I had noticed after getting the car coded and having access to real time pressures from the tpms, that the right rear tire was always a few pounds off from the others. The first time I noticed I blamed the dealer. Second time I raised an eyebrow. Third time I finally accepted that I had a leak. It was very slow, maybe half a psi a day, and would usually be week and a half before I'd lose enough pressure to trigger the tpms warning. As slow as it was my money was on a pinched/damaged tpms o-ring.
So, off to Discount Tire I go;
Pulled the assembly off, inspected it, no nails, no damage. So we dunk it;
No leaks. So, we blow it up to max pressure (50psi), dunk it again.
No leaks. Now I'm starting to think that this may be something that's load specific, and with no car weight, we're not seeing the issue. I ask him to break the bead, rotate it about the wheel and dunk it again (and to change the tpms seals while we're in there). Finally, the culprit.
Found 2 tiny leaks at the bead/wheel interface (marked in yellow). I have seen chrome wheels rust and leak from the bead in the past, but never aluminum wheels, so I was scratching my head. I did notice an area on the barrel with a heat affected zone when the tire was off, so maybe a previous repair had somehow warped the lip slightly? Regardless, we broke the assembly down again and used bead sealant to band-aid the issue. Seated the tire and dunked it for the 3rd time, leaks were gone.
All buttoned up, right as rain. Will keep an eye on it over the next week or two.
