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About a week ago, I had new tires put on my car. The next day, I took a long trip from Birmingham, Alabama to New Orleans, Louisiana. I made it to the Mississippi state line around the time my TPMS indicated that I had low tire pressure. After stopping and checking the tires, I pinpointed the tire that leaked but couldn't find a nail or anything in it. So I filled it back up to around 34 PSI and hit the road again. About 20 miles later, the pressure had dropped to about 25 again and did so every 20-30 miles after that. It was pretty late and all of the mechanic shops were closed, so I went ahead and used fix-a-flat and that took me to New Orleans.

Upon arriving, I went ahead and had the tire replaced (the mechanic wouldn't repair a tire with fix-a-flat) but on my return journey home, about 50 or so miles outside of New Orleans, the TPMS went off again and did so intermittently until I got to Hattiesburg, MS. There I stopped at a mechanic and they tightened my valve stem. I went about 20-30 more miles when the TPMS went off again and said screw it, filling up the tire every 20-30 miles.

The strange thing is, I stopped at an auto parts place and tightened the valve stem more myself, then I rode at about 60mph and didn't have any more problems until I started driving about 70 again after about 70 miles. I took the car back to the mechanic that first changed my tire before I left Birmingham, he dunked the wheel in water and couldn't find a leak and made the asinine suggestion that a kid was probably pranking me.

The thing is: I know the leak is there. I know it leaks faster when I driving at higher speeds, and I was wondering if anyone had any suggestions as to what the problem might be.

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4 Answers 4

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I think the problem is not the tire. It is the tire valve. Did you changed them too? If you drive much faster, the tire valve deform because of centrifugal force and open this little leak. The valve could be just damaged by mounting the tire.

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The tire valve was replaced the first time with the TPMS system. I'll replace it again because I'm leaning toward the issue being a bad tire valve. Afterwards I'll give it a run around the Interstate that surrounds my town and come back with results. –  Uncle Taco Jul 15 at 17:37
    
After replacing the valve I've had no more problems. –  Uncle Taco Sep 13 at 18:12

The problem you describe with new tyres on alloy wheels can happen if the lacquer (shiny finish) on the wheel has become oxidised over time. When fitting the tyre, the bead seating on the rim should be pristine. If there is any oxidisation, bubbling or bumps, on the wheels bead seating it must be removed. With a rotary wire brush the bead seating should be cleaned off. The clean bead seat must then be painted with bead sealant and allowed to dry. This restores the airtight seal. The TPMS sensors very rarely give a problem, but they do have seals that can be replaced without the expense of a new sensor. Finally, the TPMS sensor valve cores are a differant core to a standard valve core, they are removed to deflate the tyre. Make sure the correct core has been replaced in the sensor, they look very similar to a standard core unless you know they are differant. Modern vehicles tend to have larger wider wheels and require a tyre fitting machine that is suitable for fitting larger wider tyres to avoid damage to the tyre when fitting them.

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I suspect the problem is not with the tyre, but the wheel - are they alloy wheels?

What often happens is that the edge of the rim corrodes slightly, which stops the tyre from sealing properly against it, allowing air to seep through between them. It's also not unheard of for alloy wheels to become slightly porous, allowing air to actually seep through the wheel itself...

When they fitted the tyres, did they use a sealing compound? and did they clean up the edge of the rim? Try that, and see if it helps it seal better. You should always fit a new valve when changing a tyre, so get that changed if they didn't...

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It is usual problem: contact place of tyre-rim is corroded. Just remove it

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