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After changing the oil today I went around with the pressure
gauge; everything still nicely north of 50. But I was mildly
horrified to notice that my valve stems appear to be cracking
around their bases. That makes me almost afraid to even put a
pump on them, because given past experience with bicycle valves
a crack like this can quickly grow and start leaking.
.
I think what happened was that when I got the Hydroedges put on
just about a year ago, the tire place [Hogan in Woburn, for the
record] replaced all the perfectly good Toyota-sourced valve
stems with some crappola offshore aftermarket ones simply because
they have this policy of always replacing valve stems along with
tires. They shouldn't have bothered. There's a growing body
of evidence (http://www.babcox.com/editorial/tr/tr20134.htm) that all valve stems are NOT alike and the ones that
tire places tend to buy in bulk are absolute sh!t.
.
The guy on the phone at Hogan was like "well, you've got that
lifetime valve warranty..." to which I retorted "that's not the
POINT! I'm not going to be coming back for an annual VALVE
STEM replacement, that's just silly." And they have no upgraded
options to give me, i.e. they put this garbage on every tire they
mount. Which means I have to go shopping for better stems that
fit these rims [and how to determine the specs, I have no
idea yet] and then take those to Hogan so they can swap them in.
.
I *knew* something was wrong when I immediately observed that
the new stems seemed a lot more flimsy/wiggly than the old ones
after the new shoes went on. Dammit, I should have raised high
holy hell right there and demanded the old stems back, but I
gave them the benefit of the doubt that they knew what they
were doing. Of course these were the same people who left the
car powered on the whole time they were doing the wheels and
then turned it *off* when they went to drive it off the lift.
Right up the hill from a Toyota place, too, and bloody LIED to
me when then claimed that they "do Priuses" all the time and
know all the subtleties.
.
Hogan corporate is in for a jolly ol' earful, lemme tell ya.
I don't want to start a 3000-odd mile road-trip on these things.
.
Why do all my tire issues come up in November?! First year it
was a screw, necessitating a patch; next year it was the new
Hydroedges, and now it's the valve stems. Weird.
.
Oh, and no, I don't think it's a pressure issue. Most stems
are rated for 60 psi [and thus could likely withstand more] and
I think I'm safely under that. But maybe long-term effects on
cheap stems ... hmmmm. Something we should all think about.
.
_H*

Can you buy some good quality stem (?from Toyota?) and have them install those for you? would be worth a few bucks for decent stems.

Dammit, I should have raised high
holy hell right there and demanded the old stems back ....
They likely would have come back to you in pieces. Unless things have changed since I was in the tire business, they use a specialized tool that grips the stem and breaks it off at the base.

Toyota is right down the hill from there, and I'm going to swing
by tomorrow so one of Hogan's Honchos can take a look at what's
going on. I'll compare the two brands of valve stems between
Hogan and the Toyota parts dept to see if I can at least pick
the lesser of two evils.
.
Hogan buys them in bulk, the guy said, from Mohawk Rubber. Now,
try googling for "mohawk" and "rubber" to see some really
exemplary keyword spam.
.
_H*

Okay, I think I've learned more about valve stems today than I
ever expected. There are many varieties of the standard "TR413"
snap-in type:
http://techno-fandom.org/~hobbit/cars/valvestem/413.jpg
designed to fit in a 0.453" rim hole, and rated for 65 PSI.
For light trucks and the like, there's a higher pressure "TR600HP"
type:
http://techno-fandom.org/~hobbit/cars/valvestem/600.jpg
with a heavier base inside the rim, rated to 100 PSI. The
interesting thing is that these type numbers and pressure ratings
are across all the manufacturers, and the real issue comes down
to what manufacturer produced a given batch of stems.
.
Long story shortish, I have four new TR413 valvestems. The guys
at Hogan were baffled as to why mine were starting to crack but
offered that possibly running at sidewall instead of 32 PSI
might have helped the process along. The funny part is I did
wind up getting stems from Toyota -- the Hogan guy gave me one
of his and I walked down the hill to the Toyota counter to see
what they had, and the parts guy and I stared at the two and
while they did look different, we couldn't determine any real
quality/flexibility/etc difference. I thanked him and started
to walk out and he stopped me and handed me the whole handful
of four, saying "think of us next time", so there I was with
four of whatever the Toyota place would use to do tires. They
did seem just a tiny bit shorter and stiffer than the ones from
Hogan, so I trudged back up the hill to show them all this and
we decided to go ahead with the swap and use the stems from
Toyota. They were cool with it either way, and I even got to
hang out in the bay and natter with the tech and puzzle over
what might have happened. He said he's been using these stems
for a long time and has never seen this sort of issue.
.
I saved a couple of the old ones. There *will* be a full autopsy
and discussion about a possibly hitherto unknown side effect
of running your tires at *really* high pressures. These things
are supposedly rated for 60 or 65 psi depending on which piece of
marketing literature you read. What sort of peak pressure do
you think is generated by taking a 50-something PSI tire over
a nasty bump??
.
Maybe what I *really* need is these:
http://techno-fandom.org/~hobbit/cars/valvestem/bolt.jpg
.
_H*

