Try putting some electrical tape or some other smooth tape over that spot and see if it fixes it.

The electrical tape won't hurt but it looks to me like you got a bad batch of tubes and they're failing where they were joined. That does not look like abrasion or a puncture but just a bad tube joint.

I'd buy a couple of new tubes, probably a different brand. In general there's nothing wrong with the Michelin's you have but I'm guessing you got unlucky with the batch you purchased. I had a few that did the same thing a few years back, have used them without issues more recently but for a while when to Vredstein and Challenge when that batch of Michelin's gave me trouble.

Good luck,
-Dave

Thanks, I'll put the electrical tape on. These tubes actually are Bontrager, but I took your suggestion and have some Challenge tubes on order right now.

i race and train on Vittoria Latex... only flatted on a direct pallet staple in the last 2 years, tires zipp FC with zipp tape band and conti 400s tires

The tube should have about zero stress on it if it's properly installed. What is your technique?

I would recommend two things. The first is to make sure you coat the tube with plenty of talc before installing and the second is to be very careful to not wiggle or bend the stem when pumping up the tire. This may not be your issue but i was getting ripped tubes in that area until my mechanic told me this and I have not had a problem since.

Carl

Who recommends no rim tape - the disc or the tube manufacturer?

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Aaron Bales
Lansing Triathlon Team

It does look like a manufacturing problem. If you really can't see anything suspicious on the rim, assume that's the case and try a different brand.

Meanwhile, sacrifice one of the flatted tubes to cut up for patches and start by patching the other. I avoided latex tubes for a long time thinking that they're too expensive, but in the long run they're not: I'm lazy enough to throw away a flatted $4 butyl tube, but not $20 of latex!

Put it in a bag with powder. Put enough air in it so it takes shape, and then put the valve in. Fit the tube in under the tire while one bead is unseated. Seat the second bead starting at valve and working around to the opposite side. Check the entire wheel to make sure no tube is sticking out from under the tire. Inflate fully.

It's tough not to move the stem a little bit because it's a disc--typically I have to pull the valve out a little bit in order to fit the pump head on it. I'll try to be more gentle with that in the future though.

The wheel manufacturer.

try r'air tubes by panaracer, difficult to get in US, excel sells them. they are nice, not sure what they use for material but have worked great for me w/o latex hassles.

I don't really buy the gentle stem thing -- latex is more elastic than butyl, not less, which means it's less likely to tear for any reason. Also, though many swear by talc I've never seen the point. Careful installation makes it unnecessary, it turns to a mess once wet, and as Jobst Brandt argued (http://sheldonbrown.com/brandt/talcum.html) bike wheels don't generate enough heat to vulcanize tubes.

Did your tubes above fail right away? Or did it take some riding around? If the failure was basically immediate -- and made a loud noise -- that might indicate a tiny whole in the rim that the (very elastic) latex is expanding through. Otherwise it sure looks like a failure in the seam.

One more step might help... once you get it all in, press down on the tire where the valve is to seat it and keep pressing as you inflate (first few strokes anyway). If you don't the tube can fold under on itself at that spot.

I've had better luck with Bontrager tubes than Challenge.

OK, I'll try that from now on. I don't think that was the problem because I've been installing/using latex now for 4-5 years, and this is the first time I've seen anything like this, but it definitely can't hurt to make sure the valve is seated.

Ha, I guess I should have ordered Vredestein's then!

Just an FYI, I use those bontrager tubes too, haven't had a failure like that, and all of mine came pre-talc'ed.

Are those Vredestein by any chance? I had 3 Vredestein latex tubes recently fail right at the seem of the black stem seal and the latex. Switched back to Vittoria.

Edit: Ahh...Bontrager, never mind. They might have the same manufacturer, though.

I've been using the same tubes for 2 seasons, I change tires and tubes for each race 3-4 weeks apart, no problems. All the above suggestions are right on. Let us know how it works out.

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"You do what you have to do , so can do what you want to do."

I had the exact same thing happen to a Bontrager latex tube a couple a weeks ago a couple of hours before a race shortly after inflating it. Sure looks like a manufacturing defect to me.

It was on a Jet Disc (with both Veloplugs and Stans Rim Tape) and since the valve cut-out was covered with gaffa it made the entire disc bulge out (since the sides are merely thin carbon covers) untill the air found a hole somewhere to escape after a second or two. I'm not sure how many failures like that the Jet Disc can handle. One thing is you have to install a new tube, but if their manufacturing defect is damaging my disc wheel I will not be too pleased.

I find this VERY interesting...

A bit of background...a few years back I had the EXACT same issue with some Vittoria branded latex tubes which were definitely a manufacturing defect. In fact, when I contacted the vendor he wasn't surprised and refunded my purchase. At that time, the Vittoria branded tubes were a green color as these are.

Well...since that time, I've not used Vittoria tubes for that reason. I started using Bontrager branded tubes a few seasons back and had no issues. In fact, I found them to be very robust. I've also recently acquired a new bunch of the Vittoria branded tubes to try again...interestingly, they're now a red/pink color instead of the green. They've been working well for me now.

So...understanding that most of these tubes are probably manufactured at 1 or 2 factories (in Thailand, most likely), I'm thinking there might be something about the manufacturing equipment that if it is "off", somehow it creates that weak spot near the splice joint. It would be interesting to see the manufacturing equipment sometime to try to troubleshoot that issue.

In any case, I'd contact Bontrager and inform them of your issue and how consistent it is. I DO NOT think it's an installation issue, and definitely isn't a rim bed issue considering you're using it on a smooth bedded disc wheel.

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http://bikeblather.blogspot.com/

Wow, thanks. I was kind of hoping to hear someone else had seem something similar to this before. I guess it's time to get in touch with Bontrager.

Let us know what they say. The most interesting thing to know would be whether you could tell the defect before mounting it somehow.

looking at how the holes are in line with the stem I wonder if the stem is not seating all the way to the rim so the tube is stretching back to fill the gap and popping on the edge of the valve hole. That or somewhere in the mfg process they are pinching that spot while sealing the ends together.