WAY OT..car tire losing pressure

[oldpotatoe]

So....2000 Beetle, one tire loses about 10 psi per week. Have had the tire(Pirelli, not worn out) checked twice with nothing found. So..rim issue? Any idea how to check that?

I'm thinking of putting in some sealant to see if it spoozes out somewhere..don't want to replace the tire only to have it be the rim. No obvious wacks to the rim.

This in the running for most OT post. :eek:

[weisan]

Since when did you go tubeless?

[Tickdoc]

So....2000 Beetle, one tire loses about 10 psi per week. Have had the tire(Pirelli, not worn out) checked twice with nothing found. So..rim issue? Any idea how to check that?

I'm thinking of putting in some sealant to see if it spoozes out somewhere..don't want to replace the tire only to have it be the rim. No obvious wacks to the rim.

This in the running for most OT post. :eek:

valve stem or nail/screw most probably.

[oldpotatoe]

valve stem or nail/screw most probably.

Changed valve and checked twice by tire guy(tire removed from rim and inspected)..found nothing(?)..maybe just missed it?

[Tickdoc]

Changed valve and checked twice by tire guy..found nothing(?)..maybe just missed it?

well that is a head scratcher. Sealant may make sense here. My son has a slow leak on one of his tires just like this, but the rim was slightly bent and straightened, so I attributed it to that.

You gonna put orange seal in there ;~)

[William]

except there is a Brady joke in there somewhere... :D






William

[William]

We had a similar issue with our Volvo. Checked the tire, valve stem, and rim numerous times and never could figure out what was causing it. :confused:







William

[93legendti]

My left back tire has the same problem

[AngryScientist]

could be the seal at the rim/tire bead interface. could also be the seal at the valve stem/wheel interface.

get a spray bottle and make a soapy water mixture. lay the wheel down on a flat surface and spray the soapy water mix along the diameter of the wheel/tire bead and watch very carefully for bubbles to form. do this on both sides of the wheel and at the valve. if it's leaking, bubbles will form.

have the tire inflated to just over the max allowed PSI to speed up the process.

[Tickdoc]

My left back tire has the American problem

what, it gains pressure?

[Mikej]

Aluminum rim? If so, at that age I would suspect corrosion at the bead seal surface. Happened on my 02 Accord. I had to have the tires removed and they wire wheeled the surface smooth.

[93legendti]

what, it gains pressure?
Damn auto correct!
I meant to type "same"!

[oldpotatoe]

Aluminum rim? If so, at that age I would suspect corrosion at the bead seal surface. Happened on my 02 Accord. I had to have the tires removed and they wire wheeled the surface smooth.

Assuming aluminum or magnesium..that sounds like a real possibility. Hopefully some tire sealant..pressure..drive.and look to see if it ooozes out. Surprised it's so common.

[Brian Cdn]

Aluminum rim? If so, at that age I would suspect corrosion at the bead seal surface. Happened on my 02 Accord. I had to have the tires removed and they wire wheeled the surface smooth.


Same...

Had this issue. Tire guy cleaned up the rough edges and corrosion on rim with wire brush. Leak stopped.

[TBLS]

Had similar problem....have tire removed and have them clean/scrape rim...and inspect...took 3x to discover a small dent in the rim...also closely inspect from the inside for any damage.

Assume a new phenomenon on an old tire. If a new tire defective?

[Tony T]

Had the same problem and it was the rim. I thought I was going to need a new rim, but the tire shop was able to coat the rim with something that fixed it. (not sure what they used)

[christian]

Slight rim bend or corrosion at the tire/rim seal. Sealant will do the trick. I have the same issue with my Hakka 2s on my Mercury. The summer tires seal fine, but the stiffer sidewall on the Hakka 2s seem to exacerbate the problem and I lose 10 psi over ~2 weeks. Sealant fixed it.

[bpiecuch]

As most have said, there are only so many places you can have a leak.
- Tire itself
- Tire/Rim interface
- Valve Stem

AngryScientist's method of checking is great. You can probably do the soap method while the tire is still on the car as well. Though, it won't be as effective as letting the soap sit there.

With some TPMS systems, there is an extra seal at the valve, which needs to be replaced once in a blue moon (or when the valve is disassembled.) But, I don't believe your 2000 Beetle has TPMS.

I would guess that there is small leak at the Tire/Rim interface. Older alloy rims can corrode, or the plating might crack off. Both will lead to slow leaks. Steel wheels can rust/corrode as well. Some idiot dealer put clamp-on weights on my wife's alloy rims (which is a no-no.) 1 year later, they're all corroded and one has a leak...

Best solution is to take it to a tire guy and have him remove the tire and check the rim. You'll need to pay for the remount and balance, unfortunately. Might as well replace the valve (~$3) while you're at it. Good luck.

[Dirtdiggler]

Fluctuating temps will result that especially with aluminum rims. Careful to not add to much sealant, it will cause unbalance and might clog up the pressure sensor

[biker72]

Similar problem with my wife's 2005 Cadillac. Discount Tire checked out both the tire and rim. (Passenger rear tire) They could find no problem.