I finally put together all the rest of the details (http://techno-fandom.org/~hobbit/cars/valvestem/) on this.
I pretty much know the reason, but it makes me worry about
many of the other rubber parts around any car, especially
aftermarket, that could have similar problems.
.
Y'all will be happy to know that it's not an effect of high
pressure, for the most part, although perhaps part of an "extreme"
setup might be to change to higher-pressure valve stems. It may
be pretty much required by someone changing to 51 psi treads.
.
_H*

Hobbit, your site's pdf was also interesting on the topic of valve 'dust caps'. Lat Jan., I was fortunate to obtain 4 aluminum ones (w/internal o-rings) from Rainbow Tire in WV. All the others seem to be plastic and thus perhaps not so nice. What kind of caps do you have?

DAS

This is nice work H.
Enjoyed the right up on your page.
I would be interested in getting some of these clamp in valves also.
Group buy maybe?

Randall

Valve Stem Recall - pdf (http://nhthqnwws111.odi.nhtsa.dot.gov/acms/docservlet/Artemis/Public/Recalls/2008/T/RCDNN-08T018-8189.pdf)

-mr. bill

Great info. Thank you.
Maybe what I *really* need is these:

Very prudent idea. Rated for higher pressure, less likely to crack due to flexing. Especially when you consider that the longer life of the tires resulting from higher pressures will mean more rubber components exposed to the elements for a longer time.

I have made a point to let our tire shop know that I am happy to spend as much as $50 or so more for a set of tires with them since their service and advice has been invaluable. They tend to like customers like this, and they have provided very good advice on many of the tougher service jobs I have done myself. Since I get free lifetime balance/rotation with their tires, (and my tires are already lasting ~100,00 before my new max sidewall practice) I have had no problem getting them to change the normal type valve stems out every couple of years for the cost of the stems. I get a (free) fresh N2 fill while I'm at it too which helps evacuate all the regular very humid air I have put in at home.

Well, if you don't want the humid air in their, stop blowing them up by mouth! (kidding).

Rather than assume what might happen to a valve stem if your tires are pumped up and you hit a rut, this should be part of the original testing with the design of the valve stems.

My daughter hit a curb, and blew out both front tires, even bent the rims. The tire valves did not like a projectile go. They remained where they were designed to be. It was obviously within the factor of excess safety any valve stem manufacturer would be prudent to follow.

Well, if you don't want the humid air in their, stop blowing them up by mouth! (kidding).

oops. :o

I have had two valve stems blow this year. Cal Tire complained about a bad batch from China? H

So Harold, what caused the actual valve stems to eject?

Both stems split at the rim about half way around. I have two left on my snow tires and I am going to have them replaced when they are installed next winter. H

Both stems split at the rim about half way around.

I grew up in our family gas station changing tires, then spent another few years at a "major brand" tire dealership doing the same. Although I suppose you could have gotten "bad" stems, the failures you had sound an awful lot like they were "overpulled" with the stem tool during installation. This can easily cause tearing in exactly the spot you described. Don't ask me how I know.:o

The odds of an improper technique being applied to more than one tire in a set are much higher than the odds it was 2 "defective" stems that failed in a way that is usually caused by excess side deflection (hubcap misalignment forcing the stems to one side) or "stretch" (not sure how this could happen once installed?)

I'm resurrecting this old thread, because there's some new info
to add to it. Yesterday I was contacted by a local safety
advocacy consulting group, which interacts with NHTSA and other
gummint agencies regularly to investigate and follow up on various
safety-related issues. The guy from there had apparently found
my valvestem writeup and thought it was really useful for the
case he's helping put together. It seems that the same bad batch
from Dill has been responsible for at least one traffic fatality,
and he says the brown stuff is going to seriously hit the fan
on this soon. I can't really say more on it without knowing
more on it, but the phrase "cover up" has surfaced more than
once in the discussions.
.
What really sucks is that maybe I've changed out my own stems
which are holding up just fine so far, but that doesn't deal
with the THIRTY MILLION others that are still rolling alongside
me on the roads. This is really scary stuff.
.
It's been an interesting week so far. Interview with someone
from the christian science monitor on Monday, delivering my "why
hybrids are good" talk at BBN today over lunch, and then dropping
off the bad valvestems with this advocacy group later in the
afternoon -- I still had them, and they want to get them analyzed.
This led to a long interesting discussion about all kinds of
safety stuff in general.
.
_H*

eep ...
.
Channel 5 is coming to interview me about this TOMORROW.
.
_H*

Good luck with the interview!

