RX - 3rd Gen (2010-2015) Discussion topics related to the 2010 - 2015 RX350 and RX450H models

Nitrogen Filled Tires

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Old 06-03-14, 08:04 AM
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2008M3
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Those inexpensive air compressors won't get you a digital readout of the air pressure so you will never get it exact.

Where can we get a inexpensive air compressor with a digital read out?
Old 06-03-14, 08:42 AM
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2thfxr
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Clearing the Air About Nitrogen Tire Inflation


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H2 O2One of a tire's primary tasks is to carry the weight of the vehicle. But anyone who’s ever had a flat tire knows that the tire doesn't really carry the load...the inflation pressure inside it does! Using the correct inflation pressure not only provides the appropriate load capacity, it also enhances the tire's performance, durability and contribution to vehicle fuel economy.

Tires are typically inflated with air that’s a combination of roughly 78% nitrogen (N2), 21% oxygen (O2) and 1% miscellaneous gases. And since all gasses expand when heated and contract when cooled, tire inflation pressures rise and fall with changes in temperature by about one psi (pound per square inch) for every 10° Fahrenheit change in temperature. This is one of the reasons it’s recommended that tire pressures be checked early in the morning before ambient temperatures, the sun's radiant heat, or the heat generated by driving causes the tire pressure to rise.

And while tires appear solid, if you could see their microscopic structure you would find that rubber looks a bit like strands of cooked spaghetti stuck together. These molecular strands continuously stretch to and from their relaxed state every time the tire rolls and conspire to allow some of the gas to escape through the microscopic spaces between the rubber molecules (called permeation or diffusion). It's been estimated that up to one psi of pressure may escape each month a tire is in service.

Fortunately compressed air is often available at gas stations, tire stores and auto repair shops. Sometimes it’s free, while other times it’s only available from coin-operated compressors. Unfortunately the compressed air often provided contains varying degrees of moisture depending on relative humidity and the compressor system’s ability to dry the air by removing moisture.

So what can we do to help maintain more constant tire pressures? We could change what we inflate our tires with.

Pure nitrogen has been used to inflate critical tire applications for years, primarily because it doesn't support moisture or combustion. These include racing tires (IndyCar, Formula 1, NASCAR), aircraft tires (commercial and military) and heavy-duty equipment tires (earthmovers and mining equipment). The challenge facing nitrogen inflation hasn't been its application, it's been its method of supply and cost.

Nitrogen molecules have a more difficult time escaping through the microscopic spaces that exist between a tire's rubber molecules. Nitrogen is a "slow" inactive gas labeled as an inert gas due to its nonreactive nature with many materials. Oxygen on the other hand is a "fast" active gas that reacts with many materials called "oxidation." Additionally nitrogen is a dry gas that doesn't support moisture while oxygen combined with hydrogen makes water (H2O).

What are the effects of using pure nitrogen to inflate tires?
•Nitrogen is a gas and is still affected by changes in ambient temperature (about one psi for every 10° Fahrenheit). Nitrogen filled tires will require pressure be added during the fall/winter months as ambient temperatures and tire pressures drop. Nitrogen is good but can't change the laws of physics.
•Nitrogen reduces the loss of tire pressure due to permeation through rubber over time by about 1/3. This helps maintain the vehicle's required tire pressures a little longer, but doesn’t eliminate the need for monthly tire pressure checks. This is good for people who don’t maintain their vehicles well.
•Nitrogen is non-corrosive and will reduce oxidation and rust due to the absence of oxygen and moisture. This will help minimize wheel corrosion to promote better bead sealing. Tires that are used routinely will be replaced long before any life benefit would be received by using Nitrogen. This is most beneficial for drivers who drive their vehicles infrequently (car collectors, track drivers, snow tire users, motor home owners, etc).
•Nitrogen is a dry gas and will not support moisture that could contribute to corrosion of the tire’s steel components (bead, sidewall reinforcement and belts) due to the absence of moisture over extended periods of time. However it’s important to remember that atmospheric pressure is constantly pushing oxygen and moisture into the rubber from the outside of the tire. This is especially good for low mileage drivers who don't wear out their tires quickly or those that run average annual mileages but use long wearing radial (60K and 80K warranted) tires.
•Nitrogen assures more consistent pressure increases due to increases in operating temperatures in a racing environment because of the absence of moisture. This is especially good for participants in track days, high-performance drivers education schools and road racing.
•Drivers should use standard air if pressure adjustments are required when a local source of nitrogen can’t be found during a trip. While this reduces the benefit of higher nitrogen content, it is far better than running the tires underinflated in search of a source. Often the original nitrogen provider will refill the tires for free or a nominal cost when the driver returns to his hometown.

