Repaired tire losing a little air

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Jun 3, 2005
Austin, TX
A week ago in my tire check I found a tire to be reading 26 PSI while others were on the dot 35 PSI. It was a no brainer, I inflated it back and took it back to the shop where I got them, they found a nail in it and repaired it.

The next morning I set them to 35 PSI, when my garage was at 45 degrees.

Today I checked them again, the garage was at 72 degrees. All tires read 36.5 PSI, except for the repaired one, which was at 35.1 PSI.

Seems it had leaked a little. I think the repair wasn't done right. I am going to keep an eye on it for a while with my weekly pressure check and see how this pans out. I have never had a repaired tire lose more air than one that was never injured.
It could just be a bad repair job. I'd also check the valve stem to make sure it's screwed in all the way; that can cause a small leak.
Yes - you may have a problem. And you're correct with keeping tabs on the pressures until you've noticed a definite trend.

If there is a slow leak, it may pay to find it yourself. My experience with shops is that they are sometimes lazy about finding leaks. A tire with a leak as slow as you have may need to be overpressurized so the leak presents itself. Once you find it, discussion with the tire place should be easy.
Checked this morning, after taking a 200 mi trip yesterday, all readings were exactly the same.

Is it possible that the patch needs a little time to seat?

In any case I will keep checking it.
There could also be a small leak around the bead. I have this problem with tires mounted on aftermarket rims at Walmart. They didn't use the correct weights, so I always had very slow bead leaks. Lesson learned: never go to Walmart for aftermarket tire work.
When you set them to 35 psi, Did the repaired tire need more air than the other tires? When you use a compressor the air is heated. Depending on the type of commpressor and the amount of air added, you can often see a "drop" in pressure after that air is allowed to cool in the tire.
It's possible that the tire needed a little time to grow. Once it did, the pressure stabilized.

Don't forget, you're really overkilling the pressure by measuring to the nearest 0.1 psi. Even sunlight will cause measureable differences at this precision level.
Here is how I set tire pressures; I know it is anal. I set them with a compressor to more or less 40 PSI the night before, let them cool overnight, then in the morning, when the garage is cold, I bleed them down to 35 PSI with my dial gauge. This led me to believe that the change in temp is most likely not the root cause.

I will keep an eye on it and see how it pans out.
I like Jonny's method. I use multiple "puffs" of the gauge to bring 'em down.
Checked today, 2 weeks from discovering the leak. No pressure loss at the repaired tire. I guess I am home free.
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