I realize that, as car guys, we give this advice out constantly to less enlightened friends and family members (along with "change yer oil!," of course.) However, doling out advice and actually practicing what we preach are of course two different matters entirely. A little knowledge can be a dangerous thing.

The root cause in this case is that it seems to be normal practice for a car guy to do a "walk around" on his vehicle every few days or so to ensure that everything seems in order. One of these flight checks is of course a visual on the tire pressure, which mostly involves looking for inconsistency in appearance or tell-tale sidewall bulges indicating reduced tire pressure. Unfortunately, application of an actual pressure gauge is usually reserved for:
1) "Long trips" in DD cars
2) Cars and Coffee runs in the Porsche

So this fairly cold (for SoCal) morning, I got a Tire Pressure Monitoring System idiot light in the '08 Jetta while talking the kids to preschool. "Drats!" I say. "How can that be?" I don't need idiot lights. I'm far too proactive and PM-oriented to be subjected to such pedestrian humiliation!" Since I'm under warranty, I immediately thought about the hassle of calling Downtown VW to get an appointment to have my TPMS checked out, since VW electricals are so dodgy, right? So after I dropped the kids off, I begrudgingly pulled into a gas station and used one of their awesome, filthy brass air chuck/pressure gauge delios to check the tire pressure. Three tires were fine, but one that "looked good" was at about 25 pounds instead of 34. Got in, started the car, noted that the TPMS light is out, smiled and snacked on some humble pie while congratulating myself on what a solid purchase my Jetta was!

 

I think I'd notice 9 pounds low. That is a lot!

 

Since I switched to nitrogen, I've gotten lax about that. Thing is the pressure never gets low any more.

 

I am way to **** about tires and tire pressure. My son in law came by and we checked his tires on his Audi A4. All four were down 9 pounds. UGH.... I a digital tire pressure gages in each of my cars. I check rental cars prior to leaving the lot. I even had the tires of a U-Haul trailer checked last week before I left their lot. I think I need help.......

 

Maybe it was 30. Perhaps someone can chime in on what the VAG spec is for the TPMS light to be thrown?

In fairness, at 6'3" my perspective for anything on the ground is extra bad

 

When I replaced my wheels, I was pondering if I should pit in an aftermarket TPS system. I thought I do not need some electronic device yelling at me to add air. I've had the wheels on now for over a year and they've held air beautifully. I have to admit, however, I have not check the tire pressure since installing them. Maybe I should have added the TPS system afterall. For what it's worth, always check them after winter storage.

 

One of the ways I can tell in my tires are down a couple (2) PSI is that I can see a drop in MPG's.

 

I'll argue the point that with us now running very low profile tires, it is difficult to "visually" spot a tire that is 4-5 psi lower than another tire on the car. There just isn't that much difference! So, I have become a little **** with the 993, as well and check pressures about twice a month. And, what I have found is that tire pressures drift down with time. At least on "some" of my tires. They drift so slowly that I don't believe I have a puncture but I am wondering if the seal at the wheel isn't perfect. Like, I'll see one tire drift down 2 psi over a two week period when compared to the other tires on the car. In my **** state, I have even gone around to all of my tires and made certain that the valve cores were fully screwed in, since I have found several times this not to be the case.

 

Great points. I have a box near the air compressor labeled "air tools," which includes an impact wrench, sockets and a valve core tool like the first one below, which I probably bought in the context of "bicycle repair." When I grow up, perhaps I'll invest in something like the Snap-On (second pic).

Continuing the tour, I also have a Black Jack tire repair kit in there. This kit has 20 vulcanized plugs, which allows you to make tire repairs with the tire still mounted on the car. While I wouldn't use this on a P-car, I've been about 90% successful on other cars. Same service your gas station used to charge $15 for.

 

Very true. Excellent point.

 

Nice post but it just depressed me to think about my mother down in FL. Last time I visited, her right rear tire on her Mercury Sable had 9 lbs in it. 9 pounds!! I nag her to death on the phone about changing her oil too but it probably hasn't been done either. At least her driving is mostly the typical 30 mph 'old lady' 5 mile trips to the grocery store. Probably in the left lane too.

 

+993

I have good eyes, and I can't for the life of me tell with 18" wheels when one is a little low, even up to 10 PSI low. You just gotta use the tire gauge.

 

And whenever I find a drop in tire pressures, I fully inspect every inch of the tire, on my hands and knees, looking for a nail/screw. Very happy when I find neither.

 

I had solid-rubber forklift tires installed last week. Took some stretching, but I'll never worry about stupid tire pressures again.


Andreas

 

Hi Ernie,

Good on you!! That's the absolute truth and true wisdom about 50-series and lower, tires. The gauge is the "gospel" about pressures and should be checked weekly, just in case that one may have picked up a nail or screw that will cause a slow leak.

I'm so OCD about this that I sent all 4 of my tire pressure gauges off to be calibrated at a testing lab to see which ones were most accurate in the pressure ranges I use. Needless to say, it was quite revealing so I usually use my digital Longacre one now.

Stay the course,