Check this out tire psi (http://www.snort4x4.com/cgi-bin/YabbGold/YaBB.pl/YaBB.pl?board=Topic;action=display;num=1043469073)

How about pasting that into the actual link, so clicky works? ;)

hahaha.. gotta love a good argument.
Scott

Duh! It's all about the physics. Ever hear the phrase "Lighter than air"? Meaning air has weight. So if you have more of it, in this case compressing it into a tire, it's going to weigh more.

I don't think weight is that much of a concern for the average trail rig. I mean... look at what we normally carry. The one thing I do to cut down on the weight is only keep 2-4psi of air in the spare if that much. By not running 20-30 psi, thats 16-26lbs off the rig.



You have gotta be kidding..... How the hell did this guy manage to build a rig?

Originally posted by mikrosilakhan




You have gotta be kidding..... How the hell did this guy manage to build a rig?

Exactly! Any intelligent human being knows you have to multiply that 16-26psi times 5 for a total weight savings of 80-130 pounds!:flipoff2:

Holy shiat that is just too damn funny!!

Besides this line By not running 20-30 psi, thats 16-26lbs off the rig. he has it right. Air does have weight. It is all of the weight of the atmosphere is what is pushing against me at about 14.7 psi right now (I am at sea level).

No Fawking way!!! Is this guy even have a brain? Please tell me this is one of you guys Fawking around on another board!!!! :eek:

Read the whole thing and how he justifys the math behind his "logic" later on in the topic.

I'm not reading that whole thread, but remember this:
Air has weight by volume
The increase in volume of air to go from 10psi to 30psi in a tire is minimal
Therefore, the increase in weight due to tire pressure is minimal.

:flipoff2:

Damn I'm hooking my spare up to a vaccuum cleaner!

Originally posted by Belly Dragger
Damn I'm hooking my dick up to a vaccuum cleaner!

:eek: :eek: TMI, perv!!!!!

:D

Originally posted by TonyN
:eek: :eek: TMI, perv!!!!!:laughing: :laughing: :laughing:

Originally posted by TonyN


:eek: :eek: TMI, perv!!!!!

:D

Ahhhh NOW that picture make SOOOOO much more sense BD!!:eek: :D

Originally posted on Snort by Travis on: Jan 24th, 2003, 7:42pm

*The one thing I do to cut down on the weight is only keep 2-4psi of air in the spare if that much. *By not running 20-30 psi, thats 16-26lbs off the rig.

I laughed so hard I exhaled completely and lost 10 lbs. :D

There was actually ONE shred of factual data there:

1.18 GRAMS in a liter of air

So, if it takes 100 liters to fill your tire to 35 PSI (for instance), it would increase the weight of the tire by 118 grams, or 4.16 ounces. That's right, a quarter of a pound. And 100 liters of air is a LOT of air!

Air does weigh something, and his 20 lbs guess is absurd, something along the lines of <1 lb would be closer...

A 35x12.50r15 tire has something close to a volume of 120 liters...

Going from 0 psig(14.7psia) to 28 psig(42.7psia) is roughly tripling(2.9) the pressure in the tire. Assuming his calculation or should I say someone on the net(look
here (http://www.sciencenet.org.uk/database/Physics/9701/p00529d.html) is correct, a litre weighs 1.22g. So 2.9 *
1.22g/L * 120 L= 424g divided by 454g/lb = .93LBS

EDIT:
forgot to subtract original volume of air, so it would be:
120L * 1.22g / 454g/lb= .32lbs

.93lbs -.32lbs= .61lbs

Brett, why don't you post that in the other board?

But then again, i guess the topic is providing some amusement.
:D

I tried to post it but I am not registered...

-Brett

Thank god, I thought that you fools were trying to say that a filled tire would NOT weigh more than an empty tire, I was gonna bitch slap all of ya!

I mean, look at scuba, you have a full tank, it's really heavy, you sink to the bottom. After a while, you get rid of some of that air, the tank gets lighter, you float back to the surface. Isn't that how diving works? :flipoff2:

Originally posted by Pazuzu

I mean, look at scuba, you have a full tank, it's really heavy, you sink to the bottom. After a while, you get rid of some of that air, the tank gets lighter, you float back to the surface. Isn't that how diving works? :flipoff2:

Stick to stars and chit dude. :flipoff2:

Everybody please donate money to my new fundraiser.

