Join Early Retirement Today
Reply
 
Thread Tools Search this Thread Display Modes
A Tire Pressure Mystery
Old 05-22-2013, 04:49 PM   #1
Thinks s/he gets paid by the post
 
Join Date: Jan 2006
Posts: 2,925
A Tire Pressure Mystery

Had a flat tire so took car to Costco to have flat repaired and tires rotated at same time. Marked tires so I could confirm rotation. The next AM before driving the car, I measured the pressure on all tires. I normally run them a few psi above mfg spec so I don't have to refill so often. The spec psi was printed on the Costco order form for the tech to follow if he desired. Apparently he did since the psi on 3 tires was exactly spec and lower than I normally set them.

The mystery part is that one tire , the repaired flat, was 26psi.........3psi low.
Concerned that I had a leaker, I went to Costco and refilled all tires w/ their nice automated setup to my normal pressure (also confirmed w/ gauge). Of course, the tires were slightly warm after driving a few miles but the important thing is that they were all refilled to the same pressure. The next AM, I measured all 4 again and they were all the same. 4 days later, I measured them again and they were within 0.5psi of each other.......so I conclude that the flat was repaired and holding ok (at least over this term).

Question: what happened to produce the 3 psi lower pressure after the flat repair? Since the tires were reset to spec, it seems clear the tech knew what the target was. I would have guessed all 4 tires were filled/reset at the same time so they should have been the same. I would guess my gauge is repeatible within +/- 0.5psi so a measurement should be within
1psi or so, certainly less than the 3psi difference seen.

Any theories?
__________________

__________________
kaneohe is offline   Reply With Quote
Join the #1 Early Retirement and Financial Independence Forum Today - It's Totally Free!

Are you planning to be financially independent as early as possible so you can live life on your own terms? Discuss successful investing strategies, asset allocation models, tax strategies and other related topics in our online forum community. Our members range from young folks just starting their journey to financial independence, military retirees and even multimillionaires. No matter where you fit in you'll find that Early-Retirement.org is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with our members, see fewer ads, upload photographs, create a retirement blog, send private messages and so much, much more!

Old 05-22-2013, 05:05 PM   #2
Give me a museum and I'll fill it. (Picasso)
Give me a forum ...
pb4uski's Avatar
 
Join Date: Nov 2010
Location: Vermont & Sarasota, FL
Posts: 16,407
Maybe you did have a leaker but the repair settled in and sealed up when you drove from home to Costco the morning after the repair or from Costco home after refilling.

Or the tech messed up when refilling the leaker the day before.

Or its you.
__________________

__________________
If something cannot endure laughter.... it cannot endure.
Patience is the art of concealing your impatience.
Slow and steady wins the race.
pb4uski is offline   Reply With Quote
Old 05-22-2013, 05:44 PM   #3
Thinks s/he gets paid by the post
 
Join Date: Jan 2006
Posts: 2,925
DW says I says it is never me who messes up (don't know how to put grins on anymore....something's changed).

So what does "repair settles in and sealed" mean? Any cause for concern that it may fail again, perhaps catastrophically, in the long term? Costco suggested that they would look at it if I brought it in but I wasn't thinking of this scenario.........
__________________
kaneohe is offline   Reply With Quote
Old 05-22-2013, 05:55 PM   #4
Moderator
MichaelB's Avatar
 
Join Date: Jan 2008
Location: Rocky Inlets
Posts: 24,412
Could be the flat has less air pressure to begin with. Was it a cool night?
__________________
MichaelB is offline   Reply With Quote
Old 05-22-2013, 05:57 PM   #5
Full time employment: Posting here.
 
Join Date: Mar 2012
Location: seattle
Posts: 643
Why not mount the spare and put the other on probation for a week?

