Weird tire pressure issue

[Hmmv4me]

I have a weird issue with my 12 bolt wheel. The tire is aired up and looks good, however, when I check the tire pressure, I get 0 pressure. If I try to add air, if goes from 0 to 40psi in less than a second and when I let the air back out it goes to 0 in the same amount of time. I removed the valve stem to to see if it was clogged, stuck a 2.5" nail in the stem and it hit something hard like rubber. Could the run flat be sitting wrong or something? Is it safe to split the wheel with pressure in the tire?

 

[Coug]

NO!!!!!

Do NOT split the rim with any pressure in the tire.



Very bad juju

 

[Coug]

I'm not present at the tire to see exactly what is going on, but definitely sounds like something blocking the stem. If there is no way to push the blockage out of the way, maybe tapping the nail with a hammer gently or something, I think that personally, and I'm not advocating this for anyone else without actually being present, I would use a small drill bit and try to make enough of a hole in the blockage to allow the air to leak out overnight or whatnot.

I can't think of any safe way to remove the tire while under any type of pressure.

 

[Hmmv4me]

Yea, I didn't think splitting the rim was smart, I'll try tapping the nail lightly a bit. If that don't work, I'll give the drill a shot.

Thanks Coug

 

[86humv]

Safety glasses.

 

[Bulldogger]

Yea, I didn't think splitting the rim was smart, I'll try tapping the nail lightly a bit. If that don't work, I'll give the drill a shot.

Thanks Coug

+1 for full Personal Protective Equipment while working on this. Note that the nail (or whatever) once you get the foreign object out of the way, will be exposed to that full tire pressure, and will become a bullet if you don't have something heavy very firmly clamped to that nail. I think I'd use a long thin rod instead, like some of that light steel used on cheap plastic signage on the side of the road by shopping centers, and I'd clamp it in some large vise grips.

Bulldogger

 

[DatGuyC]

What type of run flats are you using? The one piece rubber ones have notches in the rim where the valve stem should sit so its not blocked by the rim of the runflat.

 

[Hmmv4me]

I'm not sure, I haven't taken one apart yet, all I know at this point is is it is a 12 bolt rim on a 90 M998 with radials.

 

[98G]

+1 for full Personal Protective Equipment while working on this. Note that the nail (or whatever) once you get the foreign object out of the way, will be exposed to that full tire pressure, and will become a bullet

Bulldogger

Nah.... it is exposed to the pressure in direct proportion to the surface area involved. Nail head has maybe 1/25 of a square inch of surface area. At 50psi it is exposed to 2lbs of force. Dangerous to eyes? Absolutely. But in the scheme of things it doesn't compare to a decent pellet gun.

On the other hand, consider what would happen if you split a 2 piece rim while inflated to 50psi. Rough estimate of surface area gives us 3300 square inches at 50 pounds per inch. That yields 165,000lbs of force. A bomb by anyone's standards.

Edit to add another point of comparison. To launch a lowly .22 caliber bullet, roughly 20,000 psi is the operating pressure.

Anyway, I hope someone found the numbers entertaining.

 

[Hmmv4me]

Problem solved. Some genius installed the run flat backwards. I removed the valve stem and left the tire on the truck for a couple weeks. Most of the air leaked out. I placed the rim under the jack of my trailer and loosened the nuts 1 turn at a time going around the wheel until i heard a psssss. The remaining air leaked out. The notched side of the run flat was on the wrong side... easy fix. Just flipped the rim, retorqued and inflated.
.

 

[waayfast]

Whew!!! Glad it turned out ok--- as I read thru the text here, the ALARM BELLS were screaming----- ------ ---

 

[Hmmv4me]

Whew!!! Glad it turned out ok--- as I read thru the text here, the ALARM BELLS were screaming----- ------ ---

Yea, I was sweating a bit, but got it done. Hate to toss the tire...

 

[Coug]

Thanks for letting us know, always nice to have some closure on an issue just in case someone else has the same issue.