Send cash only to the:

Sterilze Travis So He Can't Reproduce Fund
P.O. Box 99
Head up your ass, 99534

We can't let this guy reproduce.

air weighs about 7.5 lbs per 100cf. helium only weighs 1 lb per 100 cf.

A liter of air weighs 1.2 grams. If you want to figure all this out for yourself, here's a little explanation and formula:

The atomic weights of nitrogen and oxygen are 14 and 16, respectively.

But since what is in air is not free atoms, but atoms bound in pairs,

the _molecular_ weights of N_2 and O_2 are 28 and 32, respectively. To

get the average molecular weight of air, then we figure out the weighted

average like so:



70% x 28 + 30% x 32 = 0.7 x 28 + 0.3 x 32 = 19.6 + 9.6 = 29.2

:flipoff2:

(I'd like to believe I figured this out myself :D NOPE!:flipoff2: )

i was bored and i came up with 2.28 lb weight savings by having 0 psi vs 30psi in a 38x14.5 tire with a 14x10 rim, these calcs are not great because a.) I was too lazy to do some things myself and b.) my L to ci was 5.7 L=350ci based on chevy advertising. Definately not signifigant but a savings nonetheless

Normal air follows the following calculation:

mass of air=m=1.17 g/atm for a volume of 1 liter, temp of 300K (80 degrees F).

So, for a tire with 1 atm of air (0psi) and a volume of 170 liters (approx for a 36x12.5x15 tire), you get:

m1=1.17(170)(1)=198.9 grams.
For the same tire, with 29.4psi (3 atm), you get a mass of m2=1.17(170)(3)=596.7grams

Difference? Delta-m=596.7-198.9=397.8~400 grams, which is 0.88 pounds.

I think the main problem calculating this is "what is the internal volume of the tire, when aired up and at 0psi?"

Originally posted by Al Kaholick
L to ci was 5.7 L=350ci

You need to learn about the "convert anything" web site:

Convert anything (http://www.onlineconversion.com/)

Originally posted by Bobzooki


You need to learn about the "convert anything" web site:

Convert anything (http://www.onlineconversion.com/)

beutiful that will be nice for physics and stuff

you all do realize that this is the same Travis Walder from this board don't you?

Since we are all on this weight savings thread, I've just switched my motor oil from 20w50 to a lighter 5w30.

I figure since my Land Criser takes 8 Qts, I'm saving roughly 67.825 pounds.
Just in the weight savings alone, I'm getting
4-12 mpg better.:flipoff2: :flipoff2:

Here, in Los Angeles, are air is a little heavier.

Originally posted by JR
Here, in Los Angeles, are air is a little heavier.

I'll attest to that. Sure makes my lungs rebel at the first breath

Don't you have days where it feels like the weight of the earth's atmosphere is on your shoulders?

Originally posted by landuseorc
A liter of air weighs 1.2 grams. If you want to figure all this out for yourself, here's a little explanation and formula:

The atomic weights of nitrogen and oxygen are 14 and 16, respectively.

But since what is in air is not free atoms, but atoms bound in pairs,

the _molecular_ weights of N_2 and O_2 are 28 and 32, respectively. To

get the average molecular weight of air, then we figure out the weighted

average like so:



70% x 28 + 30% x 32 = 0.7 x 28 + 0.3 x 32 = 19.6 + 9.6 = 29.2

:flipoff2:

(I'd like to believe I figured this out myself :D NOPE!:flipoff2: )

since when does air have 30% oxygen in it? how about 20.94%. :rolleyes:

This thread is so funny I had to bring it back from the dead.:laughing:

Damn I'm hooking my spare up to a vaccuum cleaner!

:laughing::laughing::laughing:

Hell, I'm vacuuming ALL my tires and will run on vacuum pressure instead!

