Nitrogen in tires scam

[Clare Snyder]

I wasn't disagreeing with you - jast making the comparison between atmospheric air and "dry" nitrogen.

[Clare Snyder]

New car tires are inflated to the pressure recommended on the door sticker or the dealer didn't do the pre-delivery inspection you paid him for. I've PDId hundreds of cars in my lifetime.

[Clare Snyder]

Also true of domestics. High pressure for riding on the train or truck to destination. I've done hundreds of PFIs on both domestic and imports.

[Jim Joyce]

A couple weeks ago my wife took her Kia to the dealer for some maintenance items under warranty. The car came back with 38 psi all around. The recommended pressure is 34 psi, which is where I had it.

[sms]

Costco doesn't charge extra for nitrogen. They buy it in such large quantities that the cost is lost in the noise.

Costco has a big incentive to include nitrogen inflation because they also include the road hazard warranty, it's not an extra cost.

One of the biggest causes of tire failure is under-inflation and one of the biggest benefits of nitrogen is that it doesn't leak out nearly as fast. I'm sure you're aware that many people never check their tire pressure and ignore the TPMS light. The TPMS sensors only last about 7 years before needing replacement because the battery goes dead. Fortunately many newer cars have figured out how to monitor tire pressure without those sensors.

It's a scam if you're charged more than an extra dollar or so for nitrogen. But Costco already has the lowest prices on tires and installation. If they are building in 25¢/tire for the cost of nitrogen then that's fine.

[Arthur Conan Doyle]

I prefer to run my tires at the tire limit rather than the usually softer sticker numbers for fuel economy. I think the wear pattern is a little more even as well.

[dpb]

Well, the NTSB study linked to above shows that the difference in leakdown rate is only about 25% higher for air than N in the initial 90 days of a new fill; on the longer term its only half that or so because with time the preferential N ratio goes up with air and down with N so they reach an equilibrium eventually near the midpoint between...and air is nearly 80% N to begin with, anyways.

I know nuthink about the effectiveness of Costco pricing have none within 200 miles. The cost for any facility isn't in the N itself, anyways, it's the labor and equipment for the purging process that's where the cost lies to them.

If they think they see a payback owing to reduced failures, that might correlate with the longer-term result of the above study that seemed to show benefits not so much from the deflation issue but to apparently reduced rubber deterioration from less oxidation for tires kept for three years.

Then again, unless they're running or have run controlled experiments to test the differences, it may just be an advertising gimmick they think brings in enough sales to justify.

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[invalid unparseable]

My dealer is inflating tires 6 psi above recommendation at service intervals. I believe it is due to those damn legislated TPMS. I don't know if the weakened battery life is extended. Once the battery goes the light comes on. Batteries are only said to be good for 5-10 years and replacement on all tires can cost in excess of $400.

[dpb]

On 3/18/2020 12:02 AM, Clare Snyder wrote: ...

Good point; the tire is then effectively the compressor tank...use one of them so rarely was thinking only of the compressor scenario above.

[gfretwell]

Never fooled with one of those. I have two 3HP (real not "Peak" or whatever the salesmen say) compressors. One is shop air, the other is just a spare right now.

[Clare Snyder]

I run mine at 38. Either your gauge is out of calibration or theirs is? Perhaps?

[Clare Snyder]

Most tire places don't BUY nitrogen - they extract it. They have a machine twice the size of a compressor that coincentrates it out of the air - lust like home oxygen machines concentrate oxygen out of the air for O2 therapy

[Clare Snyder]

The tire limit is generally WAY too high, but somewhere in between is best. I generally run at 36-38 where spec is 28-32 and tire limit is

50-ish

[Clare Snyder]

When you "air up" on the road, better than 95% chance you are running tankless.

[Jim Joyce]

I use either of two handheld gauges, plus the onboard TPMS. Those 3 all agree with each other. I guess that doesn't mean they're accurate. It's probably more likely that the dealer's gauge is inaccurate, but I think it's even more likely that they just pumped them up because it's something they always do. I don't know. That was the first time we used that dealer.

[Arthur Conan Doyle]

I agree 50 is way too high. Tire limit on my vehicles has been 6-8 psi higher than the frame label.

[invalid unparseable]

Looked up machines and they are pricey:

I believe they work on osmotic filter membranes vs the oxygen concentrators that rely on zeolites.

[Wade Garrett]

Do you experience abnormal center-tread tire wear running that much above the recommended pressure?

[Clare Snyder]

Not at all. And I don't get the edge wear I get at the lower pressures. On my truck I run LOWER pressure - but the tires are WAY bigger than stock. 235 70 16 in place of the stock 205 70? 14 inchers. I run about 2psi under placard pressure there or it rides like a lumber wagon. (they can be down to 20PSI and you can't tell by looking at them)

[Wade Garrett]

That's certainly not what