Tire Pressure

[Clint]

You could have run 60 lbs. and been "fine". Doesn't make it right. Your contact patch is smaller than it should be. The tire's ability to absorb bumps and road imperfections is compromised, and the bike's suspension won't work as it was designed.

But, to each his own.

[Copronymous]

Rowdy is right on regarding this. Take this analogy:

The Ford Explorer (several years worth of models anyway) used tires whose max PSI was rated at 35 PSI. What ford found was that if you ran tires at 35 PSI on an Explorer, they became unstable and statistically more apt to roll over.

Citing that, Ford Motor Company's engineers tested and tested, until they found the optimal safe tire pressure: 26 PSI.

Who do I know this? I worked for Ford. But still, it's common in many manufacturers.

I disagree on "To each his own". Improperly inflated tires can lead to problems. These problems don't usually occur in "normal" (or safe) conditions. These problems will crop up when you don't want them to, like hard cornering, accident avoidance, etc.

The proper pressure is listed on the bike and in the manual. Ignore what the tire reads completely.

[Easy Rider]

Originally Posted by Powerslave

I have no problems with it, so I will continue to use around 40PSi in both tires, suits me fine,

Don't confuse me with facts; my mind is made up!

Get back to us after another few thousand miles and let us know about how your tires are wearing. I think someone in an earlier message said that excessive pressure would cause them to wear a strip down the middle.

[palanon]

I don't know what the big deal is. I just fill my tires with Air-Crete and never worry about it again.

It gives you a nice stiff ride too.

[Powerslave]

Funny how some of you are preaching the gospel of tire inflation, like it's your problem, and not just mine, yes JUST MINE. Heed the word of someone who thinks they know it all? I think NOT... Well, if it makes you happy to preach, then by all means, go ahead, but I will be the infidel to whatever you are preaching.

So, how many K miles will it take to be wrong, huh? I want an exact figure, since you know it all, on how many miles I will wish I had laid down before your great powers of air pressure.

See, 'Cause I got more than a few K miles, even more than 5k miles, heck, even more than 6k! Guess what? The tires are fine. Amazing now normal people turn into preachers because THEY think something is wrong? Well, again, to each his own, and the bike CORNERS LIKE A DREAM!!! No, I am awake when I do it, so it's quite fine. In any case, hmm, I will have to buy a new, umm, tire? Wow, what a shame.

You really believe that 36 and 40 are WAY off base? Yeah, I can see the trigonometry majors are completely boggled over it.

[Clint]

Hey, no one appreciates your stubborn dissent more than I do. The problem is, you haven't offered a good reason. "Because I felt like it" doesn't get you far. Seems to me there isn't much difference between you expressing your position and me mine, except I have sound reasoning.

You have every right to do your own thing, but if you want to convince anyone you're right, throw us a bone.

[Powerslave]

Yes father, forgive me, for I have sinned; my tire pressure is 40Psi and not 36, bless me, BLESS me...

[palanon]

[Powerslave]

Hey Palanon, How does that Aircrete work in a tire? I know they use it for building homes now, making blocks; to make them more efficient (hot aircrete). They use steel reinforced aircrete flooring elements too.

I am not sure how you get a finished product in there, due to how Aircrete is formed:

The essential raw materials used to make aircrete are lime, sand of Quartz, and water. In most cases there will also be cement, Gypsum, or Anhydrite, and sometimes, as a substitution to Quartz, fly ash (highly toxic) and ground metallurgy slag. These latest ones and the Quartz sand provide silicium dioxide (silica) for the formation of Tobermorite. Calciumoxide is given by the lime. If there will be used cement too, then by this way both calcium oxide and silicium dioxide will be put into the mixture. So, all together with water, the main raw materials to produce aircrete are provided.

How are the many many pores put inside of this construction material? Well, it is quite similar to baking a cake. As gas forming agent aluminum powder or paste is taken. The very tiny aluminum flakes produce a lot of small bubbles of Hydrogen in the slurry of the raw material mixture. This way the mixture rises in its molds until all aluminum has reacted and the desired volume is reached. You need only a very small amount of aluminum powder.

The bubbles formed are mostly about 1 mm in diameter. Hydrogen is a very volatile gas, so it is replaced rapidly by air. Inside a tire, I don't see it working.