This thread is so funny I had to bring it back from the dead.:laughing:

Dude:shaking:

Besides this line he has it right. Air does have weight. It is all of the weight of the atmosphere is what is pushing against me at about 14.7 psi right now (I am at sea level).

by that argument overweight types should move to Leadville,CO which is at ~10k ft so they can live where the pressure is only 600 Torr (sea level = 760 torr=14.68 PSIA) and weigh less. :D

Gravity does have a role in weight (vs mass)... ;)

D.

Normal air follows the following calculation:

Yeah, but we're not dealing with normal air here. Oh not at all. This is special 4-wheeling air, that you can get at your local 4-Wheel Parts Warehouse. It's MUCH heavier than normal air, resulting in a lower center of gravity, and making your trail rig much more capable. 4WPW sells this radical new weapon in your off-road arsenal in 100 pound boxes, and 5 pound bags (about the size of a bag of potato chips you get from a vending machine). All the top rock-crawling competitors have been using 4WheelHeaviAir(TM) for years - it's been one of the best kept secrets in the business...until NOW. And you can get your very own 4WheeHeaviAir(TM) for your rig, from 4WPW. It runs about $50 for a rig running 33X12.50-15's at 12 psi. :smokin:

Besides this line he has it right. Air does have weight. It is all of the weight of the atmosphere is what is pushing against me at about 14.7 psi right now (I am at sea level).

Argh. This is bugging me.

Stochiometric?
Spectrometric?
Spokimetric?

God damnit, that's going to bug me. What the term for that pressure?

by that argument overweight types should move to Leadville which is at 10k ft so they can live where the pressure is only 600 Torr (sea level = 760 torr=14.68 PSIA) and weigh less. :D

Gravity does have a role in weight (vs mass)... ;)

D.

But what if the magnetic poles reverse?

Stochiometric?


Poikilothermic???

But what if the magnetic poles reverse?

:D:D then one has a "negative" mass and float away like a helium ballon. :flipoff2:

Dumb Q, Dumb answer... :D

D.

:D:D then one has a "negative" mass and float away like a helium ballon. :flipoff2:
D.

So, if one has a negative mass, does two have a positive mass again, followed by three being negative?

Or are prime numbers negative, while non-prime numbers become imaginary?

:confused:

Poikilothermic???

That's a rather cold blooded answer on a Fri... :D

D.

That's a rather cold blooded answer on a Fri... :D


Must be because I'm thinking about margaritas on the beach!!! :grinpimp:

This thread is so funny I had to bring it back from the dead.:laughing:




Stir Stir Stir... Poor Travis will never live this down will he?

So, if one has a negative mass, does two have a positive mass again, followed by three being negative?

Or are prime numbers negative, while non-prime numbers become imaginary?

:confused:

Seem to recall that when goes thru the Maxwell equasion derivation one comes up with an answer of the square root of -2 as to why this happens... :D

D.

So thats why my oxygen tank for my torches are so heavy!!!:eek:

Seem to recall that when goes thru the Maxwell equasion derivation one comes up with an answer of the square root of -2 as to why this happens... :D


Exactly. I did that one time, when I was in high school. We had driven up to Nederland, to buy blotter-acid, and somewhere in the middle of the night, they stole the moon, and replaced it with a cheap cardboard replica. I still can't believe that nobody else has noticed that!

:smokin:

Exactly. I did that one time, when I was in high school. We had driven up to Nederland, to buy blotter-acid, and somewhere in the middle of the night, they stole the moon, and replaced it with a cheap cardboard replica. I still can't believe that nobody else has noticed that!

:smokin:

Somebody headed out for vacation possibly cuz we are in rare form today... :D

D.

:D:D then one has a "negative" mass and float away like a helium ballon. :flipoff2:


D.

If that is the case, that means hummers will flip over by simply pointing it at an obstacle and samurais will become the most stable vehicle ever offroaded:confused:

Or does that mean the samurai will float away like a baloon from a parade on a windy day, and hummers will get 30 MPG?

:laughing::laughing::laughing:

Hell, I'm vacuuming ALL my tires and will run on vacuum pressure instead!

By vacuuming the tires, you'll create suction, which will increase tractive capacity.

If you're really smart, you'll figure out how to utilize manifold vacuum to give a variable tire pressure (or lack thereof) which can maximize tire suction as needed.