I’ve only had a tube violently rupture on me a couple of times… and today was one of them.
Before we get to the feature, I did change out the rim strips in the Sedona’s rims.
The stock rubber rim strip broke while removing the previous tube that had problems caused by the lovely Slime I installed. The old rim strip snapped right at the valve hole, which is where the rubber is the thinnest.
This gave me the perfect opportunity go install (new) thicker cloth rim strips on both rims. I installed an old Ritchey cloth rim strip I had salvaged from the Huffy Superia on the front tire over the summer, but I decided to just go ahead and replace it, too.
Since I paid for shipping, I went ahead and purchased a pair of Kenda tubes for $12.
After getting the new “socks” on the Sedona, I also installed the new Kenda tubes.
Included with each tube was this piece of paper that I’m assuming was instructions of some sort. Obviously, it’s in Chinese and I can’t read it. Thought I’d share because of the cartoons on it.
Either way, I got both rim strips installed and situated. I installed the front tire and got it up to 60 PSI without any problems.
But, the rear tire was a different story.
I got the rim strip installed and got the tube/tire all installed. I pumped the tire up to around 60 PSI when I heard a dull “tink” and the rush of air while the tire rapidly deflated.
My worst nightmare – having a bike tire blowout in my apartment – finally occurred. (Thankfully, it wasn’t a “full blowout.” Just a slight rupture.)
It definitely wasn’t caused by over-inflation or a tire bead that loosened. There was no explosion or “BANG” and I didn’t see any bulges or anything.
My mind instantly went to the valve stem. I’ve had my fair share of valve stem failures, either through the valve stem separating from the vulcanization patch or, although much more rarely, that vulcanization patch separating from the tube.
Kenda tubes have been known to have valve stem problems, specifically that vulcanized patch separating from the tube. I had it happen on the Pinnacle a couple summers ago, and apparently I’m not the only one. YouTuber “BikemanforU” issued a “service bulletin” for Kenda/SunLite tubes failing with the same exact problem I had a couple summers ago.
But this wasn’t that. I removed the tire and found the culprit:
It appears the tube split right at one of the seams.
Next, I looked at the rim strip. I doubted it was a rim strip problem as usually those result in a “star-shaped” rupture. The tube squirted some of it’s talcum powder on the rim and rim strip, making locating the area where the tube ruptured easy.
The rim strip was installed properly the entire circumference of the rim. The rupture appeared to have occurred between two spoke nipples – so those couldn’t be the culprit. There’s no sharp burrs or edges anywhere in the rim – it’s smooth all the way around.
I’m puzzled. Most likely a defective tube, which isn’t new from Kenda.
I don’t know why I have such bad luck with Kenda tubes. (Their tire casings are fine… the tire casings installed on the Sedona currently are the stock Kendas.) Seems like every time I buy one they’re defective in some way.
It appears I’m going to have to eat this one. The seller apparently doesn’t offer free returns, and the other tube is still holding fine. For now.
Update (10/27/2019)
I gave the popped tube a new lease on life.
I installed the good tube in the front tire originally, but removed it and installed it in the rear tire. Before doing so, I tried something I’ve never tried before.
I split open the popped tube to make a “jacket” for the good tube, which will make it somewhat (although not much) more puncture resistant.
Another thing I was able to do was to limit the length of the valve stem by threading the valve stem through the valve stem hole on the popped tube “jacket.” The reinforced vulcanization area on the popped tube will limit how far the valve stem goes through the rim. As long as it’s not too short, it doesn’t affect the operation of the valve. Rather, it’s more aesthetic and can protect against putting stress on the valve during inflation.
After getting the rear tire back on the rim, I hesitated to inflate it. (After all, the rear tire was the one that ruptured the other day. I even thought about going outside to inflate the tire in case it repeated and this tube ruptured.) I inflated the tire to around 55-60 PSI, where the tire previously ruptured. Waiting for a pop or psst, I was relieved when nothing happened. The tire held fine.
I’ve kept almost every tube I’ve had pop on me. The only exception is the Michelin Protek Max and the ones I filled with slime, as those just make huge messes. I hope to someday do a project or post on some of the ways to reuse and “upcycle” old tubes.