I am going to have a hard time explaining this. Umm… I blew up my bike tire and it popped out like a giant vericose vein.
So, I’ve replaced a thousand bike tires. I remember the first abortive effort I made at it when I was in like seventh grade. That was really bad. I screwed that little Wal-Mart special up badly.
Since then, though, I have successfully replaced countless bike tubes. Not that this is anything special. We all know it’s pretty easy.
But this morning I replaced a tube, filled it up, finished. Was very proud of myself. The last time I replaced the back innertube on my fixed gear, I found getting the thing lined up right again in the brackets really challenging. This time, no problem. So I walked away from the bike with the sense of a job well done.
But I came back to the bike a little bit later and the inner tube had EXPLODED out of the tire! It was all over expanded like a giant, infected vein coming out of someone’s arm! It was half in, half out. Something really gross about it.
I’ve never seen this. I can’t even explain it. It seems like if a phenomena like that were to occur it would occur as you were pumping the bike up. It didn’t, though. It happened sometime later.
I just can’t explain this at all. It does not make sense. Has anyone seen this before?
Well, I deflated the tube. Carefully put the tire back on the wheel and went all around it looking for pinches. I reinflated the same innertube (it didn’t pop after all) and set it back down.
All seems to be fine so far, several hours later.
Mysterious. And gross.
No doubt your tube escaped the confines of your tyre because the bead failed to seat properly. There are various reasons why this could occur. The bead could be damaged, did you use a lot of force on a tyre lever to pop the last bit of bead over the rim? There could be an obstruction preventing proper seating, such as a wayward piece of rim strip, a slipped section of “Toughie” liner, or a fold of tube. You can easily check for proper seating of the bead by partially inflating the tube (about 20 psi) and sighting along the tyre where it meets the rim. There is a line molded into the tyre for this purpose. This line should be the same distance from the rim all the way around. If it isn’t, you must determine the cause of the bad seating and correct it before inflating to full pressure.
The reason it took a few minutes for your tube to make its bid for freedom from the tyre is that friction held the line for a little while. Then the rubber-metal interface lost its battle for tenacity, the rubber crept outward due to the force of the air pressure, and the aneurysm occurred.
I had one explode on me recently too. It turned out that it was a defective tube. Apparently one of the seams on the tube was not heat sealed properly and it ripped apart right there in a perfect line along the seam. Scared the hell outta me!!
The same thing happened to me as I was busy over-inflating an old gum-wall tire. The tube bulged out from underneath the tire and before I could anything, it exploded. The blast that I felt makes me think I could’ve lost a finger if I’d tried to do anything to releave the pressure.
Moral: check the seating of the tire on the rim before you cram as much air as possible into your tube.
Thanks to Harv especially for helping me figure out what happened on my bike. You think they are such simple machines, but they are more complex than you realize.
I rode around on the wheel yesterday. I was a little nervous about it, but the traffic in Philadelphia on July 4th is just too awful to imagine driving or busing anywhere (I had a nightmare along these lines in my car last year – never again). So it compelled me to risk it.
My tire was fine. No explosions. I guess I have it beaded right now. I think I did it a little hastily before.