Check out these links:
http://safetyresearch.net/Library/SRS067.pdf
http://safetyresearch.net/Library/dilltechblt.pdf
.
Dill didn't issue a statement on this until *MAY 2008*.
.
I could have been frickin' DEAD by then.
.
And we still have to worry about the other 29,999,996
stems that may still be rollin' out there.
.
_H*

ozone - dude global warming strikes again !

The interview went well today, and I captured some details (http://techno-fandom.org/~hobbit/cars/press/ch5-vs/).
The highest irony was finding some degradation on the valvestems
on *their* truck.
.
_H*

well documented hobbit, something for me to eye for when I'm doing my maintainence checks on customer's vehicles!

lol if i were you'd i'd bark at the tech to torque my ******* wheels, the hell did I pay you for? I certainaly do, but in my experience most flat rate dealerships don't. People tell me, "oh but I can feel the torque in my guns" and then others tell me , "BULL**** don't you know the compressor speed is variable? the pressure is never constant"

hm too much to debate, I just torque the damn wheels so I can be clean if something happens to them.

Any idea when they plan to run the story?

Sarah gave me a tentative of Monday sometime. I probably won't
be back home by then [not that I have a working TV anyways].
Some friends will probably try to record it, and I expect their
site will have an mpeg of the segment up for grabs.
.
_H*

I'll try to keep my eye out.

And Go Get Em this weekend. Bring it on home for Boston:woot:

I wonder, is this Discount Tire notice (http://www.dtccares.com/advisoryLetter.shtml) related to your work? I'm going to have to go and double-check my stems - I bought from them in April 2007. I haven't received the letter, though. I just want to be sure.

Time to resurrect this thread, but with a slightly different
reminder that still qualifies under the "check your valve stems!"
directive. Over the weekend, my indicator (http://techno-fandom.org/~hobbit/cars/tpms/) began suggesting that
the right rear tire was going a bit soft. Odd, since I had just
rotated the tires and re-aired them all a couple of days before.
Did I screw something up somehow? I had a couple of passengers
that evening, both sitting in the right side of the car, and
since a quick glance at the tire showed nothing amiss I just
attributed a minor difference to weighting rather than pressure.
It seemed to be a bit better once solo on the way home but it
was still registering a bit of difference between right and left.
.
Later I checked it and whaddayaknow, it was down under 40 psi.
I pumped it back up and started feeling for anything stuck in the
tread and listening for hiss; nothing obvious. But then, recalling
what I've experienced in the past, I wet my finger and stuck it
over the top of the valve stem. Sure enough, I felt a little bit
of pressure build which released with a little "pfft!" when I took
my finger away.
.
I got out my Schrader valve core tool and re-torqued the core
down into the stem, and the leakage stopped. I never actually
checked the cores before these replacement stems went into the
rims. The little conical valve-core gaskets evidently have
compressed a bit over the last year and all that's needed is to
back them off a little and then make sure they're screwed in to
the correct tightness. These are the replacement valve stems for
the ailing Dills from last year, and they're still fine around
their bases.
.
Many of us run pressures that are at or near the listed pressure
rating of our standard snap-in stems, which may put a little more
outward pressure on the valve body gasket. It's not particularly
surprising that those tiny seals compress over time and without
being reseated, may leak a little. I've seen this more than once
with bicycle tires, that's how I knew to look for the problem.
The valve cap can't entirely keep that sort of leakage in, either;
it doesn't seal well enough.
.
_H*

2 of the 4 flats my Prius had were due to the valve stems, one was probably what you just described, the other was a stem that cracked at the base (probably one of these we were warned about) The other two were usual foreign objects picked up on the road.

Good idea! Will have to check mine.

Thank you again, Hobbit, for pursuing this issue. I got my free replacements last month.

I'd heard somewhere to get truck valve stems next time I get tires. What about that?

That's feasible, read the writeup (http://techno-fandom.org/~hobbit/cars/valvestem/) for hints on what they look
like and how they're sold. They're not necessarily "truck"
specifically, just higher pressure and tougher. Bet they still
use the same little valve bodies inside, though.
.
_H*