Let me guess...carbon rims?

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http://bikeblather.blogspot.com/

Probably but, I've seen this happen on aluminum rims too. But more prevalent on carbon rims.

HED Ardennes Black. I thought those would be immune.

On the plus side, they brake freakin’ awesome. And as a descending wimp, they gave great confidence.

Interesting...how did the tubes fail?

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http://bikeblather.blogspot.com/

I'd also like to see how the tube failed.

And what was the air temp?

Yeah...not enough info here. How are we determining that the tube failed because of braking heat? Did the tube melt?

Thicker/extra rim tape can solve this.. also that rim has a super wide internal bead width, so you need equally wide tape to ensure that there is no rim surface in contact with the tube.

Those rims have a very high friction coating which is also an insulator, so you are able to generate tons of heat quickly and while they are aluminum the coating helps hold the heat in the rim once it is there slowing the rate of convective cooling you can achieve otherwise, they are also quite thin, so not too different from many carbon clinchers in terms of tube failure point.

Josh

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Hey Josh,

How exactly would a tube fail due to heating up of a braking surface (carbon or aluminum)? I too thought it was a myth. Does the tube melt?

Or are we thinking that the heat of the sidewalls causes a massive pressure increase beyond what the tube can handle. So if I'm running 75 psi in my latex tubes (25 mm contis and 20 mm internal width rims), at what pressure would they fail...130 psi? And how much heat applied to the rim would it take for the tube to get to that failure point?

Would butyl have prevented either case above?

I suppose I could buy that the increase temperature caused the tube to gain maybe 5-10 psi...and that in turn caused the tube to seep into the spoke hole of a poorly taped rim...or seep out of a small sidewall cut that wouldn't have happened if the rim wasn't hot (thus the tube pressure did not increase). But my simple mind has a hard time believing that the rim could get so hot, that the tube pressure could increase to failure point. I mean...at a certain point...wouldn't you notice how crappy the ride becomes?

Did Lance or Bobby change it for you?

There were lots of hands jumping in for a fast repair. So unfortunately the tube got thrown out before I could save it. I tried to locate after the ride to see exactly what the failure looked like as well, but no joy.
Ambient air temp was around 70° F.

This is probably a major contributor. I am running Velo Plugs, so there is maximum contact between the tubes and aluminum. Never considered that potential problem when I chose Velo Plugs.

Hmmm...the edges of the Veloplugs have never quite looked "latex safe" to me anyway...

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http://bikeblather.blogspot.com/

Are you sure about that? As I recall, the "coating" on the Jet Turbine track wheels is just typical black anodize. The "higher friction" is the result of the pattern engraved in the brake track. It's not a PEO coating, as far as I can determine.

In other words, I don't think the coating would be any more of an insulator than what's on a typical anodized rim.

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http://bikeblather.blogspot.com/

I would definitely defer to Josh, but I am pretty sure that Velo Plugs and latex tubes are not a recommended combination.

The way this post is written sounds like somebody discarded the tube on the side of the road. I hope that's not the case.

The tube got thrown into a sag wagon.

This is at the top of my research list now. I am also running velo plugs in my HED Jet Black 9/disc TT wheels. They have several hundred miles with no issues, but as with yesterday, anything can happen.

I pulled the good latex tube out of my front road bike wheel this morning before today’s ride, and it looks new. (I had a Cat 3 descent coming, so taking no chances.) So, if velo plugs might be bad for latex, this N of 1 was OK.

I'd give it another go with rim tape instead of Velocity plugs. If you're still sketched by latex, perhaps consider using a tubolito instead.

I did research on these when I was making the switch to latex. The common consensus I found was go with tape over the velo plugs to avoid any issues.

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2019 T-Rex Tri Series

This was exactly why I thought too, but then the weight advantage of Velo Plugs is gone. I had one disappear during a tube change nearly 10 years ago and have been carrying spares (even though I don't use them anymore) ever since.

I weighed two wraps of Stans rim tape at 12g, so that's my default method of all rim strips whether tubeless or not. Sure, Veloplugs are ~5g, but they aren't worth the limitations. The Silca rim tape is supposed to be 9 grams for a double wrap, so that's an even lighter option with no downsides.

OMG

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Thanks Josh. I think I will continue with latex, but dump the Velo Plugs and go with your rim tape in all my HED Plus wheels. Is 25mm the right width for the JET Plus rims? And, is one wrap good enough, or should I go 2? (And if I go 2 wraps, I need to order one box per wheel, right?)

I will order ASAP.

So just to confirm...the flat simply could have been a puncture that had nothing to do with braking heat, latex, or your spoke hole plugs? I'm not quite sure why you're hypothesizing unless there is additional information about the flat that you haven't shared.

Scotch Film Strapping Tape 8896 https://www.amazon.com/..._apa_i_yh4TCbBWYGT0C

Well... I had just ridden down the steepest hill in my life, on the brakes the entire time. The roads were perfect and clear. The wheels, tires, tubes were new together with a few hundred miles of no changes and perfect use. The flat occurred at the very bottom of the hill with no event (bump, pot hole, road debris, etc.) associated with the timing. The new variable was the constant braking down a very steep descent. I went with the probabilities that it was heat related.