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What's the problem with tire pressure?

This is from the nitrogen institute it is a direct quote

Ambient air contains about 21% oxygen. Oxygen?s smaller molecular size allows it to permeate through the rubber of the tire. By inflating with nitrogen, which is much less permeable than oxygen, the pressure changes due to oxygen loss are greatly reduced.
I love it when motorcyclists talk science or at least what they believe is science. :scratch Molecular size of molecules in a gas is pretty damn small. The difference in size between O2 and N2 means practically nothing. Actually Nitrogen's mass is less than Oxygen so it is probably smaller, depends a bit on the size of electron orbits and nucleus components. Both are made up of a whole lot of space. The only thing in this entire discussion that has any merit is IMO the amount of a water vapor in the tire. For the average rider, you are better off just measuring the "air" pressure in your tire and adjusting it in whichever brand of voodoo you subscribe to. ;)
 
I love it when motorcyclists talk science or at least what they believe is science. :scratch Molecular size of molecules in a gas is pretty damn small. The difference in size between O2 and N2 means practically nothing. Actually Nitrogen's mass is less than Oxygen so it is probably smaller, depends a bit on the size of electron orbits and nucleus components. Both are made up of a whole lot of space. The only thing in this entire discussion that has any merit is IMO the amount of a water vapor in the tire. For the average rider, you are better off just measuring the "air" pressure in your tire and adjusting it in whichever brand of voodoo you subscribe to. ;)

Please see the following link to see the entire explanation

http://www.getnitrogen.org/pdf/graham.pdf

I'll give you the basic here.

"O2 "permeates" approximately 3-4 times faster than does N2 through a typical rubber, as is used in tires, primarily because O2 has a slightly smaller effective molecular size than does N2."

I try to take advantage of every technological breakthrough. I'm putting my life on two tires with very small contact areas. I'll make use of anything that will increase my safety and the safety of my passenger. It's also why I've chosen to ride a BMW, safety, desgn,technology etc rule.
 
I love it when motorcyclists talk science or at least what they believe is science. :scratch Molecular size of molecules in a gas is pretty damn small. The difference in size between O2 and N2 means practically nothing. Actually Nitrogen's mass is less than Oxygen so it is probably smaller, depends a bit on the size of electron orbits and nucleus components. Both are made up of a whole lot of space. The only thing in this entire discussion that has any merit is IMO the amount of a water vapor in the tire. For the average rider, you are better off just measuring the "air" pressure in your tire and adjusting it in whichever brand of voodoo you subscribe to. ;)

Please see the following link to see the entire explanation

http://www.getnitrogen.org/pdf/graham.pdf

I'll give you the basic here.

"O2 "permeates" approximately 3-4 times faster than does N2 through a typical rubber, as is used in tires, primarily because O2 has a slightly smaller effective molecular size than does N2."

I try to take advantage of every technological breakthrough. I'm putting my life on two tires with very small contact areas. I'll make use of anything that will increase my safety and the safety of my passenger. It's also why I've chosen to ride a BMW, safety, desgn,technology etc rule.
 
Define science and who has exclusive membership to that club.

"I love it when motorcyclists talk science or at least what they believe is science. Molecular size "
It struck me as odd, this quote as I am aware of a couple of scientist who ride bmw's or did. On Montesano mountain in Huntsville AL, I'm told that Verner Von Braun's widow still lives in the house that her late husband owned when he was "liberated" from Nazi Germany to work on the rocket program that put a man on the moon. I've been told that in the house's garage is the BMW with sidecar that they road all over Huntsville and Tennessee in the 40's 50's and 60's.
I remember going into Northrop Grumann's headquarters in California when I worked on the RAH 66 Comanche project and walking down the many long hallways with doors leading to project offices, I saw a poster on the wall near the door of one of these offices that read, "yes we are rocket scientists!" I guess that takes all excuses off the table.
Moreover, I suspect the real question would be, If a scientist did ride BMW motorcycles and was a BMW MOA member, what would possibly motivate him to pursue the litany of diatribe that flows down the threads of this forum like the 'salmon of Capastrano'?
 
