I just got a set of used 18" ADR Sokudos about 4 weeks ago. Got 4 Nankang NS-II's mounted and balanced and the next morning one of them was flat. Took it back to the place that mounted them and they remounted the tire. That lasted about 2 weeks, but I kept noticing a vibration when on the highway, felt like an out of balance wheel. Took it back to them again, they rebalanced it, and put it on the car. Drove home, vibration was gone. Next morning got up, did a grounding mod to the car to try to get rid of some of te hesitation with my 04 WRX, took it for a little drive, then back home and parked it. A few hours later went to go run some errands and the damn thing was flat again. When I say flat I mean flat, absolutely no air in the tire, no just low. Any ideas? I am going to get it remounted and balanced in about an hour, hopefully everything will be fine.
Side note, the first time they were mounted we found a small burr on the inside of the wheel where the tire seals against the wheel. We put some sealant on there and it didn't leak until the next morning. After it went flat and I took it back to them, we checked to see if the burr was causing the problem and it was gone. That's what I originally thought was causing the problem. Now I am clueless. Please help

 

Get a spray bottle and fill it with about 25% dish soap and 75% water and pump up your tire and spray the solution on it. You should see bubbles - mark the location with a grease pen and then show the dealer where they went wrong.

 

Use the soap solution to check the valve stem core (underneath the cap) as well as the base of the stem where it enters the rim.

--
0==WW==0
"…axles of evil…" - george w. bush

 

look for a nail.. it might be a tiny bastard

 

I figured it out I think. That little burr I was talking about was still there. When I took it back to my friend at the tire store we resurfaced the area of the wheel that contacts the tire and so far so good. I think what was happening is when I would park, I would randomly stop right on that area with the burr putting pressure on that area and causing it to leak. We tried the soap and water test at the tire store and there were no bubbles. That's why this seemed so confusing.

 

The tires are not the best for performance. It also took quite a lot of time to balance them correctly. We had to road force each tire and rim combo 2 or 3 times to get it right and it still is not perfect. Looking back on it I wish I would have waited and bought the KDW2's that I really wanted. They are not terrible, just not the highest quality. Then again, this could have nothing to do with the tires. It maybe a problem with the rims. If you are serious about buying them I would sell you mine for a discounted price. I just took the rims off my car for the winter and am going to get the other tires anyway. They have about 1000 miles on them and look brand new. I would sell them for 250 plus shipping. Let me know.

 

it could be the stems of the tire....

 

You probably have a broken belt. The same thing happened to my on a set og Kuhmo's about a year ago driving through DC. The tire would just loose air and I would have to fill it once per week.

 

They are fine now. It ended up being the burr on the lip of the wheel. The have not lost any air pressure since then.