i came home today, to find my bike with 2 flat tires. my dad said he had heard some loud bang earlier, and when i looked at my bike,the tires were completely flat, and practically off the rims. anyone ever heard of this or had it happen to them? maybe its because it was out in the sun or something? i have no clue, but theres like a 2ft long slice in the tube, as if it just exploded.

Yeah It happened to me once but never again. But I also have no Idea why it happens. It could have something to do with your rim tape or strip and when it happened to me I had those flimsy old school rubber strips now I use michelin rim strips and they seem a hell of a lot better.

It's happened to me only when I was stupid enough to inflate the tire with out making sure there wasn't a pinch of tube stuck between tire and rim.

Here's my explaination:

Pressure is a physical quality of contained matter, in this case air inside a tube. Pressure is defined as the force per unit area exerted by the contained matter on the container walls (SI unit of pressure is the Pascal, which is equal to one Newton per Square Meter). When you have a gas in some container, the pressure results from collisions of the gas molecules against the walls of the container. As the temperature goes up, the kinetic energy of the molecules increases and there are a greater number of collisions per unit time. More collisions means more pressure. If you had already filled the tubes to capacity and then they were heated up (in a hot garage, for example), the increase in pressure might be great enough to pop the tubes.

Ain't science fun?

Yeah what he said...

Pretty f'n hot in Boston today. If the last time you filled your tires was earlier this week (when it was unseasonably cool) then it is perfectly logical to assume that this was the cause.

The pressure rises in proportion to the temperature rise, in Kelvin. So, if you aired up your tires at room temperature (25C or 298K) then put the bike where the temperature got to 110 deg (43C or 316K), the rise in pressure is 316/298=1.06 times the original pressure. For a 100 PSI tire, you get only 6 psi added pressure.

Assuming you have healthy tires and tubes, you would need a much higher temp rise to cause a blowout. If you have some sort of defect in either, then anything is possible.

I had a cut in a tire and the innertube was coming through. to
the point where it exploded. I only realized it after I put a new tube in and
saw the bubble coming out.

Both tires suffered ruptures in addition to the tubes?!? Now that sounds suspicious.

This sounds right to me. MKRG and Sohi pinned it. If you hear a bang then the tube has already exited the tire/rim envolope. Over pressurizing the tube (air on the inside, intact tire on the outside) isn't going to rupture anything. We routinely place inner tubes in a 10,000psi environment on the job and they just get stronger (while at pressure that is).

Assuming the tire has no cuts or the tube has been in place for awhile (so it's not the situation MKRG described) then the only thing that comes to mind is that the tire is a poor fit for the rim, with the small pressure increase being enough to unseat the tire from the bead seat. Curiously, what tire and rim combo do you have?

Jim

Something similar happened to me a couple weeks ago - I believe it was due to some of the tube being pinched under the bead of the tire, specifically near the valve, where it can be hard to seat the tube fully inside the tire (depending on the tube). The tire was fine for a couple weeks, then one morning I went out to the garage and the sidewall of the tire had blown out - separated from the bead. I guess the strange pressure and forces just finally got to it. Oddly enough, it happened overnight, and the tube didn't burst - it was just swelling out the side of the tire. Not sure if this is what happened to you, but its one thing that can happen.

Many years ago, I had just gotten home from inflating my off-the-bike tires at a gas station. I was getting the bike ready to install the wheels when one of the tires exploded through the sidewall. A few minutes sooner and it would have gone off in my VW Beetle. The sudden air pressure change would have ruptured my ear drums. Remember those air tight, floating Beetle ads? I had to roll the window down to close the doors with that car.
I think the so-so quality tire had a minor defect that took a couple of years to fail. OK, my regularly pushing those tires to their cornering limits may also have had something to do with it.
These days, ozone and UV attacking the rubber isn't helping any.

I overinflated a tire once with slime in it, i think the slime is what made it explode. Were these tires slimed?

heres my theory:

i had just filled the tires up at a gas station, to approx an appropriate pressure. the tires were pretty dry rotted, considering i bought the bike from a flea market for 20 bucks. the bike was out in the direct sunlight (im back in NJ now, til sept 6th, and it got pretty hot today) and im assuming that the heat prolly caused the pressure to increase, plus the black tires attract heat, due to the color, so that probably caused the tire to fail, because most of the bead was ripped right off the tire. they were pretty old, so i figure ill grab some continentals or something tomorow, i got tubes tonight at walmart, so the bike should be back on the road by mid-week

Ahhh... you didn't mention the dry rot on this $20 flea mkt special. I think they were on death's door from the moment you bought it, regardless of the heat.

Ah, so now we have the answer. The rotted tires simply gave way under the constant pressure. It just took a little while to happen.

Did the same thing a couple of weeks ago, bought a second hand bike with rather unused tires (but old) both ripped after a couple of days. Tires sure have a "best before"-date

This reminds me of my computer tech days you never get the information you need to solve a problem.