Drifting, hellaflush, slammed, tire stretch blog/bash thread.

[vex]

Originally Posted by sofaking

I don't feel the need to address a whole bunch of questions directed at a point I wasn't trying to make. I'll answer some though, I find that 1/2 of them are phrased in a sarcastic or rediculous nature because they're asking about things that were clarified in the topic already. The point wasn't if you could give me a million tests and contribute the rest of your life to the concern about tire safety. I was merely stating without said information which niether of us have, we can't determine a whole lot.

I haven't seen 'em answered but if you have a post number to refer me to I'll gladly re-read them.

As for gauging proper inflation I concede, I don't know how to determine what it should be set at without feeling it out. I addressed that I fill them to 40psi, but I'm not sure what you want there. If you have an answer do share, if not... the question doesn't appear to have a point but to discredit my scientific process for determining proper tire inflation levels which I'm sure would also require math to determine anything specific.

Unfortunately what you describe isn't scientific. Tensile side wall strength is compromised with stretch.

I will offer a link to a tire that de-beaded for no apparent reason (or possibly someone deflated it). The thing is nothing can be proven in that field either without knowing 100% what all the variables are. I have personally had it happen for seemingly no reason... obviously there is a reason, but I don't know it so it's unexplained.
http://answers.yahoo.com/question/in...4221537AA4wUoh
Someone previously in this same topic even mentioned they've seen properly mounted tires debead if I remember correctly.

During normal driving conditions?

I did state that I believe you're arguing theory, I don't retract that. But I will happily clarify what I'm refering to. It's not the science you're quoting that I am calling theory. I'm arguing that the conclusion you've come to about the safety is your theory, your opinion, your conclusion. I made a graph to illustrate my point. I never said that your information on tire deformation was wrong or theory. I argued your conclusion of safety concern is jumping to a conclusion from the science and that's the part I wanted proven. Obviously when you change the shape of a material that was designed for a certain shape it will stress or break it. That's common knowledge.

Lets link two ideas here. Since you do not know how much air would be required to fill tire properly you do not know how the tire will be stressed. Underinflation will result in the previously posted picture. Overinflation will result in a blow out during normal operation. Couple that with the alteration in the geometry you now have points of stress along the tread and shoulder. The issue of a stretched tire can then be split to different points:

1. Failure due to underinflation or overinflation
2. Failure due to sidewall failure
3. Failure due to tread separation

Tensile strength of the sidewall affects the first two points. Since we're altering the geometry of the tire when it's stretched we can know by your own admission that:

Obviously when you change the shape of a material that was designed for a certain shape it will stress or break it

Thereby removing factors of safety.

To state where on this graph you should plot a point of stretched sidewall failure would be only theory, speculation, guessing, whatever you care to call it without a pile of math that niether of us want to do, and only one of us knows the formulas (hint: not me).

And I'm attempting to get you to understand the math so I'm not wasting my time. Additionally what tire would are you desiring?

As for your diagram...

Is this what you want? teach away.

Your forces are off. Displaced air is not needed and can be removed (unless we have lighter molecules than air). You're also missing a normal force (acts perpendicular to the tire) that keeps the tire from pushing through the ground.