Tires with slow leaks, if that's what is going on, go soft slowly, not quickly.
__________________
bld999 is offline   Reply With Quote
Old 05-22-2013, 06:59 PM   #6
Thinks s/he gets paid by the post
JPatrick's Avatar
 
Join Date: Jun 2005
Posts: 2,494
If you have gone 4 days with no problem, just continue to check every couple of days. The initial issue was likely a tech screwup. Nothing to see here.
__________________
JPatrick is offline   Reply With Quote
Old 05-22-2013, 07:20 PM   #7
Thinks s/he gets paid by the post
 
Join Date: Jan 2006
Posts: 2,925
Quote:
Originally Posted by MichaelB View Post
Could be the flat has less air pressure to begin with. Was it a cool night?
Not real cool........recorded the temp in AM when measured but too lazy to look it up......probably around 60F. I'm thinking the temp effect would be minimal and would go the other way.......the other 3 tires were slightly warm.....maybe 2psi increase from the short drive. They probably would have cooled significantly by the 1-2 hr wait but, if anything, would be hotter than ambient.
I assume the tech just drained some gas out of those tires to adjust to spec so, if anything, they were slightly warmer than the repaired flat. I assume the repaired flat would have the ambient temp when filled so would decrease less in pressure with a decrease in temp.

If the gas used to inflate the flat were significantly warmer than ambient, that might explain it?
__________________
kaneohe is offline   Reply With Quote
Old 05-22-2013, 07:30 PM   #8
Thinks s/he gets paid by the post
BUM's Avatar
 
Join Date: Feb 2004
Location: Mid Hudson Valley
Posts: 1,778
Best advice - Change the air on all four and remeasure every other day.
__________________
In a panamax down by the river.
BUM is offline   Reply With Quote
Old 05-23-2013, 06:52 AM   #9
Thinks s/he gets paid by the post
BUM's Avatar
 
Join Date: Feb 2004
Location: Mid Hudson Valley
Posts: 1,778
Pressure gauge not accurate? Use more than one - then take an average.
__________________
In a panamax down by the river.
BUM is offline   Reply With Quote
Old 05-23-2013, 07:51 AM   #10
Thinks s/he gets paid by the post
 
Join Date: Oct 2008
Location: Naples
Posts: 2,161
Put some soapy water in a spray bottle and shoot it around the rim of all the tires AND the stems to see if you can see any bubbles forming. I've seen a lot of leaks around the stems.
__________________
JOHNNIE36 is offline   Reply With Quote
Old 05-23-2013, 08:11 AM   #11
Thinks s/he gets paid by the post
imoldernu's Avatar
 
Join Date: Jul 2012
Location: Peru
Posts: 4,616
Possibilities:

"Settling in" - especially on aluminum wheels, where the bead doesn't make a perfect seal, when the tire is first inflated, but subsequent driving completes the seal.

Valve leak, that happens when the little valve seal didn't seat properly. Often this corrects itself with a bump, or the next time the tire is inflated. If this is suspected, just tapping the pin usually reseats the valve. Can check with a drop of soapy water.

Tiny leaks, as with tacks or bits of wire often self-seal.

During re-inflation after loss of air, temporarily over inflate by 10 pounds then let air out to desired pressure.

My preferred solution is to use pressure can of flat-fix. The mechanics go crazy when you do this, as it's a bit messy when putting on a replacement tire, but three or four dollars does the trick to save an $80 tire that still has tread remaining... and if the "industry" doesn't like the solution, IMO, they shouldn't sell the product.

MY older cars often begin with "slow" leaks that I fix with a shot of flat fix. Hasn't failed me yet.
__________________
Today is the oldest you've ever been, and the youngest you'll ever be again. - Eleanor Roosevelt
imoldernu is offline   Reply With Quote
Old 05-23-2013, 08:13 AM   #12
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
REWahoo's Avatar
 
Join Date: Jun 2002
Location: Texas Hill Country
Posts: 42,074
Valve stem fart...
__________________

__________________
Numbers is hard

When I hit 70, it hit back

Retired in 2005 at age 58, no pension
REWahoo is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


 

 
All times are GMT -6. The time now is 04:32 AM.
 
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.