Hacker News Reader

Comment by gmarx | Hacker News Reader

Charging customers for nitrogen filled tires that contain no more nitrogen than air (hey 78% is a lot!) reminds me of an idea I had to market regular salt as "ancient sea salt". I cracked myself up with this idea and thinking about the suckers in Whole Foods switching to it from their pink Himalayan or whatever regular sea salt.

Then I searched and discovered that of course some scumbag was actually doing it. Hehe

View on HN

I mean Pink Himalayan Salt is funny marketing too. “Pink Pakistani Mine Salt” just doesn’t have the same ring to it.

Where I live, Costco sells potato chips with salt inspired by ancient Himalayan salt which cracks me up every time.

Yesterday I bought some vegetable chips at the store. It contained one vegetable: potato.

don't forget about the beet juice used for coloring!

These ones didn’t even have that!

Most of the chips I've seen are guilty of this, from Trader Joe's to the popular Veggie Straws. They're essentially baked/popped chips with no extra nutritional content. "Veggie" is definitely deceptional to the average consumer, who expects vitamins and minerals.

I wouldn't call potatoes a vegetable, but they are nutrient dense. They are actually about the most well-rounded thing you can eat if you had to choose only one food to live off of. The only negative to them is the glucose spike, but if you have an active job, it's less of a problem

They are literally a vegetable

There is a legitimate use case for dry nitrogen in tires, it just doesn't apply to the average person's situation.

When the interior of the tire can become very hot, such as due to compressive loading in heavy construction equipment, there is a risk of accelerated oxidation and weakening of the tire material. In more extreme cases, the oxygen can react with atomized tire bits inside the tire causing an explosion via the same mechanism by which a Diesel engine works. It is exceedingly unlikely that the tires on a normal road car will ever become hot enough for this to matter.

I thought it was also about removing the water vapor which could condense out in cold conditions.

My limited knowledge comes from a former life where I was trained diesel mechanic for heavy machinery, and this was a specific part of our education. Cold weather was never a concern related to nitrogen.

The scenario everyone worried about, and was beaten into our heads, was a bit of oil or grease leaking into the tires, which is pretty normal on heavy equipment. Under typical conditions, this is harmless. However, under high compression that oil can start to vaporize, which basically turns it into highly flammable fuel. Under the right conditions this fuel when mixed with the pressurized air can and will spontaneously combust. Failures can be pretty spectacular, and they had video to prove it. The nitrogen removes the oxygen from the equation so that the combustion can never occur.

Apparently it happened often enough historically that it is mandatory practice in many domains. For me, this was received wisdom because I've never seen this kind of explosive failure in real life, which is a great thing. But if I put my chemical engineer hat on it also is eminently plausible, so I put it in the category of "lessons they learned the hard way".

I didn't know that scenario but I certainly could see it happening. Oxygen under enough pressure becomes a pretty nasty oxidizer. Especially when it happens suddenly. (Open the valve on a high pressure oxygen tank, pressurizing a system that wasn't previously pressurized.) By the time you add enough heat to the mix--rocket engines always run fuel-rich because at those temperatures an engine that runs oxygen rich probably then runs engine-rich. If you burn an engine to fuel exhaustion you likely destroy it.

Some bottled water brand had a tagline "no other water hydrates better"

in case anyone does want to use nitrogen in their tires, I think at least US Costcos with tire centers have free self-service nitrogen inflators for members.

Speaking of bottled water, guess what Evian is spelled backwards...

What?

Underrated joke

Nivea.

well, not all liquids hydrate the same. Some even de-hydrate (coffee, seltzer water etc.). The water you're drinking is not pure, it always has some impurities which affect how much you hydrate drinking it. Pure water (distilled) is "undrinkable" for humans. I can see how a water with ions and whatnot (like a gatorade) can hydrate and replenish your electrolytes better.

> Some even de-hydrate (coffee, seltzer water etc.)

This is mostly a myth. Water hydrates you regardless of whether it's mixed with CO2 or with coffee beans. The thing about caffeine is that it is also a diuretic, so some of that water will be quickly expelled.

But then why do they use saline instead of (relatively) pure water in IV bags? I would think it's fair to say there's some sweet spot when the goal is hydrating the body, though I doubt it's what the slimy advertiser above was intending to convey.

