopefully are close to you.

All you'll need to do is swing by (NOT at lunch, pick an off time) mention the leak and they'll take a look at it and possibly patch for free. I've never felt pressured, just tell them your story and that you really need to get out spending as little as possible if the tire can't be repaired.
Good Luck!
posted by doorsfan at 9:58 AM on February 21, 2011

Umpeenthing getting a patch.

Avoid like the plague stuff like Fix-a-Flat, unless you are using it in order to keep the tire inflated just long enough to get to a store to replace it. Never use Fix-a-Flat as a long-term fix.
posted by Thorzdad at 10:35 AM on February 21, 2011

Patch it or fix the valve and, if you can't, just replace the one tyre with a part worn for ~$30 and move them around so the wear is as even as possible per axle.
posted by turkeyphant at 1:46 PM on February 21, 2011

I have had good luck with Fix-a-Flat. It helps until you can either get the tire repaired or replaced. Garages with mechanics, if you can still find one, will patch a flat tire very cheaply. Or just go to a tire place and ask them to patch the tire. If the wall is bad, then you really will need a new tire. But you can just get one, and then get another one for that axle when you can (sooner better than later.) They will try to pressure you into getting two tires, but if you cannot afford it, then don't.
posted by fifilaru at 1:47 PM on February 21, 2011

Nthing the hope that you can get it plugged; I was wary of plugs, got a nail in a nearly new tire (when I was far from waist-deep in money), the tire guy said the plug would be fine and it lasted for years.
posted by ambient2 at 2:42 PM on February 21, 2011

There is a difference between a plug and a patch. Plugs are stuck in from the outside and are a temporary make do until you can get to the shop. Patches are applied from the inside (the best are mushroom shaped with the stem sticking through the hole. A patch applied soon after a puncture (before exposed steel belts can degrade) is essentially as good as the original tire. Driving on a plug is just asking for trouble.
posted by Mitheral at 3:24 PM on February 21, 2011

Thanks, everyone, for the help. I took the car to a local shop... they removed the wheel and quickly found the problem. A pebble had gotten caught in the tread and caused a puncture, but still mostly sealed the hole. As soon as the mechanic took the pebble out, air started escaping the tire with a loud hiss. He was able to patch up the hole and send me on my way in about ten minutes, for about ten dollars. It was a painless experience all around. :-)
posted by The Winsome Parker Lewis at 7:37 AM on February 22, 2011

Also, I'm really glad I didn't try to find and remove the pebble myself, as that would've left me stranded at home with a completely flat tire. Much better that was taken care of at the mechanic's, since I still had enough air in the tire to drive there.

They also put a new cap on the valve stem for free, since I was missing one. I thought that was a nice touch.
posted by The Winsome Parker Lewis at 7:40 AM on February 22, 2011

Score! Very glad you had such a happy outcome.
posted by DarlingBri at 3:56 PM on February 22, 2011

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