Several service equipment manufacturers have developed small, on-site nitrogen generator systems that use the selective permeation principle to separate oxygen and moisture from the shop’s compressed air lines to capture nitrogen. The key component is a membrane that separates the gasses. Each module contains hollow fibers that allow the oxygen and water vapor to be selectively removed, resulting in a source of nearly pure nitrogen that is kept in a separate storage tank until it is used to inflate tires.

The nitrogen generator, storage tank and filling system aren’t free and the dealer is entitled to some return on his investment. It’s time-consuming for a technician to bleed air from the tires (sometimes requiring several purges during the initial inflation) to achieve the desired nitrogen purity, however some of the latest equipment automatically goes through several purge cycles without requiring the technician’s participation.

Tire VacuumedWhile inflating tires with nitrogen never results in 100% purity, most nitrogen service equipment providers advise that reaching at least a 93% to 95% purity is necessary to receive the desired benefits. This ratio is normally achieved by initially purging the tires of existing air (down to just a few psi) and then refilling them with nitrogen. The purge/fill cycle is often repeated to achieve the desired level of nitrogen purity.

NOTE: Tires should never be subjected to a vacuum in an effort to eliminate the oxygen. Distorting the tire as shown in the accompanying picture can be as detrimental to the internal structure of the tire as running over potholes and road hazards.



So what should drivers do?

Overall, inflating tires with nitrogen won't hurt them and may provide some minimal benefits.

Is it worth it? If you go someplace that provides free nitrogen with new tires, why not? Additionally we’ve seen some service providers offering reasonable prices of about $5 per tire (including periodic adjustments for the life of the tire) to a less reasonable $10 per tire (with additional costs for subsequent pressure adjustments) or more as part of a service contract, which we believe exceeds the value of nitrogen’s benefit.

Rather than pay extra for nitrogen, most drivers would be better off buying an accurate tire pressure gauge and checking and adjusting their tire pressures regularly
Old 06-03-14, 08:49 AM
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Originally Posted by 2008M3
Those inexpensive air compressors won't get you a digital readout of the air pressure so you will never get it exact.

Where can we get a inexpensive air compressor with a digital read out?
I bought mine at Costco on sale a few years ago. Plugs into wall socket, not cigar lighter, but reads 2 pounds light, so I just pump 2 pounds heavier than the analog gauge. I found the digital gauges read up to 1 pound difference between different gauges of the same brand and model, so it is a real crap shoot. I go by the dash board reading when setting my pressure as that is what I will see when I scan thru the settings.
Old 06-03-14, 10:01 AM
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Originally Posted by dwlink
1. N2 molecules are larger in volume than O2 molecules so if you have a poor habit of topping up the air pressure in your tires then N2 is the way to go as your tires will bleed pressure slightly slower over time



Logic fail.

And to further my original statement: http://www.getnitrogen.org/pdf/graham.pdf

Quiz: From the paper above, describe the differences in the electron configuration of O2 and N2 molecules. Why does this result in N2 having a larger average molecular diameter?
Learned something new, thanks! Answer: because O2 has a greater amount of protons, causing the electron cloud to 'orbit' closer to center. O has 8 protons and N has 7 protons.
Old 06-03-14, 10:29 AM
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Originally Posted by 2008M3
Those inexpensive air compressors won't get you a digital readout of the air pressure so you will never get it exact.

Where can we get a inexpensive air compressor with a digital read out?
Canadian Tire has them. Bought one about a month ago, $69.99 + HST.

Mine has a digital read-out with an auto shut-off at user set pressures.
I don't trust it.
I'll over inflate 4-5 lbs. + adjust by bleeding off air & checking with my trusty mechanical gauge.
Old 06-03-14, 10:44 AM
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Originally Posted by jfelbab
This is a fallacy. Both Nitrogen and air, which is 78% Nitrogen BTW, react identically to temperature changes. It a physics gas law thing. (Gas laws - Wikipedia, the free encyclopedia)

Way too many people still believe this myth.

