how to fix a very slow tire leak?

Discussion in 'General' started by MT bucket, Jun 11, 2009.

  1. MT bucket

    MT bucket I want my MPG!

    I have my tires on my pickup at 60 psi ( higher than recommended here I know) but I like the lower rolling resistance and actually like the feel of sensing every little crack in the pavement. it also makes me more diligent about avoiding potholes.
    anyhow, after a couple of days my left front will be down in the 50s and after a week the 40s. any good way to fix this? i would prefer not to have to go to the filling station every day to top it off.
  2. hunter44102

    hunter44102 Well-Known Member

    Try this:

    Remove wheel, fill to 60PSI and put in small tub of soapy water.

    Spin the tire slowly in the water and look for bubbles/air.

    Once you find the leak, mark and use one of those $5-$10 plug kits at any parts store

    This is how the gas stations do it.

    If the leak is on the sides it cannot be plugged. If its a rim leak, I think they might have to re-install the tire
  3. CapriRacer

    CapriRacer Well-Known Member

    First you need to find out where the leak is. There are several possibilities.

    1) Normal passenger car tire valves are rated to 60 psi. However, as time goes on, they may develop some seepage, either though the valve core itself, or where the rubber in the valve contacts the rim.

    2) Alloy rims are essentially a loose cystalline matrix and are naturally porous. As a result ALL alloy rims are clear coated - partially to maintain their appearance over time, but mostly to seal those pores. Over time the clearcoat can be rubbed off or crack (miscroscopically) and allow air to escape through the metal matrix.

    3) Alloy rims also corrode when in contact with steel. It is fairly common for the steel clips that hold the balance weights on scratch through the clear coat and corrode the alloy.

    4) You may have a pinhole (or worse) leak somewhere in the tire. Needless to say, using higher pressure will not only force the air out more rapidly, but the tension on the tire due to the pressure will expand the hole more.

    There are other scenarios.

    So you need to find the source of the leak.

    One way is to use a soapy solution in a spray bottle. When sprayed onto a leak, the solution will bubble where there is a leak. However, this will not work for leaks that are slow or from a large area - like the alloy rim porosity would be.

    In those cases, immersing the tire in water is more effective. Kiddy pools work very well for this purpose, but the tire / rim has to be weighted down to keep it from floating. The problem is that you have to take the tire and rim off the car and it sometimes takes a few hours for the leak to become apparent.
  4. Taliesin

    Taliesin Well-Known Member

    Another option (that my room mate would kill me for making) is a can of fix-a-flat. It would seal any small leaks, but you will have a heck of a time getting the tire off when it comes time for new ones.

    EXPIOWA Man of Leisure

    Take it to the tire store and have somebody do it for you. It is the easiest and most reliable way. I believe Discount Tire will do it for almost nothing. I wouldn't mess around with it.

    Btw you are not gaining that much from over-inflating. In my opinion it is foolish, and definitely dangerous. You could even be considered negligent in a crash by exceeding the posted limitations of your tires. If you keep doing it I will make sure that they put how many gallons of gas you saved on your tombstone.
    Last edited: Jun 11, 2009
  6. ksstathead

    ksstathead Moderator

    ...yet I keep wondering how I survive on my road bike at the recommended 145 psi.

    EXPIOWA Man of Leisure

    Maybe it's because that is the recommended pressure. No limitations have been exceeded. Pump it up to 200 and let me know how its going next fall.

    Hypermilers are quick to say that AAA is wrong about how safe hypermilers are and we have a Dangerous Drafters thread. I think we should have a Dangerous Over-inflaters watchdog thread as well. It is proven that over-inflating decreases your margin of safety.

    You all probably already think that I can be a jerk but this has to do with safety and I will not apologize for that. Even if you didn't crash you can buy a lot of miles for the price of one destroyed tire even at $4/gallon.
  8. ksstathead

    ksstathead Moderator

    Define overinflation, giving examples of ...what? crashes, exploding tires, extended stopping distances, increased/uneven wear?

    At the pressures we run we are seeing the opposite. Granted we don't operate at the edge of the tire performance capability, where such things MIGHT show up, but that is part of the point: We drive slow, pay attention, and see BETTER handling, wear, performance.

    The ride is stiff, but again, we are not psl+10.

    I welcome your perspective; keep it coming.
  9. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    Show me an example of tire failure due to overinflation.
  10. digidug

    digidug Well-Known Member

    Questions to research before jumping to conclusions about safety:

    How much margin of safety is built into that max sidewall rating?

    How much are we decreasing it by over-inflating by say 15%?
  11. MT bucket

    MT bucket I want my MPG!

    Thanks for the tips everyone. i think I am going to go with EXPIOWAs and just take it in to a tire store, i don't want to deal with removing the wheel, etc...;)

    Thank you for raising the safety concerns regarding high tire pressures. I drive for a living so that is very important to me. I read this article and that changed my mind about tire pressure.

    read it and let me know what you think.

  12. nervousmini

    nervousmini Well-Known Member


    Don't ever use that stuff unless you are really stranded and have no other options. I have had to work on tires after this stuff is installed and the mess it makes is unreal! They also usually use PROPANE or ISOBUTANE or some other typically flammable/explosive gas as a propellant - not fun when you're the guy that has to hope you don't spark anything as you are breaking the tire down.
  13. run2w8s

    run2w8s Active Member

    Had a slow leak on a Sienna minivan with alloy wheels. Turned out to be corrosion along the bead. Shop removed the tire, cleaned off the corrosion, problem fixed.
  14. drimportracing

    drimportracing Pizza driver: 61,000+ deliveries

    Yesterday I went down a gravel road for about 1 mile and upon leaving I noticed my passenger front was going flat fast. I got to the end of the gravel road and pumped it up somewhat until I could find the hole, it was a tear between the treads caused by a rock, I plugged it with 2 plugs and went into town, calling ahead to the tire store, $36.00 and I was back on the road in an hour.

    I believe that if I had 35psi when I went down that rocky road I would have had a much better chance of not busting a tire. I will continue to keep 60psi in my tires unless I have to go country driving again and then I'm deflating for the trip. Stuff happens. :D - Dale
  15. Yaris Hilton

    Yaris Hilton Half a Bubble Off Plumb

    You really don't want to use Fix-A-Flat if you have a Tire Pressure Monitoring System.

    EXPIOWA Man of Leisure

    Third attempt to post this. My internet provider in this hotel sucks and I am posting from an ipod. I will create this post in stages then edit it to add more informaion.

    MT bucket, wise choice. Thank you.

    I second not using fix-a-flat. Some of that stuff is also flamable. It's nothing to worry about under most circumstances though. I just don't want that crud inside of my tires. Some service stations don't like having to deal with it. I have been to a few that charge more to fix a puncture if you used it.

    A previous reply was correct about a margin of safety being built into our tires. I will explain why you may exceed it and not know until it fails. For starters most people don't know how or when to inflate their tires. It should be done within the first mile of driving. After that tire pressure will be effected by the temperature of the tire. A tire is to be considered overinflated if you exceed the Max Inflation shown on the side wall of the tire itself. I have never seen one with the word "recommended". Like it or not that is how it is.

    If you fill your tires in the morning when it is 65 degrees then it gets up to 95 that afternoon your pressure will increase by 1 psi for every 10 degrees. Then you decide to go for a drive. Friction with the hot road will increase your pressure even more.

    Walk on blacktop with bare feet and you can tell that the temp can be signifficant. That adds heat to the tire again through convective heat transfer. As you can already see, your tires have to be safe over an already wide range of conditions. An overinflation of 15 percent can turn into much more.

    Now let's talk about the tire itself. They are not all the same. There is a world of difference between an H rated tire and a Z rated tire for example. A new tire may be able to handle overinflation for a while if it was built properly. Over time tires wear out. The tread blocks wear down and no longer provide the cushioning effect that they had when they were new. Now the core structure will take more abuse. Some tires have a softer compound that the tire wears into so that it maintains the same grip over the life of the tire as well. Did you know that a high speed rated tire looses it's speed rating if it has been patched? True, with very few excepions.

    Another thing to think about is the fact that your tires were built to a cost to accomidate the average driver under a certain set of conditions. I don't want to find out the hard way what part of my tires they decided to save a nickel on. Remember the Wilderness fiasco with the SUVs back around 2000? Believe it or not the failure rate of that tire was not that far from the average for all tires. The press jumped onto the bandwagon and went to town with it.

    Most of of do not have expansion resistant nitrogen in our tires and they won't stay new forever. Your tires were designed to provide a margin of safety over their entire serviceble life provided that their use falls into a specific set of conditions. Tire manufacturers have gone through a lot of trouble to design, test, produce, and market safe, low rolling resistance tires specifically for people like the ones here at this forum who's goal it is to maximize mileage. Please for the sake of those around you don't overinflate your tires. It is dangerous.
    Last edited: Jun 12, 2009
  17. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    Remember the Wilderness tire fiasco? I sure do. A major factor in that case was the Explorer's LOW recommended inflation pressure. Since that event, Explorers come with a higher recommended pressure. Why might that be?

    Nitrogen is a gas just like any other. It must obey the same pressure-temperature laws.
  18. Taliesin

    Taliesin Well-Known Member

    And that's the whole reason my room mate would kill me for bringing it up. It's definately not the best option.

    EXPIOWA Man of Leisure

    Why that might be is not that much of a mystery. Off road vehicles typically use a lower pressure to increase the footprint of the tread. I believe the auto manufacturer recommended around 28 psi, which is well below the pressure limitation set by the tire manufacturer. It will ride smoother and grip better when used off road, the purpose for which they were designed.

    Guess who drives most of these types of vehicles? I'll give you a hint, suburban moms who want the space and crash protection for their children and there is nothing wrong with that. The problem arises from the fact that these types are not doing regular checks on their vehicle's condition, if ever.

    Knowing that, if you were a service station owner who only saw the vehicle every 5,000 miles for the oil change wouldn't you want to make sure that the pressure would be sufficient until the next visit?

    People will sue for anything and Tires can loose around 5 lbs./month. It was a case of the manufacturer shifting the blame from their design to individual's improper maintenance. Starting from a higher pressure was a simple fix. We now have tire pressure monitoring systems that you have to pay for when you buy a new car because you can't trusted to use a tire gague on a regular basis.

    Btw, nitrogen is very different. It does not expand as much as regular air due to temperature or ambient pressure changes. It us used exclusively in large aircraft tires because it does not expand as the pressure drops with altitude. If you do some research you will also see that it is the gas of choice for inflating the tires of every elite form of auto racing. I don't think that you could even buy an exotic car anymore that didn't have nitrogen filled tires. It is that much better and it will not corrode alloy rims like air will.
    Last edited: Jun 12, 2009
  20. R.I.D.E.

    R.I.D.E. Well-Known Member

    A note on fix a flat.

    A service station owner in Texas settled for just under 1 million dollars with one of the manufacturers who used volatile propellants in their fix a flat.

    He was plugging a tire and when he pushed the rasp through the nail hole, a spark ignited the mixture of air and fix a flat that was just about the perfect mixture.

    The resulting explosion was estimated to be about the same as two sticks of dynamite. It did 40k damage to the station and the owner's skull injury almost killed him. After repeated surgeries his skull still was caved in almost an inch on the left side, a really nasty sight to look at.

    Most of the fix a flat today is non flammable, and it may also be a good reason to actually have nitrogen in your tires is you ever intend to use a similar product.


Share This Page