Please see the following link to see the entire explanation

http://www.getnitrogen.org/pdf/graham.pdf

I'll give you the basic here.

"O2 "permeates" approximately 3-4 times faster than does N2 through a typical rubber, as is used in tires, primarily because O2 has a slightly smaller effective molecular size than does N2."

I try to take advantage of every technological breakthrough. I'm putting my life on two tires with very small contact areas. I'll make use of anything that will increase my safety and the safety of my passenger. It's also why I've chosen to ride a BMW, safety, desgn,technology etc rule.
This guy says that Grahams Law of "Diffusion" which is what it was taught as in my HS and college chem classes is wrong. If it wasn't for that law Oak Ridge wouldn't have pumped out weapons grade uranium for nukes back in the last disagreement we had with the Rising Sun crowd. Grahams Law depends on molecular weight. Now size is in the eye of the beholder. Most and I mean by a bunch of the molecule, any molecule is just space. Why O2 goes through rubber faster than N2, I would bet has more to do with the electron configuration of O2 and N2 as compared to the long chain molecules of rubber than it does with pushing a molecule through gaps in other molecules. The term effective size was thrown out. Now there is a totally nebulous statement. The effective size of any molecule would depend on what was around it, that is what kind of van der Waals forces could be generated between the molecules, what kind of loose bonding could be formed between electron pairs and empty shells, etc, etc.

Yes there very well may be a couple "scientist" who ride motorcycles. Maybe Einstein tried to jump the Grand Canyon before Evil. Bottom line is your average motorcycle rider isn't up for a Nobel Prize. Scientists probably rank in the statistically insignificant category along with most other specific classifications.
 
I'm confused. If gonzo49 wanted to run piss in his tires why would it matter to chewbacca? Is Gonzo49 going to deplete the naturally occurring nitrogen levels in ambient air by using it straight in his tires? Is chewbacca a N2 salesman and trying to hustle gonzo49 and the forum into using straight air in order to corner the market on N2 sales. Is Chebacca planning on riding two up with gonzo49 soon and now has a genuine concern for his welfare and safety on those nitrogen laced tires? The drama is confusing me as I thought this was a MOA forum of MOA members that see each other periodically from time to time...rally to rally, and come here to share ideas, ponder, seek information without fear of rebuke or ridicule, as most of us aren't scientist, just riders seeking information, which is kind of a science in a way. Use all that nitrogen up in your tires, the less n2 in the atmosphere the better, bends are bad for x-navy diver types. Maybe we should use helium in our tires like a saturation diver.
 

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It's always interesting to see reference to "newer, higher pressure tires."

Correct me if I'm wrong, but in most cases this is the difference between radial and bias-ply tires.

In most cases, the tire specified for your bike is one or the other but never both. If that's the case, there simply aren't "newer, higher pressure tires" applicable to your bike.

(One exception may be Conti's new radials directed towards Airheads and maybe old Ks, but haven't studied that. They have just been introduced this summer.)

And, the numbers on the sidewall are completely meaningless except that they indicate the maximum pressure safe to use in this tire. This has NOTHING to do with BMW's or the tire manufacturer's recommended pressure for your particular bike and load conditions.

Except for the following, that is ... A recent presentation at our dealer by a Metzeler tire rep featured the notion that if your goal is to maximize tire mileage, i.e. tread life, then you should indeed run your tires at the maximum pressure indicated on the sidewall. It's printed a little less strongly in Metzeler brochures, too. This of course, is NEVER the basis for BMW's pressure recommendations for your bike and most obviously may involve some handling and/or comfort and/or performance compromises. I'm not doing it, as my goal is fun associated with riding and for sure not carefully saving every penny and diminishing the fun. I mean, if it's about only tread life, just never ride.

