The Toyo tyres I bought for my Mazda 6 lose about 2 psi in a week, that?s a loss of 6-8 psi if you check them monthly. I have never known tyres to lose pressure at this rate before and would like to know if this is the compound of the new tyres or is it poor sealing of the valves. Would using a metal valve cap help or is there any type of sealer that can be applied to the tyres on a regular basis that may slow up the loss of pressure through the tyre wall?
You typically lose one to two psi in the process of connecting the pressure gauge to the valve, so if you’re checking your tyres once a week the 2 psi loss you’re seeing could simply be due to that and not actually a loss of pressure at all. If you’re checking once per month and seeing a loss of 6-8 psi then that’s something to be concerned about. A loss of pressure can occur through a faulty valve, a poor seal between the tyre and the rim, and bleeding through the tyre carcass. Using a tyre cap is a good practice because it helps prevent dirt getting into the valve and causing it to leak. I wouldn’t be concerned about sealing the inside of the tyre; any loss through the sidewall is likely to be very small.