Nitrogen in tires

Another, "We also used an oxygen analyzer to be sure we had 95-percent nitrogen purity in the tire"

 

Having an intellectual discussion, displaying ones superior search engine and exceptional debating skills keeps the mind sharp, and let's face it, can be fun too . However the subject of proper Tire PM is common sense, which means this discussion amounts to classroom exercise about widgets.

Here's an idea. Just check your tire pressure routinely once every week or two. If you don't want to get your hands dirty, Discount Tire, NTB, Firestone, Goodyear, ect. will all check and adjust it for you...and it's FREE. You'll have to pony up for the rotation, balance and alignment though. Correction...you can rotate the wheels yourself.

 

If it is common sense, why isn't it more common?

 

That is a very good question.

Additionally, why do people call a service to install the spare when they get a flat? Why do people pay $100 for someone to change their oil? Why do people get mad when the car breaks if it's maintenance free. Why do people pay 5$-$100 for someone to wash their car? Why do people eat at McDonalds instead of cooking at home. Why do other Countries call Americans lazy?

What do I know?

 

^ Too true.

Why save money, get excercise, learn a skill? Everyone has their ceiling, but getting a little closer to it never hurt.

 

Here is some interesting info from Popular Mechanics. I was trying to Google "average tire leak rate per year" and these guys say up to 1 psi per month = 12 psi per year. I am thinking that is reasonable.

1. The tire-pressure monitoring system (TPMS) in my new car makes sure my tires are adequately inflated.

The truth: TPMS isn't required to issue a warning until pressure is 25 percent below the vehicle manufacturer's recommendation. That's "well below the pressure required for safe driving," according to AAA and "barely adequate to carry the vehicle's maximum load," says the Rubber Manufacturers' Association. TPMS is intended as a last-minute warning before imminent tire failure, not as a monitor to make sure your tires are properly inflated.

Buy a quality tire gauge and set your tire pressure to at least the vehicle manufacturer's recommendation, which is found on the driver's door jamb. I'd rather you set your tires 3 or even 5 psi high rather than 1 low. Tire-pressure gauges can be inaccurate, and tires leak as much as 1 psi per month. Higher pressure improves hydroplaning resistance and, if you're like many folks, you may not bother to check your tires again for six months.



Read more: 6 Common Tire Myths Debunked - Popular Mechanics​

 

I doubt that I have had tires that leaked as much as 1 psi per month in years unless they had a nail or screw in them.

 

TPMS indication is nothing more than an "oh sh-t" light. It means fix me now.

 

It is unfortunate that Toyota didn't make the actual pressure readout available to the driver. The system knows the individual tire pressures, it just won't tell us without a Techstream like device.

 

"The truth: TPMS isn't required to issue a warning until pressure is 25 percent below the vehicle manufacturer's recommendation."
But if you reset the system after raising your tire pressures above the manufacturer's recommendation, it will use the new pressure as a benchmark, thereby giving you a cushion. I've only had it trigger once, when I got a small staple-like piece of metal in a rear tire. The tire still had 35 psi cold, which was enough to get home on. I think it triggered at less than a 25% loss, as I was running 40 psi, which would have had to drop to 30 psi to be a 25% loss.
I agree that an actual pressure reading on each tire, as some cars have, is a much better system. But I don't rely on TPMS, but rather check my tires every couple of weeks. I keep an air storage tank in my garage for topping off. I do seem to lose about one psi per month, as was mentioned by another poster. (Maybe a little of that is caused by checking it so often.)

Read more: http://priuschat.com/threads/nitrogen-in-tires.123642/page-3#ixzz2OOuLDHTo

 

I haven't read this whole thread.

But simply my reason for not recommending or pursuing a "nitrogen" fill in my tires is convenience.

I like the ability to check the pressure myself, then use my personally owned compressor to fill my tires with good ol' air. Not being tied down to trying to make sure it's Nitrogen or going to a specific place to have it checked and filled all the time is a huge benefit IMO.

I think being able to monitor and maintain the pressure in my tires is far more important than what I'm filling it with. Any temperature, or stability benefits easily get trumped by these realities.

 

Here is a cool tire parameter (volume/etc) calculator
TRC Calculator

 

OK did some calcs, assuming approx 10-psig per year base case leak rate

A. Filled to 40 psig with Air - leaks down to 30.6 psig in 1-yr
B. Filled to 40 psig with N2 - leaks down to 32.8 psig in 1-yr
C. Filled to 40 psig 95%N2 - leaks down to 33.3 psig in 1-yr (optimum)

After 3 years - maintaining 40 psi by adding air:
Case A (air): If you maintain pressure every 4 mo. then the %O2 drops down to about 14-15 O%
Case B (N2): Assuming you could get 100% N2 in the tire, the O2 holds <7-8% O2 for slower leak rate
Case C (95% N2): Starts out good but eventually O2 content gets up about >10%

Bottom line, if you start out with 95-100% N2, you still see most of the benefits of better pressure maintenance even if you refill with regular air. Also, after about 1-2 yrs, even if you filled with air, the O2 content is lower, so your leak rate approaches the N2-filled case. In other words, the best time to fill with N2 is during the first filling. After that, you can use air, especially if the first filling can be ~100% N2 (eg; fill and purge, refill).

Although oxygen initially permeates faster than N2 through the tire at 21% O2, at somewhere around 5-8% O2 content there is no longer driving force (partial pressure differential) for O2 to leak out at all.