Tires seem to require very frequent air addition?

[gearchruncher]

I've found that using that has yielded more stable tire pressure than just standard compressed air.

Selection bias. 100% Nitrogen follows the laws of physics just like 78% Nitrogen and 21% oxygen does, and adding 5 PSI of 100% nitrogen to a tire that is already full of "air" barely changes the internal ratio.

https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=191

 

[E.Potter]

damn...I keep my pressure around 47 PSI

 

[E.Potter]

oh BTW...adding air to tires that have been " driven on"/warm tires...they will soon deflate to a lower PSI...try to add air when the tires are colder....if you HAVE TO add when you have hot or warm tires...inflate them about 3 PSI than you normally would so that as they come down, it will be closer to where you want the number to be.

 

[rpiotro]

Selection bias. 100% Nitrogen follows the laws of physics just like 78% Nitrogen and 21% oxygen does, and adding 5 PSI of 100% nitrogen to a tire that is already full of "air" barely changes the internal ratio.

https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=191

I have a 78% Nitrogen fill station right here in my garage!

 

[MikeyC]

I have a 78% Nitrogen fill station right here in my garage!

Me too. And if it's true that oxygen leaks more than nitrogen, then more oxygen will leak out over time and eventually you may be at 85% nitrogen, 90%, 95%.

Mike

 

[KenC]

I have a 78% Nitrogen fill station right here in my garage!

Where I live we call those O21 nitrogen fill stations.

 

[Midnightsun]

Only advantage is nitrogen is thicker than air so you can go a little longer between topoff having less escape through the rubber. As mentioned, the Nitrogen percentage is not all that much compared to regular air so the benefits are rather miniscule. Huge marketing hype is all it is/was.

Got a good laugh out of this one. Top 10 Reasons Nitrogen Filled Tyres Are a Scam — Auto Expert by John Cadogan - save thousands on your next new car!

 

[DocHolliday]

I have the same model purchased around the same time, also garaged in CA. I topped the tires up once a couple months ago from 39/40 to 42. Other than that they are pretty stable. Currently showing 41/42 when warm and no TPMS warnings.

 

[E.Potter]

being lowered...I HAVE TO keep an eye on the tire pressure every week... I like it around 43-47

 

[gearchruncher]

being lowered...I HAVE TO keep an eye on the tire pressure every week... I like it around 43-47

What does being lowered have to do with the rate at which you keep an eye on pressures, especially if your acceptable pressure range is already 10%?

 

[E.Potter]

What does being lowered have to do with the rate at which you keep an eye on pressures, especially if your acceptable pressure range is already 10%?

Tire wear with negative camber...better to keep it puffed up

 

[gearchruncher]

Tire wear with negative camber...better to keep it puffed up

That's not how it works. The higher the pressure in the tire the smaller the contact patch, and the more wear put on a smaller portion of the tire. Your tire will wear faster with high camber at higher pressures.

But none of that explains why you need to keep a closer eye on your pressures than a non-lowered car, especially with TPMS.

 

[E.Potter]

I wouldn’t say the higher the pressure… I would say the higher the pressure to an extent…

Because very inch counts man… I’ll freaking scrape the speed bumps if I don’t keep an eye on the pressure…lol especially in my neighborhood…

 

[MikeyC]

Only advantage is nitrogen is thicker than air so you can go a little longer between topoff having less escape through the rubber. As mentioned, the Nitrogen percentage is not all that much compared to regular air so the benefits are rather miniscule. Huge marketing hype is all it is/was.

Got a good laugh out of this one. Top 10 Reasons Nitrogen Filled Tyres Are a Scam — Auto Expert by John Cadogan - save thousands on your next new car!

The only thing positive I can say about a nitrogen fill is that it is "dry" gas. You don't get the moisture you get from air. But if you have a good compressor, they can take out most of the moisture. I never worry about it. It takes maybe 7-10 minutes to top them off once every couple months.

Mike

 

[E.Potter]

The only thing positive I can say about a nitrogen fill is that it is "dry" gas. You don't get the moisture you get from air. But if you have a good compressor, they can take out most of the moisture. I never worry about it. It takes maybe 7-10 minutes to top them off once every couple months.

Mike

cool..good to know...learn more and more everyday...you guys ROCK!!!

 

[Dayoldpoi]

Just posting here to see if any one else is encountering this weird phenomenon.

Wife bought a 2021 Model 3 Performance in August 2021. Since then we've only put 3,000 miles on the odometer with mostly freeway driving and errands (aka no track days). Stock uberturbines and tires. I'm in Northern California and the car is parked in a garage. So maybe it's gotten down to 40F but this thing has never seen snow.

The tire pressure keeps dropping from the factory 42 psi down to 36 psi every 1,500 miles. And it's every tire coming down in pressure at the same rate. All 4 basically went down to 36 psi a few months, and the TPMS warning (orange indicator) popped on. I got a Milwaukee 12v digital air compressor and roadside patch kit since the Model 3 doesn't have a spare. I've already used it to refill all 4 tires from 36 to 42 psi, and now I had to do it again.

I've owned a bunch of cars leading up to this, and I've never seen this. IIRC back in the 90s, there was a push by stealerships to put nitrogen into tires to help keep this from happening, but that was a load of baloney. Regular atmospheric air shouldn't be leaking this fast.

Is this normal for all of you with Model 3 Performance? Like you just gotta keep topping these tires up?

I have the same issue and have to refill tires every few months.

 

[rwiegand]

Rate of pressure loss is pretty dependent on the size of the tires. (probably actually the surface area to volume ratio). Skinny tines go down pretty quickly (like a pound a month or more), the big tires on my F350 can go a year without dropping a pound.

 

[3sr+buyer]

1psi per month is fairly typical of tire air pressure loss.

However, this tire air pressure loss can be counteracted in the spring as temperatures rise, and accelerated in the autumn as temperatures fall.

 

[Chattanooga3]

Temperature change?

This, and it should be common knowledge for car guys and deflategate football fans...

 

[comanchepilot]

1500 miles? In a Tesla with42PSI tire pressures? Perfectly normal.

My wife has an S and I now have a model 3 Perf - that seems normal to the point of abnormal in that the highrer pressures in the tires should leak down faster than that. Most vehicles are betw 32 & 36psi with 33 being more or less average. Given that sea level pressure is 15psi - the difference between 15 and 33 is 2.2 whilst 42 and 15 is 2.8 - so there is 28% more air pressure trying to get out -