Not sure if this makes sense, but I wonder if other users have had a similar experience.

When I first got my car, it had Pilot Sports all around (225/40/18 and 255/35/18) and I kept it at the OEM tire pressure (33F and 37R). Left rear tire would lose about 4 lbs of air a week, where the other three would lose about 0.5-1 (which I think is acceptable, and would stop losing over longer periods of time). No tears in the sidewall, no nails, etc, and I replaced the internal valve (but not the entire valve stem). Edge of the rim did have some minor hit damage, and I'm unsure if it's possible that the wheel itself was leaking air.

Since the rears wear about twice as fast as the fronts and they were soon bald, I got some Pirelli Pzero Nero's in the same size placed on the rears (but kept the original valve stems). Problem went away on that wheel. I figured it was probably the tire itself, or maybe that the tire got too bald and was leaking through or something.

Everything was now fine.

Now, on the Pilot Sports I have on the front, I'm getting the same exact PSI drop issue now on the left front. Other three tires are fine, and the fronts both have about 5-6/32's of tread left. No nails, sidewall issues, etc. Replaced the internal valve on that wheel and the still the same.

So the question is: Is it common for these Pilot Sports to start leaking air over time as they get older? Regardless of tread amount left? If anyone has had any similar experiences, please share.

If so, I'm debating whether to just ditch everything and start new with four fresh Pilot Sport A/S Plus's, but at the same time don't want this same problem to occur in the future under the same brand. If so, then I'm open to other UHP A/S tire recommendations....

 

I bet the inventory sticker was still attached to the bead. There is a little 1 inch or so wide sticker on the bead itself. If you dont remove it, it tends to cause air to gradually leak out (some faster than others).

 

I thinking valve stem issue

 

Well, I left the original valve stems (with my new replacement cores) in the rears when I swapped out the tires (don't ask why...) and it stopped leaking, so that kind of disagrees with the valve stem theory? idk...

 

the new cores may have been the answer ... in the end as long as the leaking has stopped it's a good thing

 

Had a somewhat similar problem. Do the "water" test. That should tell you if it's the rim itself or the tire. In my case it was the tire.

 

New core didn't help in that tire, 4psi loss in one week. I may have to do the water test.

 

Any update?

 

had a similar issue, at first it was the valve stem, after fixing that, found out the tire wasnt sealing around the bead, a little grinding and some black stuff on it and its now fixed.

 

Are the wheels chromed?

I have had 2 different sets of AMG wheels on 2 different cars that exhibited exactly the same thing and it turned out to be a slight bit of deterioration of the chrome over time on the inside rim where the tire bead goes. I had to have the tires dismounted, cleaned up the inside of the wheel and added bead sealer to correct the problem.

Just a thought