All tires lose 1-2 PSI per month from permeation - that is normal. If you are topping up weekly, you have a real leak. The four common culprits are a corroded rim seal, a slow nail puncture, a leaky valve stem, and a bent wheel.
Aluminum wheels corrode where the tire bead seats against the rim. Most common cause of "no visible nail" slow leaks. Fix is to dismount, clean the bead seat, and remount with bead sealer.
A nail can plug itself partially and leak 1-3 PSI per day. Soapy water spray reveals it as bubbles. Plug or patch from inside is the proper repair.
Rubber valve stems dry-rot and crack at the base. Aluminum stems corrode at the core. Quick test: spit on the stem and watch for bubbles.
Pothole damage to alloy wheels causes hairline cracks invisible from the outside. Spray soapy water on the inside lip with the tire inflated.
TPMS sensors have a rubber grommet at the wheel. After 5-7 years it dries out and leaks. Often replaced as part of sensor service.
Small puncture from a sharp object that did not stick. Cannot be patched - replace the tire if confirmed.
| What You Notice | Likely Diagnostic Step |
|---|---|
| Same tire keeps losing air | Localized leak - inspect for nail, then bead |
| All four tires drop in winter | Normal temperature contraction - just top off |
| Tire flat in morning, fine after driving | Bead leak - heat re-seals it temporarily |
| Visible corrosion white powder on rim | Confirmed bead leak - dismount and clean |
| Hiss audible after pothole | Bent rim or sidewall damage - inspect immediately |
Tell us the tire, the wheel type, and how much PSI per day - we will tell you the most likely cause and what to ask the shop for.
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1-2 PSI per month is normal permeation through the rubber. More than 1 PSI per week is a leak that needs investigation.
Short term yes, if you keep it inflated to the door jamb spec. Long term it overheats and damages the tire. Repair within a week or two.
Most common cause is bead corrosion on aluminum wheels. The tire-to-rim seal breaks down where they meet. Other causes: cracked rim, valve stem, or TPMS sensor seal.
Only as a last resort to get home. It can clog TPMS sensors ($60+ each to replace) and ruins the inside of the tire so it cannot be patched. Tire shops hate it.
Patch from a nail: $25-$40. Bead reseal: $25-$60 per wheel. Valve stem: $5-$30. Bent rim repair: $100-$400.
Either it has a moderate puncture that leaks faster under heat, or it's a bead leak that opens up as the rubber warms and flexes. Soapy-water test both.