Latex Inner Tube Failure

[bens]

I had a crash during a TT yesterday at speed in a corner which either was a result of a puncture or caused the puncture. I was just moving from the basebar to the skis when it happened. Skis were twisted, but whether this happened as a consequence or a result I can't say as it all happened a bit fast.

Talced tube when installed (~9 months ago). It wasn't ridden over the winter and stored in an unheated garage, but have raced once on the wheels 2 weeks ago. Installed on a 2016 Zipp 404 with Conti GP 5000 25c. It is a Bontrager XXX 25/30 tube and was at 85psi. Rim tape on the wheel is a bit dimpled but is intact with no visible damage. Road surface is classic UK (rough) but there were no potholes.

Any ideas on cause? I'm keen not to repeat as was quite painful!

[eins4eins]

Did you clean the wheel or bike before putting it away?

[bens]

Not that I can recall. The wheels only get used on dry days so are rarely cleaned.

[Miller]

Did the tyre come off the rim?

[bens]

Did the tyre come off the rim?

No it stayed on the rim. The wheel was knocked out of true, but not so badly I couldn't ride home after.

[usr]

Did you clean the wheel or bike before putting it away?

The multitude of non-interconnected (I think?) holes certainly do make this an interesting specimen. Lacking a better explanation my mind has wandered into a similar direction, perhaps some form of contamination.

Or maybe a case of the tube sneaking between hook and bead that through chance failed to lift the tire out of the rim?

[eins4eins]

I thought of contamination from cleaner or similar as the damage looks like corrosion. Either the tube got into contact with something before installation or something dripped through the spoke holes. Later seems more plausible and the part were the tube is damaged was at the bottom of the wheel when you stored the bike over winter and it had time to eat through the latex.

[bens]

To give more context/support for the diagnosis:

The wheels are stored off the bike over the winter, but once racing has started the wheel is stored on the bike which is hung off the wall by the front wheel. They are then used every week or so, but this does result in the weight of the bike essentially pushing the deflated tube and tyre together. Maybe the tube adhered onto the tyre? I had ridden about 10 miles to the start of the race and had about 5 miles race pace before the puncture.

I usually give my tyres a wipe with my hands on the start line to check for any debris in the tyre so would have noticed a stray green tube. Most of the holes are not interconnected, but the dark patch in the middle is a big flap as well as holes.

[usr]

The part I find most interesting is the bottom hole, where it looks as if the thickness was tapered off over a much bigger area towards zero thickness at the hole. It's that apparent gradient surrounding the hole real of a camera artifact?

[Nixster]

Looks like adhesion of the tube to either tyre or rim tape which has ripped the tube when cornering forces caused some movement inside the tyre. As to what caused the adhesion I can only guess.
In terms of stopping it happening then talc on fitting like you said and periodically unmounting the tyres to inspect them would be a good shout.
Strange stuff latex both surprisingly robust and worryingly fragile at the same time

[Hexsense]

If it's the real talc, it wouldn't cause tube to adhere to tire.
But most baby powder aren't talc. Most other white starch act like glue when wet.
You know for sure it's talc and verify it with water, right?

[ms6073]

Looks like a pinch flat to me and from the the looks of it, that was a long time in the making. When I still used latex tubes, I had a couple instances of side wall blowouts that were due to the latex tube getting micro pinched between rim and tire bead which took a while to finally puncture. While latex tubes are extremely durable, if the tire pressures are not maintained above ambient pressure the tubes can easily migrate a small amount between rim and tire bead, which is especially true of supple, high performance tires.

[bens]

Thanks for everyone's feedback. I'm just keen to establish a corrective action and prevent it from happening again. I used Johnsons Baby Powder which appears to be 'talc based' so probably worth buying some actual talc.

For the pale fringes around the lower holes, it's not a camera artifact but seems to be a stress mark. The material is not noticably thinner there. In terms of location to the valve I've added a second picture.

I've also ordered some new rim strips as a precaution as well.

Thanks again!

[ms6073]

When you install the new tube, I would suggest that you slightly pre-inflate the tube just enough so that it has shape, anymore and it will bulge. After the tube is installed but before you inflate, carefully inspect the bead all the way around on both side using your fingers to pull back the bead at a slight angle towards the center channel of the rim. This allows you to inspect the rim/bead interface to ensure that there is no part of the tube pinched between tire and rim. Once you have inflated the tire, you will need to top it off every few days otherwise the tubes low pressure coupled with temperature swings can allow the tire carcass to expand or contract enough to pinch a small bit of tire and it could be days to weeks later before a puncture occurs.

[pdlpsher1]

Latex (especially the thin, lightweight ones) is prone to creep at high pressures. They will find and creep into the smallest openings, such the gap on the edge of cotton rim tapes, and most notably the crevice between the tire's bead and the rim. This is why Continental doesn't sell a stand-alone latex tube but they put latex in their high-end tubulars racing tires. Tubular racing tires are round and don't have irregularies that latex can creep into at high pressures. For clinchers, latex is OK as long as you use tubeless rim, use thicker/heavier latex such as the Vittoria latex, and run less than 70psi. If you use the lightest latex and also run very high pressures, yes, you're playing with fire as blowouts can happen even when the tube is installed correctly.