Fun video time! How many PSI to explode a 20 year-old, dry-rotted tire?
 

Answer: 220 PSI!

https://www.youtube.com/watch?v=pP6vnIuod_s

Haha, fun video! Explosions are so entertaining...

That being said, I'm probably going to keep my tires at 50 psi for now.

Not much to gain by going a much higher, anyway!

http://forkenswift.com/album/8-chart...arious-psi.gif

http://ecomodder.com/forum/showthrea...tire-2721.html

How do you know for sure...??? :confused:

You can't technically say that till you take the chart all the way to 219 psi...;)

The trick is don't let it go to 220 psi... :eek:

I would like to know, and I'm pretty sure there are other inquiring minds here that would really, really, really, like to know.



So Metro.

Do it...



Do it.

For the sake of science.

For this forum.

For the children...



I would also like to take this time to say "Thank you".

Ahead of time...

You know...

Just in case... ;)



:)

>

Good idea! I'll set up the camera on a tripod... hopefully my heirs will (a) find it near the blast radius and (b) can figure out how to post the results. :D

Cool video, thanks Metro.

I wonder what it's rated pressure is, probably 35psig for an older tire? If so, that's still about four and a half times it's rated pressure.

Typically in engineering, things are designed to a safety factor. Safety factor of 2.0:1 means that it was designed to twice the rated load. For the products we design where I work, because the failures could cause death, safety factors are 4:1, 6:1, or 10:1. I can see tires being in the same category, so I would expect a 4:1 or 6:1 safety factor. I'm impressed that the tire still has such a high burst pressure considering it's age.

Factors to consider:

1) That 220 PSI is static pressure. In driving, you'd likely see jumps as the wheel goes over bumps & potholes. (It'd be interesting to see if anyone has actual data on this.)

2) 220 PSI is cold pressure. Drive for a while and the heat will increase the actual pressure. so maybe 150 PSI or so would be the max cold inflation pressure.

I'm not going a pound over 125. I like the smoother ride of the low 100's.

Technically the split rim, well split, the tire looked fine

Don't they time warp at 88psi or something like that?

Don't forget about fatigue. In tires, that's the most important thing.

If you look at a typical S-N curve for rubber - and consider that 100,000 miles is about 6 million cycles - then the S-N curve says the failure stress is about 1/4 to 1/5 the static value. If you divide 220psi by 4 or 5, you get 55 and 44 psi. Isn't that interesting!

Of course, they did say the tires were dry-rotted and old.

Don't ever plan on running tires that old. :p

Though when I stop to think about it, skinny little road bike tires normally inflate to 120 PSI or so.

I had a set of the really nice European Klebers (they changed when they set up manufacturing in the USofA) on my 1956 sunroof Beetle. I parked it on dirt at my brother's place for 18 months and some micro-organisms in the soil ate the tread off one of them! The flat spot made the tire unusable.

jamesqf — pneumatic tubes of a given wall thicken can withstand more pressure in a small diameter, less as the diameter grows.

I would think that higher tire pressure means the tire flexes less each rotation, so it should age slower?

Yes, but impact stresses could make it easier to puncture or blow, that said at the pressures we run it's mostly a non issue

If by that you mean less likely to crack, that would be so. But aging is more about the chemical and physical state of the rubber - how well it's strength is holding up and how well it is adheres to adjacent components. It's those things that cause the tire to fail. And those things seem to be more correlated to heat.

Heat is also correlated to pressure. Underinflated tires get very hot on the highway. I had a slow leak in my right rear and it was almost too hot to touch even though it wasn't riding the rim yet.
The other tires were about at ambient running 42 PSI.

Yet on the other end, semi truck tires get inflated to around 100 PSI.

As RedDevil says, if they get under inflated, that's when they start shedding the big chunks of tread that litter the highway shoulders.

And don't forget the reinforcing plies. They are there for a reason.

The pneumatic tire is what made the modern road vehicle possible. We think of balloons going pop, but nothing else but pneumatics will take a hit from a pothole at freeway speeds.

The Tweel is getting close to a replacement. But they need 3D printed fractal spokes

http://road.cc/sites/default/files/s...?itok=n_ALynKp
http://road.cc/content/tech-news/221397-bridgestone-latest-develop-puncture-proof-bicycle-tyre

"Retain temporary possession of my alcoholic beverage and observe the results of my actions."