If you've a current model BMW, recommended tires by brand are listed at BMW's website. These charts don't go very far back as regards discontinued models IIRC. There is, not completely coincidentally, sometimes not sizes for older bikes in the latest/greatest tire models, and the older bike guys then use the older models anyway. The notion that perhaps tires (brands) not on the recommended list somehow require completely different pressures is a bit of stretch in logic, too, I think. Look for that brand to publish something instead.

Bottom line, I think, is that BMW's recommendations are simply fine and are good for a long time. If a tire manufacturer will publish in writing or on its web page that they indeed have different recommendations for you, then pay attention. There's not a lot of data provided by various internet contributors to back up their claims when it comes to varying from BMW specifications, and they should direct you to data rather than their opinions and unscientific observations. I know for sure that I've never seen specifically published by a tire manufacturer that pressures recommended by BMW in, say, the 1990s or 80s or 70s have been superceded by "new technology." I'd love to be directed to it.

You can also rationalize that somehow BMW's specifications don't apply specifically to you because you must weigh something different than their average rider or something like that, but I'd instead conclude their figures can be recognized as covering normal variations. BMW's figures are quite fine and it's not really about demonstrating that you know more than they do, is it? When it comes to "voice of experience," nobody tops BMW.

Not often that my universe and that of Kent's align, but IMHO, his comments are spot on and we would be better riders to objectively consider his summation.

+1 ! :thumb
 
It's always interesting to see reference to "newer, higher pressure tires."

Correct me if I'm wrong, but in most cases this is the difference between radial and bias-ply tires.

.

There is one other difference. "Newer, higher pressure" tires are very often those with a lower aspect ratio. Tires in a /55 or/50 configuration are usually run at higher pressures.
 
Yet another classic case of asking for the time and being told how to build a watch! :rofl

Dear Sir -

No one appreciates a sarcastic cliche more than I do - often employed.

However, BMW is somewhat ambivalent to the passage of time when it comes to glitches.

It was 'time' already back in 2005 to re-engineer the FD to prevent way too many failures - failures that continue to this day in too great of numbers, despite some token tweaking.

It was 'time' for years now to stop trying to promote a fuel measuring system (strip) with the sophistication of the space shuttle, and prioritize reliability.

It was 'time' long ago for them to design headlamps to be owner friendly for access to changing bulbs.

Fuel pump fittings/cracks, windshield struts (upper & lower), center stand bolt retention, etc. - the list is a tad long for a marque still touted as "uber-reliable."

What time is it? For God's sake, don't ask BMW. :dunno
 
Dear Sir -

No one appreciates a sarcastic cliche more than I do - often employed.

However, BMW is somewhat ambivalent to the passage of time when it comes to glitches.

It was 'time' already back in 2005 to re-engineer the FD to prevent way too many failures - failures that continue to this day in too great of numbers, despite some token tweaking.

It was 'time' for years now to stop trying to promote a fuel measuring system (strip) with the sophistication of the space shuttle, and prioritize reliability.

It was 'time' long ago for them to design headlamps to be owner friendly for access to changing bulbs.

Fuel pump fittings/cracks, windshield struts (upper & lower), center stand bolt retention, etc. - the list is a tad long for a marque still touted as "uber-reliable."

What time is it? For God's sake, don't ask BMW. :dunno

What time is it? Maybe it's time to ride a Honda!:eek

pete
2011 R1200RT
Be yourself. Everyone else is already taken." - Oscar Wilde
 
Time for everything

What time is it? Maybe it's time to ride a Honda!:eek

When it came time to replace the 1989 Gold Wing that served me well for 23 years and 260,000 miles, I figured that another Honda would be the most practical decision. Oh, I had a few problems in a quarter million miles. A u-joint went bad and took the drive shaft with it; that cost me about $800. The alternator rotor burned out ($200) and the brushes needed replacement every 50,000 miles (easy DIY with $4 brushes). Oh yeah, new steering stem bearings every 100K. I probably spent around $2,500 in repair bills while I owned the bike. That works out to about $100 per year. Pretty good, huh?