Good read:
http://www.tirerack.com/tires/tirete...jsp?techid=191
Those people include EVERYONE in NASCAR; we always use Nitrogen in tires so when we go down a pound in the RR, we know it will stay that way, hey, and it works,,,,,!!!!!!!
Old 06-03-14, 11:02 AM
  #22  
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Originally Posted by dctex99
Those people include EVERYONE in NASCAR; we always use Nitrogen in tires so when we go down a pound in the RR, we know it will stay that way, hey, and it works,,,,,!!!!!!!
Laws of physics are, well, laws of physics. NASCAR uses nitrogen for different reasons than you seem to opine. You never heard NASCAR teams talk about starting off with low tire pressure and as the tires heat up the tire pressure increases? NASCAR uses Nitrogen for basically two reasons. It is a dry gas that contains no moisture and unlike air (O2) doesn't support combustion.

If the temperature changes and the number of gas molecules are kept constant, then either pressure or volume (or both) will change in direct proportion to the temperature. Look it up. It is how all gases act.

"Nitrogen is a gas and is still affected by changes in ambient temperature (about one psi for every 10° Fahrenheit). Nitrogen filled tires will require pressure be added during the fall/winter months as ambient temperatures and tire pressures drop. Nitrogen is good but can't change the laws of physics."

Last edited by jfelbab; 06-03-14 at 11:12 AM.
Old 06-03-14, 11:03 AM
  #23  
vartig
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Thanks for your all replies. I just called my Lexus dealer & guess what?
They are checking the Tires pressure + wash the car for free!
hey guys another reason to love Lexus again

but I learn many things from you & still learning...
Thanks again
Old 06-07-14, 07:06 PM
  #24  
GRPFAN
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I have nitrogen in my '12 tires and I feel they will help in this case........

When I had my 2000 RX300 for 8 years or so, I had a hard time keeping air in my tires.

With age do to aluminum rim oxidation around the "bead" created a small leak in each tire.

I couldn't keep air in the tires.

Took it to the tire place I bought the tires from and they dismounted
each tire, they used a seal around the bead and filed the oxidation off the rims @ $20.00 a tire.
It help but still leaked more then I'd like.

Bottom line, I think nitrogen with less water in my tires will help over time if you plan to keep your Lexus for 10-12 years.
Old 06-08-14, 08:56 AM
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elba123
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Originally Posted by 2thfxr
I go by the dash board reading when setting my pressure as that is what I will see when I scan thru the settings.
What is the menu navigation sequence to see the pressure on each of the tires?
Old 06-09-14, 06:53 AM
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2thfxr
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Originally Posted by elba123
What is the menu navigation sequence to see the pressure on each of the tires?
I had my snow tires removed which are on separate wheels and the summer tires installed. The dealer overinflated the tires to 36 psi. The next morning I bleed out one tire at a time and wrote down the location of the tire on the dash monitor. I have had problems in the past, 2 times, had to go back as the spare tire was not registered, so now I advise the service writer to make sure the spare is registered. I keep the spare overinflated to 36 psi, as I do not want to have to go thru the bother of having to remove all the covers over the spare to maintain the spare at 33 psi everytime the temperature changes in the spring and fall.
Old 06-16-14, 02:18 AM
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Originally Posted by 2thfxr
I had my snow tires removed which are on separate wheels and the summer tires installed. The dealer overinflated the tires to 36 psi. The next morning I bleed out one tire at a time and wrote down the location of the tire on the dash monitor. I have had problems in the past, 2 times, had to go back as the spare tire was not registered, so now I advise the service writer to make sure the spare is registered. I keep the spare overinflated to 36 psi, as I do not want to have to go thru the bother of having to remove all the covers over the spare to maintain the spare at 33 psi everytime the temperature changes in the spring and fall.
OK.

Please share with us what is the menu navigation sequence to see the pressure on each of the tires. Also do you have a RX350 or 450 or some other model?

Last edited by elba123; 06-16-14 at 02:26 AM.
Old 06-23-14, 08:08 AM
  #28  
2thfxr
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I turn on the ignition so the information panel is on, I select the tire pressure info so it is on the screen, leave it on, lower the driver side window so it is easier to see the screen from outside the car. There are 4 pressures listed on my 2011 RX 450h and 5 pressures on my 2007 LS. Then I adjust 1 tire at a time either up or down, and observe which pressure setting changes on the screen and I write it down and repeat until I have written down all the tires in the order they are listed on the screen. I save this in my glove box so I can refer to it if a single tire pressure needs to be adjusted, I then know which one to adjust.
Old 06-23-14, 07:26 PM
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Gene01
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2thfxr - do you need to adjust your list when you rotate the tires?
Old 06-30-14, 06:49 AM
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I do not ever rotate tires as I have snow tires mounted on their own wheels and that is when I would be rotating tires. I would think that the tire would stay in the same location on the readout independent of its new position, I think that the readout is dependent on the order that the tire is scanned not on body location, but that is my guess.


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