My darling wife's Jeep Grand Cherokee has a peculiar problem...the tires all keep losing what I consider more-than-normal air pressure. It has factory 17 inch alloys with Kumho KR21 touring tires with maybe 5000 miles on them. All of them will lose 7-10 PSI per month, the right rear has something else going on and will get down to 20 PSI within 7-10 days, guess I should have that one looked at.

Why am I losing so much air? I lose a smidge in my other cars, but not nearly this much. What should I look for with the leak in the right rear? There are no punctures, I think there's something funny with the bead.

What is a normal pressure loss, over, say a 30 day period?

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2002 Ford ZX2
2 x 2013 Honda Civics

Normal loss is around 1 psi per month. I've had tires that lost less than that. I think your tires are due for a dip in a tank of soapy water to see where they're leaking.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

Probably leaking from a corroded bead area. The tires will have to be dismounted and the white chalky corrosion removed. May even have to apply some glue especially made for this issue. Then you'll have to have them rebalanced.

You can check this yourself. Pull a wheel off, lay it flat on the ground, and pour some soapy water around the rim. Let it alls ettle down, and then look for small bubbles around the rim.

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Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport

Google: tire valve recall

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Palangi

2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg



TRUMP .......... WHITEHOUSE
HILLARY .........JAILHOUSE
BERNIE .......... NUTHOUSE
0BAMA .......... OUTHOUSE

corrosion around bead area is common on older chrome wheels.

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'O=00=O'
bmw 2002.
long live the legend

If the wheels are aluminum, occasionally you will have leaks through porous castings. All four wheels doing it seems unlikely though.

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

If this problem did not exist with the previous tires, I'd look at the Kumhos. Wonder if through a manufacturing defect, the bead is a touch too large in diameter. If this is the case, the tire should be walking around on the rim a bit.

Just to complicate things, the Jeep started out with a 16 inch wheel package, I bought these wheels off Craigslist with worn-out Michelins on them, drove them for a month or 2 before I put the Kumho's on there, so I really can't say if the wheels are the likely culprit, or the tires. I will say that the touring tires are not a good match on this vehicle: the sidewalls are too soft. I specifically went to 17s because the tall skinny Goodyear Wrangler ST's on the 16s were so mushy it wasn't even funny. I went from a 225.75r16 to a 235.65r17, so even with a relatively soft sidewall, the Kumho's are better than the Goodyears, but the firmer Michelins worked better.

I really had an issue with the Goodyears...I watched the tech try to inflate one of them on the wheel, and the sidewall was so soft and floppy that 2 techs had to hold it up to get enough air volume inside to make it inflate against the bead. If there is such a thing, they seemed flimsy. They were the factory fitment, but wore poorly and I got punctures in 3 of the 4 somehow. I replaced the factory GY's with one more set of identical tires before I gave up.

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2002 Ford ZX2
2 x 2013 Honda Civics

I got a letter from discount tire about faulty valve stems, as I haev been losing air also. If you got them mounted at Discount, take it back and they will replace free of charge.

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1984 300SD Orient Red/ Palomino
1989 560SEC
2016 Mazda 6 6 speed manual
1995 Ford F-150 reg cab 4.9 5speed manual

I got them mounted for free at the MB dealership where I used to work, palmed one of the older tech's a $20 to do it, so I don't have a whole lot of recourse on this one.

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2002 Ford ZX2
2 x 2013 Honda Civics

Ditto. I got the same letter last week...but for the vehicle that got tires two years ago! Nothing for the W124, which got a set a couple of months ago from same dealer. Go figure!

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

Maybe they're going through their database by invoice number. You'll get the notice for your other car in a week or two.

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Chad
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys

You might try a product called Green Slime. I used it on one of my tires with a persistent slow, slow leak and it worked fine. Never had a problem and did not mess up the balance.

I used that on my yard tractor. It worked great.

Just make sure you let the guy who changes your tires next time know so he can be prepared.

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Chad
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys

I think you should have them remounted and checked, all four.