The mixture gets hard soon after expanding process has ended. It also increases in temperature up to over 80°C. After a certain time of setting the material is hard enough to be cut into pieces of desired format. A machine with wires arranged at certain distances makes this step of production process.

Leaving the material at room temperature, and in air would not result in sufficient strength, it is necessary to cure the material in saturated steam at high pressure. This last step in process of producing aircrete has to be done in autoclaves at 180 to 200°C. After some hours aircrete is finished. All the calcium oxide for the formation of Tobermorite is consumed, only a residual of silicium dioxide remains and can be found as small grains of Quartz.

So, how are you getting that, in your tires?

[mrimpala]

Can't we all just get along?!

If Powerslave wants to put 40 psi in, so be it. Powerslave, they were just trying to help, and give you some safety advice. Don't wanna take it, don't. No biggie. I had 40 psi in my tires when I got it from the dealer. Dropped it down to a hair over what the bike says to use, and have been happy. Do what you gotta do, just Ride Safe.

[HITEST]

Anyone running nitrogen in their tires? I'm not asking if its ok or anything, just curious.. I know two friends that do...

[Clint]

*snicker*

I'd love to hear their reasons.

[Copronymous]

Originally Posted by RowdyRed94

*snicker*

I'd love to hear their reasons.

I've been told it's for 2 reasons (take them for what they're worth):

1. Nitrogen molecules themselves are larger, so the bleed out slower, and
2. Nitrogen is less a less volatile gas than O2.

I get my truck tires at Costco, and that's what they use so I let them. At home I have my own compressor, so I just use air .

[Clint]

Yup. You can ignore basic bike maintenance for 9 months instead of three before you notice that your tires are flat, and 2) air is 80% nitrogen already. Unless you're planning on lighting your tires on fire, it's a moot point.

Just my $.02.

[Uncle B]

Strange New Products: Nitrogen-Filled Tires for the People

[Powerslave]

They did studies on Nitrogen in tires, and it's not worth it. The air we breathe is already 20% oxygen, 0.038% carbon dioxide, and the rest NITROGEN (about 80%), so what's another 20% to make it pure nitrogen? It's nothing...

SO, I just put 40Lbs of regular 20/80 air in my tires, that have about 6K miles on them, and are showing EVEN tread ware. I had the tires checked (gaged) after this stupid pressure discussion, and I am fine, I mean, the TIRES are fine.

[skynyrd fan]

So even though I know its 29 and 36, my Perellis are supposed to be at 40 pounds max. Am I wrong to run them that high? So should I be running them at whats on the bike frame? Thank you.

[Clint]

Did you read the thread?

[Easy Rider]

Originally Posted by skynyrd fan

So even though I know its 29 and 36, my Perellis are supposed to be at 40 pounds max. Am I wrong to run them that high? So should I be running them at whats on the bike frame? Thank you.

Sigh!

That is EXACTLY where this discussion started.
Like Rowdy said, did you read the whole thread?
If not, you should.

So to recap:

Most people in most situations should use the pressures on the frame sticker or in the owners manual. The Max. pressure on the tire will (almost) always be higher. Most people should not be at the max. pressure because the load placed on the tires does not require the max. pressure.

Those who feel a need to deviate from the recommended pressures are certainly free to do so..........they should just try to refrain from preaching that it is the right thing to do..........especially without any supporting reasons.

The difference between 35 and 40 isn't that much but what are you gonna do if the next set of tires you get has a max. pressure of 50 ???

Here's an extreme example. I got new tires for my pickup. It never carries a heavy load but I got "real" 4 ply tires just for an extra margin of safety. The max. pressure listed on the sidewall is 60 PSI. Do you think I actually run them at 60 psi? Of course I don't, when the sticker says 30 for a minimal load and 45 for a full load. I run them at 35, knowing that I need to air them up if I'm going to be hauling a load of rock.

[Cappu]

I'm a little surprised no one mentioned going to the tire manufacturer's websites to check what their engineers recommend. The tire brand mounted by the motorcycle producer should be considered OEM and run at the "sticker pressure," but I'm going to ride with the Avon engineer's suggestion in my Venom skins.