They use saline instead of pure water because it's isotonic with respect to serum/plasma. i.e. you're not going to go into electrolyte imbalance if a lot of it is put into your blood.

Normal saline is about one-quarter the concentration of sea water, by the way.

here I thought I was saving cash by injecting sea water

They use saline because it goes directly into your blood stream. If they used pure water, the osmotic pressure would force water into your cells, causing them to burst (hypotonic).

You can drink pure water because it "becomes" saline as it mixes with the food in your stomach.

Even unfiltered tap water doesn't have very many ions compared to blood or saline solution. Most of your ions come from your food.

Coffee will hydrate you. The amount that you expel from the caffeine is typically less than the amount you have taken in.

There is such a thing as osmolar pressure. Simply put, water wants to dissolve things and it goes wherever the solute is. High enough concentrations of solute in the intestines cause actually cause water to leave body instead of being absorbed, often causing diarrhea. Oral rehydration solutions consist of water with appropriate amounts of sugar and salts such as sodium and potassium.

There are very simple experiments you can perform to demonstrate this phenomena. Grab plants or something similar and put them inside three different solutions: hypertonic, isotonic and hypotonic. There will be interesting results.

https://en.wikipedia.org/wiki/Osmotic_concentration

https://en.wikipedia.org/wiki/Osmotic_pressure

https://en.wikipedia.org/wiki/Osmosis

I don't know where you're getting your science from, but seltzer water is not dehydrating, and distilled water is not undrinkable for humans.

At best you can say that if you consume exclusively distilled water for a long time, you might deplete your body of some minerals unless they are replenished another way.

I didn't mean it as a direct consequence. Seltzer water will de-hydrate people that have bladder sensitivity to acids (like myself).

Also, the purpose of the " in the "undrinkable" statement was to make it clearer that it's about people considering it "undrinkable", not that it's toxic or it doesn't hydrate. You just wouldn't drink distilled water unless you were dying of thirst in the desert.

AFAIK the only solution in water that actively dehydrates you is a strong salt water (roughly, sea water). Others (e.g. coffee) are just not as efficient at hydrating you due to diuretic effects or whatever.

it depends, if you irritate your bladder through the ingestion of coffee or acids(it's a thing for some people, including myself), it might actually de-hydrate.

My local Costco doesn't check for membership at the tire pumps. YMMV.

Sometimes you can also sneak in the exit and buy yourself a hot dog.

Don't know about the states, but in Canada, you don't have to be a member to use the pharmacy, that gets you in for samples and everything.

Plus, their pharmacy is a great deal.

This is true, but if you run into an officious gatekeeper, they will block you 'while they get the approval of the manager' before they will allow you to proceed. I hate going to Costco stores generally but their online operation is generally awesome, including prescriptions by mail.

I think this is true in the US as well. And possibly liquor in some states (meaning a subset of the states that offer it in the first place).

There's no sneaking, you can go buy a hot dog without a Costco membership.

(Vegetarian here, who also doesn't like cheap-ass pizza, so it is possible this has changed in the last few years without my knowledge.)

Just before the pandemic blew up in the US, Costco changed its rules to require showing a membership card to access the food court. (You still don't have to scan a membership card to use the food court kiosks, just show it to get in the door.)

https://www.latimes.com/food/story/2020-03-03/costco-food-co...

In locations with the food court outside, they generally scan it when ordering at the food court window or at the kiosks.

I once saw a big display in my local grocery for "organic salt" a few years ago. Which struck me as just fundamentally wrong. We are talking about non-organic material. Of course they meant "organic certified" which just meant they didn't includes additives. But still ... it seems so misleading.

I think the point of “nitrogen” is more that it’s dry and impurity free, vs shop air that can have a lot of moisture and other junk in it. Ever drain an air compressor tank off the water that accumulated inside? They get filthy with rusty water.

That's not the pitch that is made for the stuff.

And I'm not sure that I've ever heard of rim failure due to filling air moisture being a widespread issue.

> That's not the pitch that is made for the stuff.

I mean, how often do salespeople understand the technical details of what they are selling?

True. But you almost never see any significant amount of that in tires.

That's true, although you should be draining them to remove water frequently enough (just to keep it in good health) that I wouldn't have thought it'd make much of a difference

Draining the water doesn't mean what comes out isn't at 100% humidity--and thus can condense out water if the temperature drops enough.

