On Wed, 28 Nov 2007 08:03:12 -0800, SMS ???• ?
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[email protected]> may have said:
>The automobile wheel and tire is very different than the bicycle wheel
>and tire. There is no tube used on automobile tires, the wheel is
>usually made of steel rather than aluminum, the pressure is much lower,
>and the volume is much higher.
While steel is still the most common material, aluminum is gaining
ground due to weight considerations. This is not always to the
consumer's benefit. Automotive experience is that properly
manufactured aluminum wheels are no more susceptible to leakage than
welded steel; the gas mixture issue there is irrelevant. As for
pressure stability, those of us who do a lot of highway driving can
tell you that temperature-driven pressure fluctuations in properly
air-inflated tires are tiny indeed. In a memorable instance, I
started the driving day at 46F in Flagstaff, AZ with 32psi in the
tires of my Taurus, and later that day at near 100F in Bakersfield,
CA, they were at just under 34psi. That is not enough change to
matter. Those tires had never seen a nitrogen fill in their service
life. Although the fluctuation range would be greater if significant
water was present in the tire, most compressors are equipped with a
moisture trap to reduce this, and here in humid Houston it is not
common to find any significant liquid water inside a freshly demounted
*cold* tire. (I could not have said that 25 years ago, when too many
gas stations had a "free air" hose that was connected to a compressor
whose water drain had last been opened during the Korean War.)
>If the question is "is there an advantage to using nitrogen in bicycle
>tires?" then the answer is no.
100% correct.
>For automobile tires, there are
>advantages, though if you're someone that routinely checks your tire
>pressure then the advantage is minimal.
In point of fact, for the ordinary automotive user overall, the
advantage is nil. For the tire store that wants to ensure that the
customers come back regularly, although there might *appear* to be an
advantage in promoting the N2 fill, the reality is that actively
touting it will cause drivers to avoid checking the pressure and
inflating to spec until they are where they can get the boutique gas,
instead of checking it regularly and filling from any available
compressed air source. One local tire store manager already has run
into this mentality in customers quite a number of times. Any barrier
that is placed between the customer and proper maintenance will cause
the maintenance to be neglected, period.
>Since Costco has the lowest tire prices by far,
Not around here.
>with the lowest charge
>for balancing, no charge for valves, and no charge for road hazard
>warranty, it's probably the the cost of them including nitrogen
>inflation at no extra charge must not be very high.
It's not high, but it's pure fluff from a reality-check standpoint.
The customers will derive no measurable benefit from it.
>Also, it reduces
>warranty expenses from customers that don't maintain proper inflation.
How? It does not change the inflation loss rate to any measurable
extent. This is based on trucking industry experience at the
maintenance shop level, where several large fleet users tracked their
results and found zero difference in pressure drop rates after
swapping to an N2 fill, both for their large and small units. What
they did note was that underinflated tires no longer exploded when
they got overheated in use; they had less dramatic failure modes with
N2. It should be noted that the policy of the fleet shops where I
still have a contact remains "keep the pressure at spec by any means
available; if you top up a tire with air, note it in the log; if it
drops significantly on a single run or day, flag it when you hit the
terminal." They regard keeping the tire *inflated at all* to be more
important than what it is inflated with.
>Since unlike most tire stores, Costco actually does honor the
>manufacturer's tire warranties, they have a vested interest in reducing
>warranty claims.
You have poor tire stores in your area. I have had no problem getting
manufacturer warranties honored here in the few instances in which an
actual warrantable defect was involved. Outside of Firestone tires,
however, I can't recall a warrantable failure from among my own
vehicles in at least ten years. I've had them on other people's
vehicles, twice in that time. (One was a sidewall bubble that formed
within a week after the tire was installed, and another was a slow
leak due to a malformed bead that should have been caught and rejected
at any of several points along the way.) Nearly all in-service
automotive tire failures are related to either underinflation,
overloading, misalignment, or road hazard, and virtually all of these
display specific identifiable failure modes that identify the cause.
I will note, BTW, that Costco honors the warranty only for the tire
brands it sells, just like any other tire store. To the customer,
Costco's in-house road hazard policy makes the warranty issue hard to
identify as a separable thing; the tire gets replaced, and it's up to
Costco to decide if they file a claim with the manufacturer or not.
If, as a means of building business, they are "honoring" the
"warranty" on a tire not purchased from them that has failed due to a
non-warranty cause, that's a PR move. It will bite them in the long
run, as the manufacturers will send reps around to educate their
personnel in what is and isn't a genuine defect-related failure if
they have an overly large warranty claim rate..and if, as would
doubtless be the case, an inspection of the removed tires reveals that
they were largely not warrantable-issue failures. I doubt that they
will encounter this, however, as I have never seen them actively
advertise for failures to be brought to them, and most people will
take a failure back to the store where they got it. If that's NTB,
good luck to the tire's owner. If it's Discount Tire (which isn't in
a lot of states), they'll probably still be a customer the next time
they need tires.
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