I eventually got a new set of tires for the car. Problem disappeared.

I'd go with some sealant if the tire has some miles left in it.

[Hank Scorpio]

Had the same gremlin on the outback. Finally found a small shard of glass that had weaseled itself into and then was engulfed by the tread almost imperceptible. Did a plug and patch because I had just replaced all four tires holding well for now. Probably get new tire inn the spring because I am turning that over to mom and girl and I inherit her broke ass Jetta.

[Matthew]

Probably what others have said about aluminum wheels. My 2003 Toyota had this issue as well.

[Tony T]

This in the running for most OT post. :eek:

Nope, sorry: http://forums.thepaceline.net/showthread.php?t=200289

:)

[ergott]

You should be on tubulars anyway.

[ultraman6970]

If the valve is not losing air, you have no punctures then you have rust between the tire and the rim... the tire can't sit well and then you have air coming out from the side of the rim slowly.

You have to take the wheel to get that fix, is easy the problem is that we are talking about car wheels. Remove the tire and then with a mechanical like sanding tip basically scrape all the white stuff that is around the the rim, just where the tire sits. Mount the tire again and good to go.

If you need new tires find a place that will do this for free, some tire places wont do this at all even if you pay them for it so you need to find the right place.

[cmbicycles]

You should be on tubulars anyway.

+1, don't be a Nancy ;) :beer:

[kitsnob]

Possible issues:

Valve stem damaged

Tire pressure monitor stem seal leaking, crushed, collapsed

Pin hole in tire only seen when weight is on tire - (spray windex/water from a spray bottle to find/reveal leak) and not just "dipped in water"

Cracked rim

Chrome rims? - Chrome is peeling on the lip/edge whre the tire bead seals against the rim - fix is to rechrome or scrape off the peeling chrome for a better seal

Good luck

(BTW.. I see all of this on a daily basis .. I'm in the automotive biz)

[DfCas]

Aluminum rim? If so, at that age I would suspect corrosion at the bead seal surface. Happened on my 02 Accord. I had to have the tires removed and they wire wheeled the surface smooth.

I second rim corrosion. My tire guy has a ball like abrasive tool he cleans up the bead area with, then a sealing/mounting gel he brushes on.

[Ralph]

could be the seal at the rim/tire bead interface. could also be the seal at the valve stem/wheel interface.

get a spray bottle and make a soapy water mixture. lay the wheel down on a flat surface and spray the soapy water mix along the diameter of the wheel/tire bead and watch very carefully for bubbles to form. do this on both sides of the wheel and at the valve. if it's leaking, bubbles will form.

have the tire inflated to just over the max allowed PSI to speed up the process.

This

[Fatty]

Our thrifty little station wagon with factory alloy rims has this same problem. Gets worse in cold, like single digit, weather. All four leak a little bit. And they bleed down at different rates. I fix my own tires, have for years and you can spray soapy water till the cows come home and there is no evidence of a leak. When it gets a little warmer I'll bust the tires off and clean up and paint the interior of the rim surface. I had this done years back on a different car, the tire tech used what looked like a heavy black paint.

[Ken Robb]

The aluminum wheel on my M3 developed a crack with no history or evidence of trauma. It was only about 1" long and on the inside. Wheel repair shop welded it and assured me recurrence was unlikely or they would not have fixed it. having said this I'll bet roughness at the bead is more likely causing the leak. Once you insert sealer will it affect the balance? I remember injecting some goo years ago that was distributed around the inside of the tire by centripetal force while I drove but the guy who replaced that tire later said it took a lot of extra work to clean out the goo/sealer. I would prefer a mechanical cleaning of the bead.

[Macadamia]

One more person saying, "same" here, but with a twist. Thought I found the source of a leak, seeing bubbles around the rim, but there was a tiny pinhole in a sidewall, that would leak for a week before the rim was able to start leaking.

For what it's worth I put a can of Slime in that tire and it was fine for 3 months until I decided to replace all my tires.

[ultraman6970]

What macadamia is a good advice... and if the up goes that way and swap the tires a few months after just be sure to see that the tire bed in the rim doesnt have galvanic corrosion and if it has tell the guy to clean that up mechanically (sand off) and leave the bead really clean or the new tire will leak as bad as the old one.

[rePhil]

If your tire guy is stumped and likes a challenge have him swap two tires / rims t see it it stays with the tire or rim.

I have heard stories of people putting bb's under their friends valve caps.

[11.4]

Is the rim chromed (polished look)? Chromed rims are notorious for corroding. The chroming is only done on the outer surface of the rim, and at the point where the chroming stops, it basically does so because it's weakly applied. This is just inside the outer lip of the rim. The weak application actually enhances corrosion in the area compared to bare or clear-anodized aluminum.

