General Cycling Discussion - Brand new tube with puncture

I opened a brand new Bontrager tube this afternoon. Before placing it in the tire I gave it two quick pumps only to have the air escape out of what looked like a snake bit flat. Is this common? I guess I could complain to LBS or Bontrager, but I'll probably just patch it(who knows if they would believe me that it was that way out of the box). Its just annoying to buy a new tube and find it is already punctured.

Seems that way. Last summer I had many problems with new tubes being defective.
The brand or price didn't seem to matter. 28 flats

It happens sometimes. I had a flat with a poorly formed Bonti tube last year. There could be other weak spots in the tube, so returning rather than patching it might be a good idea.

I check my tubes before I leave the shop. I opened a box to check the valve length while in my truck ready to leave a shop. I noticed the tube had slots in it. Looked intentional. Took it back in and the shop dude checked some of the other boxes and found others. So now, I always check at the counter or before driving off.

There not making it any easier for us are they?.

Everything has a failure rate but I don't check bicycle inner tubes before using them and I've never ever encountered a problem that I could trace to a defective inner tube.

I've worked in bike shops for around a decade so I suspect I've fixed a lot more flats than the typical rider.

I'm not saying that it never happens, I just think that it's one of those things where the degree of discussion exceeds the degree of truth.

Bontrager had a bad batch of tubes a couple of years ago. perhaps you got an old stock tube. Tkae it back the shop will give you a new one. Make sure you thake the tube and the box os the shop can get credit form trek.

Everything has a failure rate but I don't check bicycle inner tubes before using them and I've never ever encountered a problem that I could trace to a defective inner tube.

The tube I bought that was "damaged", I believe was intentional. Others that the shop owner found as well as the one I bought had punctures ONLY at the points were the box opens. No doubt some butthead getting his kicks.:mad:

Other than that like you, I have never had a defective tube. I've seen claims from other riders crying foul but after "witnessing" their technique (exact same riders) on roadside falt repairs, I believe it's operator error.:thumb:

I've had one defective tube. Didn't have many miles on it, was doing a supported ride. All was good, pulled into the second rest stop. ate a bit, blathered with some of the folks, and then came back to my bike to find the front completely flat. it had been fine before i racked it. fortunately there was the mobile mechanic van there, and he took a look at it. The valve had completely separated from the rest of the tube. I guess using the tube just put stress on an already poorly made join of the valve and tube, and riding it that day caused it to give way completely. Swapped it out for another, and no problems. I would say that is a poorly made/defective tube, but the one other flat I've had was not a defect, just a plain old rock stuck into the tire and nicked the tube.

I would say that is a poorly made/defective tube,


Did you use the nut to stabilize the valve on the defective tube when you inflated it that morning?

yep. snug, but not tight enough to pull on the valve.

rode that tube about 200 miles, then that day, it decided to give way, while i was off the bike. damnedest thing, but when the mechanic guy popped the tire off, the valve was not attached to the tube.

yep. snug, but not tight enough to pull on the valve.

rode that tube about 200 miles, then that day, it decided to give way, while i was off the bike. damnedest thing, but when the mechanic guy popped the tire off, the valve was not attached to the tube.

About two years ago I bought a pair of Bontrager 26 x 1.95 tubes. Installed them on my Navigator. Failed quickly.
Since I worked in a tire plant I took a close look at the valves. Turned out that the rubber around the brass valve body did not bond completely to the brass valve body. Air in the tube simply pushed up along the brass where the rubber had not bonded to the brass. The rubber surrounding the brass simply bubbled and then split. When the Schrader valve was assembled the brass body did not get a good coating of adhesive before curing.

Then there were the two Kenda tubes that came on the wife's Raleigh Detour 3.0. Both tubes failed in the first month she rode the bike. Where the rubber base pad of the Schrader valve joined the tube the rubber had stretched to a paper thin state as the tube was being cured. When I pulled those tubes for replacement I cut the valves out for a look under the microscope. The valve assembly rubber base that attaches to the tube was square, rather than round. All four corners suffered this stretching during the curing of the tube in the curing mold.