(Which doesn't mean that it isn't total overkill to use nitrogen rather than just dry air.)

> Charging customers for nitrogen filled tires that contain no more nitrogen than air (hey 78% is a lot!)

Are dealerships claiming to use nitrogen and just pumping in regular air, or are you talking about the unnecessary upselling of it? It's common in racing to use nitrogen, but yea, totally unnecessary for a Camry or whatever. One of my cars displays a warning telling me to visit the dealer when the tire pressure is low because the manufacturer recommends using nitrogen. I laughed the first time I saw the message on my gauge cluster before I knew the reason...still a ridiculous thought going to the dealer to top off my tire pressure even for nitrogen.

> totally unnecessary for a Camry or whatever.

Forget the Camry, it's hard to construct a road use application that actually makes sense. I guess you can be a bit more relaxed about checking during seasonal changes....

> Forget the Camry, it's hard to construct a road use application that actually makes sense.

For daily driving, sure, but a lot of people track their cars. I don't care about nitrogen in my tires because I'm hardly a competitive racer or frequent track-goer, but for owners of "from the factory" track cars like the ZL1 1LE or GT3 RS I'm sure it matters more to them.

As I said, "road use". Applies to most track days too, really. Maybe if you are club racer with a dedicated (i.e. trailored) track vehicle.

Right, I meant that people often track their street cars. I've already said that I don't bother with nitrogen, but it takes a special kind of person to run R compound tires on the street...

Sure but people that track their street cars are rarely seeing any real benefit from nitrogen, either. It's a pretty marginal thing. Vast majority of people going to track days hit their own limits well before getting anywhere near the equipment limits.

The use case is that once given bigger air molecules, customers will come back to the shop to top off on said molecules.

That gives the parts guy the ability to peddle $75 windshield wipers and gives the sales manager an opportunity to pitch the customer to buy/sell the car.

For Costco, it’s perceived value. “Wow, I get my magic air and aren’t spending $300 every time it fill it!”

I had forgotten that this was done in racing but can't imagine why you would want this for a commuter vehicle. I assumed they were just adding a line item to the bill and nitrogen made it sound more legit. But now that you mention it maybe they were offering to fill the tires with nitrogen like in the race cars but then just using regular air because really how would the customer know?

The argument is that Nitrogen would have lower moisture content than air, and that allegedly reduces corrosion in the tires and wheels.

Also Nitrogen filled tires lose pressure more slowly, because Nitrogen molecules are larger. The difference is not significant.

> Nitrogen molecules are larger.

That's what they told me at the dealership too. I asked "larger than what? Air is a mixture that's already 78% nitrogen." Didn't get an answer.

As far as the lower moisture content, couldn't they pass the air through an air dryer before filling the tire if it was that much of an issue? Regardless, the outside of the tires & wheels are exposed to far more corrosive materials.

>That's what they told me at the dealership too. I asked "larger than what? Air is a mixture that's already 78% nitrogen." Didn't get an answer.

No idea about molecule size, but the reason for nitrogen is that it expands less than air when heated, so tire pressure doesn't change as much when driving hard on a track.

> As far as the lower moisture content, couldn't they pass the air through an air dryer before filling the tire if it was that much of an issue?

Yes, this point is some dealership BS. Pretty much every auto shop will have a dedicated air line for filling tires, if not the whole system with an air dryer.

When I was a pro mechanic, the whole compressed air system had moisture removal, because I don't want that shit in my air tools, either. I don't know about Costco, but of the shops I know of, it's one big compressor for tools, tires, etc.

> >That's what they told me at the dealership too. I asked "larger than what? Air is a mixture that's already 78% nitrogen." Didn't get an answer.

> No idea about molecule size, but the reason for nitrogen is that it expands less than air when heated, so tire pressure doesn't change as much when driving hard on a track.

Pressure/temperature/volume for any gas are governed by the ideal gas law, which doesn't care what your molecules are.

(Sure, it's an approximation, but certainly one that's imperceptibly reliable enough for car tyres).

We've been selling nutritional supplements online for over a decade and I remember reading once about how some dirt on food really helps the microbiome. I considered selling dirt pills for a while. I think we'd have some success.

"Nitrogen. It's what tires crave!"

Reply on news.ycombinator.com