Does the air inside the tire spin?

Paul Kish

That's it, that's the question.

Rick Blood

First, why would you want to know?
Just as it would with water, the air initially stays still until the friction from the surfaces inside the wheel and tire cause it to eventually catch up.
I feel like I am being sucked into something here.

Rodney Ebersole

Only Paul could come up with that question. Now if we use heavier gas that would give us more momentum wouldn't it? Or go with lighter gas for more acceleration? That sounds like my wife when I need to add weight to the kart she suggests that I just put more pounds of air in the tires. Ok Paul lets see some smoke from all the wood your burning.

Todd Bolton · Joined: 18 Jul 2001 Posts: 894

Are you sure wood is the only thing Paul has burning?????

Paul Kish

I have heard that some do wind tunnel testing to see how the tire/wheel traveling thru the air can effect handling. Naturally the only "logical" next question would be, HEY,, there's air inside the tire too, how about it?

And one thing/thought lead to another so out it came. I know the faster I walk the more the air in my head effects me, there'a got to be some good information there.

And people many times ask about that dot on the tire and is there a right or wrong way to mount a tire. Have you looked inside a tire? They ain't all equal if you look at how they are built. Some are, but many have ribs, etc, that could would interfer with air flow, if there was air flow inside a tire. From that, heck maby there is a right or wrong way to mount a tire.

Or could you cause the air to rotate inside the tire with paddles or vaines of some sort on the inside of the rim? If you could get it to flow could you make it do work for you? Maby help slow the kart upon entry, who knows, I sure don't that's why i'm asking. There is much debate about top end racing verses bottom end racing and how something as simple as clutch driver size effecting things. Heck tires are things, and air does offer resistance. Maby we need to look at reducing air resistance inside the tires? Man that last sentence sounded like humor, but is it? ? ?

Paul Kish

ps.... ain't burning nothing, done got burned out years ago.

Rick Blood

The rate of acceleration of a kart tire is very slow. The wheel and tire are only rotating at about 1700 RPM . The air inside is aerodynamically isolated by the tire. There is no measurable resistance between the tire and the air. A wind tunnel has no clue as to what is inside the tire (maybe mice) it only see's the tire.
Dick Hansen at Yamaha of America once told me about a guy who added a small amount of water in each tire to control temp rise (don't do this). Someone else thought this was a cool idea so he filled the tires with water. He removed 20 lbs. of lead to compensate for the water. It accelerated about the same but would not stop until it hit a fence.
IF you could weigh the air in the tires, how much do you think it would be? You are giving air too much credit.

I'm still waiting for the punch line.

james fuchs · Joined: 22 Jul 2001 Posts: 184

in the early years of nascar racing there was a guy that fillied the rear tire with water .the guy won meany races ,one day the car broke a axel and a pit guy tryed to clear it from track,had to bring out help to lift it .the old timer said that for years thay could not fig.out how he ran that good .
jim fuchs

Oscar Aguilera · Joined: 18 Jul 2001 Posts: 1614

The thing I noticed early on about chassis tuning on forums is that it is a Philosiphy. That is why we get such philosphical questions isn't it?

Question: if you put water in a tire and the temp rose the water would evaporate and increase the tire pressure? Or the water is suppossed to keep the tire from getting hot? Please explain where the notion of putting water in a tire would be better.

What track was that train of thought on?

Chuck Bunnell

There are a couple of conflicting things here about a small amount of water in a tire. As the temperature of the air, (or whatever is inside the tire), goes up less water can be dissolved in it. If the temperature is high enough the water will become water vapor and just be another gas in there, though if it changed phase from liquid to gas there would be a pressure rise. The increase in temperature of the tire will heat the internal gas leading to pressure rise also. Meanwhile the tire is under pressure which will increase the temperature required to vaporize the water. This is taking more thought than I'm ready for at lunch! It's a very dynamic system.

Now filling a tire completely with water can do some interesting things. As was pointed out earlier, it will take some time before the water in the tire is rotating with the tire. I'm guessing it was an outside rear tire and would have additional momentum which would help rotate the car in the corner. Probably like having a lot of stagger without the drag going down the straight. Particularly if the rules don't allow rear stagger.

For what it's worth, the air is spinning around my head now!

Chuck Bunnell

There are a couple of conflicting things here about a small amount of water in a tire. As the temperature of the air, (or whatever is inside the tire), goes up less water can be dissolved in it. If the temperature is high enough the water will become water vapor and just be another gas in there, though if it changed phase from liquid to gas there would be a pressure rise. The increase in temperature of the tire will heat the internal gas leading to pressure rise also. Meanwhile the tire is under pressure which will increase the temperature required to vaporize the water. This is taking more thought than I'm ready for at lunch! It's a very dynamic system.

Now filling a tire completely with water can do some interesting things. As was pointed out earlier, it will take some time before the water in the tire is rotating with the tire. I'm guessing it was an outside rear tire and would have additional momentum which would help rotate the car in the corner. Probably like having a lot of stagger without the drag going down the straight. Particularly if the rules don't allow rear stagger.

For what it's worth, the air is spinning around my head now!

Rick Blood

Remember that the weight of the water will make the wheel act like a gyro and will not want to turn. Add to that the fact that it is unsprung weight.
I will repeat, do not try this anyplace but in your head.

james fuchs · Joined: 22 Jul 2001 Posts: 184

this was done on dirt track racing in the early days of nascar.it was to get more rear bite .this would not change the way the chassis worked just planted the tire better.,jim fuchs

Oscar Aguilera · Joined: 18 Jul 2001 Posts: 1614

Doing the thing in my head I imagine an unbalanced, too heavy to stop suddenly, so heavy it took too much time to get up to speed, over inflated tire, that is about to cook itself into the relm of "no traction".

Maybe I overworked my imagination?

I think I agree mostly with the gyro thing.

John Denman

quote:
Originally posted by Oscar Aguilera:
Doing the thing in my head I imagine an unbalanced, too heavy to stop suddenly, so heavy it took too much time to get up to speed, over inflated tire, that is about to cook itself into the relm of "no traction".

Maybe I overworked my imagination?

I think I agree mostly with the gyro thing.

Geez, it sounds like we are beginning to hedge into Quantum Mechanics here.

Do you suppose its possible the air in the tire could take a different path to arrive at the finish line ahead of the tire?