So what is the downside? Most mechanics told me that they wouldn't work on a Honda older than 10 years. Even when they would work on it, the mechanic would often say "I hate Gold Wings" to my face. When I needed a real mechanic for a carburetor problem, the dealers refused to work on such an old bike. The carb problem made the bike impossible to ride and forced me to junk it.

My BMW dealer experience has been much better.

Pertaining to the bikes themselves, I never expected my 2005 R1200RT to be as reliable as a Honda. The Wing was big and beefy with thick steel parts while the Beemer has slender aluminum pieces. It also weighs 300 pounds less and makes more horsepower. It holds a steady line in a high speed sweeper and is stable in a bumpy curve. The Honda wallowed and pitched when I asked it to turn faster than a Cadillac.

My "time for a Honda" is past. I'll never say anything bad about the bikes because they did right by me. The dealers are another story. Maybe you have to trade weight for reliability. If that is true, then BMW and Honda will each have an advantage. I had a long relationship with a comfortable and reliable machine. Now I am enjoying a fling with a hot svelte number.

Maybe it is just my reaction to a midlife crisis? ;-)
 
Thanks for sharing your experience Bruce.

Every bike is a compromise. There is no perfect one made.

Read the other bike's forums and you will see what problems that make/model have. You would never buy a motorcycle if your decision was solely based on forums.

Are there FD problems? Some folks have experienced them. For them it has sometimes been an expensive/frustrating experience.

And that can be said for any other problem with BMWs.

Is your bike likely to suffer from a failed FD, odds are no.


The only thing we know with certainty is the first year of any model will uncover something that could be improved.

But then again, I'm the guy with 2 R 1100 RT's so what the heck do I know?:dance
 
Dear Sir -

No one appreciates a sarcastic cliche more than I do - often employed.

However, BMW is somewhat ambivalent to the passage of time when it comes to glitches.

It was 'time' already back in 2005 to re-engineer the FD to prevent way too many failures - failures that continue to this day in too great of numbers, despite some token tweaking.

It was 'time' for years now to stop trying to promote a fuel measuring system (strip) with the sophistication of the space shuttle, and prioritize reliability.

It was 'time' long ago for them to design headlamps to be owner friendly for access to changing bulbs.

Fuel pump fittings/cracks, windshield struts (upper & lower), center stand bolt retention, etc. - the list is a tad long for a marque still touted as "uber-reliable."

What time is it? For God's sake, don't ask BMW. :dunno

For many, myself included, the days of "uber-reliable" BMW's is long gone based on those and many other problems.

In trying to think about it from BMW's POV, I can only guess that there is not a financial motive to do any of the above. After all, they are selling record number of bikes year after year.

Perhaps the Airheads have it right? "Simple by choice."
 
Now back to the original OP.

After a lot of posts which include a lot of information and differing opinions, only one thing is certain.

You have to check the pressure in your tires, regardless of the makeup of the gasses that are inside them. :D
 
There is one other difference. "Newer, higher pressure" tires are very often those with a lower aspect ratio. Tires in a /55 or/50 configuration are usually run at higher pressures.

Yes, and most are radials. And you really shouldn't put a lower profile tire on a bike designed for a higher profile tire.
 
Pertaining to the bikes themselves, I never expected my 2005 R1200RT to be as reliable as a Honda.

Now there's realistic and accurate understanding of things automotive!

Guys buying Porsches and Ferraris don't get Camry reliability either.

BMW as well is not in the Camry business.

Amazing how many BMW owners don't get this.

Your entire post was intelligent and refreshing.

PS: don't think there's much guilt associated with Porsche or Ferrari purchase and think that's exactly the case with lots of BMW complaints, i.e. buyer remorse over having such a great toy. It's cost of doing business, don't worry, be happy.

PPS: set tire pressure according to the sticker
 
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