In rims that are the vintage of the car (if that's what's still on the car), the alloy was a lower grade compared to what's used on today's rims and more susceptible to corrosion. It could also be dented very easily by a tire installation. If the valve isn't bad, then I'd look to the rim bead. These are fixable, but if you have it happen once, you can anticipate that it'll happen again.

[hoonjr]

I had the same problem with my 2002 VW passat. I'm not sure I would recommend sealant but I would have them taken to a reputable tireshop and have them diagnose. I'd imagine if they find nothing structurally wrong with the tire/rim they will wirewheel the rim and then reinstall the tire with an extra liberal amount of bead sealer.

Damn, I'm glad to be done with VW. I know it could happen with any brand but the amount of CELs and love I had to put into my VW was maddening.

[carpediemracing]

Some related info.

Every 10 deg F drop in temp = 1 psi drop
Every month = ~1 psi drop

If you have a "chain store brand tire" (aka Goodyear for Goodyears, Firestone/Bridgestone for Firestone, not sure who else is associated with what brands) you can often get the store to do a warranty flat fix, i.e. they dismount the tire, inspect, wire wheel rim, bead seal (there's white as well as black versions), etc, all at no charge.

[45K10]

Make sure somebody didn't put a pebble inside the valve cap. My HS Physics teacher is still probably scratching his head on that one.

[rwsaunders]

Aluminum rim? If so, at that age I would suspect corrosion at the bead seal surface. Happened on my 02 Accord. I had to have the tires removed and they wire wheeled the surface smooth.

This...the rim surface oxidizes and seal is compromised. Also, try replacing the valve as I have had leaks as a result of an aging valve too.

[FL_MarkD]

All these answers and still not the obvious feedback; buy new wheels and tires. ;) Heck if someone has a tick they can't figure out someone tells them to buy a new bike :D

[Hank Scorpio]

Make sure somebody didn't put a pebble inside the valve cap. My HS Physics teacher is still probably scratching his head on that one.

BB's work too.

[NHAero]

My 2001 Ford Ranger had corrosion at welded joints within the rim rather than at the interface with the tire. Tire guy dunked the whole wheel snd showed it to me. Steel rims.

[Louis]

Avoid "Slime" type sealant unless you have no other choice.

I was talking to a tire guy a few weeks ago and he said that they hate it. It makes a huge mess inside the wheel that's a pain to clean up, and can cause pressure-sensing TPMS units to go bad.

[alancw3]

question, does the tire leak down to a certain pressure and then stop leaking or will it leak down all the way to flat? had a similar problem with my beetle convertible where tire would leak from 32 psi down to 20 psi or so and then not leak anymore. drove me crazy. tire guy finally found a broken off nail in the tire that was almost not noticeable. with todays steel belted radials a puncture will sometimes only leak down to like 20 psi or so and not go completely flat. had a staple in another car with same symptoms. i would check to see if leak stops at a lower pressure. if so my bet is on almost unnoticeable small puncture.

at the time i researched specifically pertaining to a vw beetle. if memory serves me correctly with the beetle alloy wheels an acceptable rate of loss of pressure is like 1-2 pounds per month. evidently the alloy wheels are more porous than steel and cause this loss. at least that was the theory.

[oldpotatoe]

Fluctuating temps will result that especially with aluminum rims. Careful to not add to much sealant, it will cause unbalance and might clog up the pressure sensor

Old car, no pressure thingy. Sealant, drove the car, looks OK this AM..so we'll see. No obvious sealant ooze. Thanks for and responses.

[oldpotatoe]

Some related info.

Every 10 deg F drop in temp = 1 psi drop
Every month = ~1 psi drop

If you have a "chain store brand tire" (aka Goodyear for Goodyears, Firestone/Bridgestone for Firestone, not sure who else is associated with what brands) you can often get the store to do a warranty flat fix, i.e. they dismount the tire, inspect, wire wheel rim, bead seal (there's white as well as black versions), etc, all at no charge.

Only been this one tire. The other 3 don't lose any air. Pirelli tires, about 3/4 done, wear wise. Hate to put tires on this thing as I drive it about 300 miles per year. Keeping it for the grand kid...11 years from now:eek:

[Ken Robb]

I just replaced the tires on my MINI. They still had plenty of tread but they were 6 years old and had lost a little grip due to hardening of the rubber. Then we got a bunch of rainy days in SoCal and I was very happy I had new sticky tires that work very well in the wet. As tires age and/or wear performance wanes so gradually that it's easy to miss the change. Then we are amazed how much better new tires feel. It's the same on bike tires too. :-)


FWIW Firestone Firehawk 500 tires. A new model that elsewhere in the world are sold as Bridgestone RE 760 II. The tires I replaced were RE 760 Bridgestones and I would have bought the II model because I was happy with the previous model. Tire Rack rates the Firestones as one of the best and they are a lot cheaper than tires with similar performance. I don't know why Bridgestone/Firestone made the name change for the USA.

[rwsaunders]

OP...as you are a tubular advocate, I'm surprised that you don't have a folded spare strapped under the Vdub bumper, ready to fill with a gallon of latex sealant (paint)...:cool: