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I only drive during the weekends, so most of the time my car is always in the garage. I have not been able to buy myself an air compressor, so what I do is I always have my tires check at my local gas station, which is about a kilometer away from my house. Now I have experienced problems with my tires, even if they are just about a couple of months old, I seem to think this is because of the low tire pressure I always have when I have them checked.

So I am thinking if my short drive to the gas station affects my tire. I drive at around 20 - 40kph on average when going there. There are a couple of potholes along the way, but I don't drive over them at speed. Does the tire having problems with its beads related to the low tire pressure I get and I drive it to the gas station for about a km? My tire pressure is always 35psi, but I always get to see my car run on 28-30psi every start of the weekend.

I am really wondering why this is happening, the problems only arise when the car is left for a very long time(sometimes I only get to drive it around 1 a week, at dawn for about 3km then not use the car again for about a week).

  • Am I understanding you correctly? Your tires are only a couple of months old, you fill them to 35 psi every week, and by the end of the week they are down to 28-30 psi? That's definitely not normal. I think something must be wrong with the tires or the way they were installed. – Nate Eldredge Nov 7 '14 at 12:12
  • Yup, I had them back to the dealer I bought them, they replaced the tire valve but we will still have to observe, they checked the tires for problems but their main guess is probably the valve. But they also told me to have my suspension checked, which I will next weekend since my suspension might also be causing some of the loss of pressure. – marchemike Nov 10 '14 at 2:38
  • I don't see how the suspension could be at fault if you are losing pressure when the car is not even being driven. I'm starting to become suspicious of what this dealer is telling you. By the way, is the pressure loss in all four tires, or just one? – Nate Eldredge Nov 10 '14 at 3:25
  • @NateEldredge it depends, on some weekends it's all four tires, but on some weekends just one. I park my car in a covered garage which is on cement and water and other stuff doesn't reach it. – marchemike Nov 11 '14 at 0:00
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First of all, the short amount of driving you do prior to getting them refilled is not going to cause the tire itself any problems. The biggest problem you'll see with tires which are run low is the amount of heat build-up in the rubber. Not only is the low pressure not really that low, the distance you drive is not enough to cause you worry.

Secondly, I'd suggest you have a slow leak (obviously). There are only two places where you can have a slow leak, discounting an outright hole in the tire.

  • The first place is the valve stem. If these were not replaced the last time tires were installed (except for Tire Pressure Monitoring Systems - TPMS), the shop did you a disservice. New ones should be placed each time to ensure there aren't any problems for the life of the tire. These could possibly leak through the valve core (schraeder portion) or where they seal to the rim. TPMS valve stems could possible have issues, but are usually more robust than regular normal ones. These are much more expensive to replace.

  • The second place is where the tire seats on the rim. If this area was not cleaned correctly, has corrosion, a leak could form there. If lube/sealant (many tire shops here in the states use soapy water) was not used during the installation process, this could also lead to a leak.

As for the leak itself, I'd suggest your tires are leaking at the rim. Something a lot of people don't realize is that the act of driving helps to keep the tires sealed on the rim. When the tire is ran down the road, there is a certain amount of heat build-up (as I already suggested) in the tires. This softens the rubber just a little bit and allows it to become more fluid (for a lack of a better word). This fluidity means that the tire is pliable and will move where needed to flow around the rim and remain round. Mind you, this isn't big amount. Just enough to help keep the tire sealed on the rim. When a vehicle sits for a longer period of time, the tire starts to incur a flat spot. This flat spot also transfers to where the rim meets the bead of the tire. Very small gaps can occur at these spots, which can cause the small air leak. Again, these are not large gaps, be enough for air to escape. Another thing to think about is that as a tire has less and less air pressure in it, it has a propensity to leak faster. So, your tires may leak down 5psi each week (if left alone for a long length of time) until it gets to say 15psi, then drop down to nothing by the next week. (This is an exaggeration to make the point). Just by keeping the pressure up in the tires, you'll shouldn't run into this problem.

Bottom line here is, you can do two things:

  • First, drive the car more. In my opinion, this is where the main problem lies. This also helps against dry rot cracks forming.
  • Second, you can possibly take it to a tire shop and have the tires reseated (break the bead, throw some soapy water sealant around the rim, and reseal the tires). This would probably incur the cost of the reseat, plus the added bonus of having to have them rebalanced.
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    @RoryAlsop ... I squeak one out every once in a while. – Pᴀᴜʟsᴛᴇʀ2 Nov 7 '14 at 13:30
  • Is the gauge used to check the pressure at home truly accurate? In passing modern tyres destroy themselves from the inside to the outside, so any running on low pressure may cause serious internal damage. – Allan Osborne Nov 9 '14 at 12:23
  • @AllanOsborne ... accurate enough. No gauge is going to be perfect, though the air pressure will never be the perfect pressure. Tire pressure should be checked when cold, as you know, therfore it makes sense to check it at home. The air pressure changes when the tire heats up (gains pressure above nominal) and then goes back to regular when the tire cools. – Pᴀᴜʟsᴛᴇʀ2 Nov 9 '14 at 15:31
  • All tyre pressure gauges in UK garages must be independently adjusted and calibrated with a certificate issued, no less then every three years. Most petrol stations do not do tyre pressure gauges for drivers too use because of this, comes under the heading of Public Liability. – Allan Osborne Nov 12 '14 at 19:16
  • @AllanOsborne ... I guess I'm glad I don't live in the UK. Thanks for the explanation. – Pᴀᴜʟsᴛᴇʀ2 Nov 12 '14 at 19:36
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This topic is pretty covered, but instead of using normal air, ask your tyre dealer to put nitrogen in your tyres. The compounds are a lot thickers and don't leak out as much as air does. My weekly air pressure checks are now every 3 months which it will only go down by 3 PSI.

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