Redd

Maybe 6 weeks ago I topped up all four tires, from about 26 back up to 32. My bad, I don't check them very often. So last week I was surprised when the TPMS went off, and one tire was at 22 instead of 31.5. Tire shop said...no screws, no holes, it was leaking from the rim and they just resealed that.

But I know I didn't curb that tire, didn't hit any debris with that tire, kinda baffling that just "all of a sudden" one wheel rim would start leaking that badly??

Evil elves stealing air at night? Acid rain making the wheels porous? Something else that I'm missing, in my foolish expectation of a logical reason for that?

ex-quattro PETE

Corrosion?

MurrayA4

Redd I would suggest changing out the tire valve, These things are not always perfect.Cheap fix if it works.

Bob Petruska

Agree, the alloy wheel gets scratched when mounting a tire, that scratch starts the corrosion (doesn't take much for a leak) at the tire bead mounting area. Living in road salt country adds to the problem.

My sister had all 4 tires doing that, we needed to top them off every 2 days. Unmounted the tires, applied sealer at the beads, still leaked, did it again, still leaked! I said that is enough, had the tire shop remove all 4 tires from the rims, I then personally bead blasted the inner rim area that the tire covers, also sanded those areas with 220 grit, applied self-etching primer, then painted with hi-temp metallic sliver. Never a leaky tire since doing that.

shokhead

Hey, I put 1000 miles on the rear tire on my bike. All I did was the same thing I've done for the other 22k I've put on many tires, put 110psi in on Sun. Well one Mon night and out of the blue, the rear tire blows off the rim, loud as hell. Took it to the bike shop just to be safe and they had no clue why but everything checked out fine and no problems since.

Redd

Murray, I'd agree with you and should have been there to watch the guy looking for the leak, he said rim not valve though. And those metal caps should, in theory, stop a leaking schraeder valve anyway.

Corrosion? Yes, the car is kept fairly clean and dry, that's why I mentioned maybe the wheels have gone porous from acid rain.(G) This is the first time since the car left the factory that anything has been remounted, or developed such a fast leak. i.e. 10# in 6-8 weeks?! WTF. And no, today wasn't colder, it was actually warmer than the day I had last topped them up. No visible corrosion on them, in any case.

Bob, I can see doing all that refinishing with junkyard wheels (I had some issues that way once) but with the factory set, after four gentle years...Don't you go make me question the quality of my Audi now.

Or maybe I can get four plain black steel "police and taxi" wheels for the car? You know, like an old Plymouth police car set? They were just too dumb to leak. Or maybe, too well bred? Would old Beetle wheels fit? (VBG)

Bob Petruska

My sister's problem developed after the worn OEM tires were removed and the next set put on in October, the leakage started in April/May after exposed to winter salt. My past Audi and VW new alloy rims always needed to have the wheel bead area lightly sanded as you can see some corrosion after winter salt. If I was replacing my tires on my 2014 Q5 at my friend's shop, I would definitely lightly sand the bead area of the rim and make sure I use good rubber bead sealant.

On refinishing my sister's rims, I did not refinish the outside exposed areas of the rims, only the part (bead to bead) that the tire covers.
You stated in your post that sealing the tire to rim fixed your problem. So you should be fine. Remember that removing/reinstalling the same tire usually chews up the tire bead somewhat and introduces even more sealing problems.

jimdolian

If I were faced with this situation, I would take the car to a reputable tire business and do the following: (1) ask them to remove each wheel in turn and submerge the wheel in water until the leak was clearly identified; (2) mark the rim and the tire with the exact leak location; (3) dismount the tire from the rim and carefully examine both at that location; (4) repair any anomalies on the rim if that is required; (5) remount the tire on the rim at a different location and repeat steps (1) and (2) above; (6) if the leak is gone, problem solved; and (7) if the leak re-appears at the previously marked rim location, consider further remedial work on the rim or (8) if it appears at the previously marked tire location, replace the tire. Just my thoughts, FWIW.

Redd

Yeah, JM, I was just hoping to avoid the time and expense of pulling all four and futzing around, but it may come to that.
I got back in the car tonight, and fool that I was, I had thought that the TPMS had gone off because of the 21# tire that I found on my second try, so I had stopped there. We know what happens when you make assumptions....ONE LOW TIRE didn't seem like such an unreasonable assumption.

No, tonight the car tells me, only now, that the RIGHT REAR tire is low now. LF was the one remounted. Why on earth is the car so snarky that it tells me RIGHT REAR now, but before it could only tell me THERE'S A LOW TIRE somewhere or other?

I had this on the last car, when the tires were much older and they were on secondhand wheels. All four were remounted and sealed after a thorough cleaning and air mysteries went away. Foolish me, I though a much newer higher end model wouldn't come with the same issues. At least, not so soon!

Unreasonable assumption, huh?

apoelistas

Last time I had something similar, was an old puncture. The guy who did the repair had over rubbed (with the rotary tool) the internal rubber near the puncture, with the result of every 7 days to need additional couple of decimal (of bars) pressure, but it was not noticeable when they were searching for leaks. The foam polyurethane did not work so eventually I replaced all 4 tyres.

My wife had problem with 2 stem valves not properly tightened.

p.s. I never heard that aluminium rims can leak, unless there is a crack or a manufacturing irregularity / defective. I would get a second inspection done at a different place. In case the rim has cracked I would replace it.