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Old August 20th 18, 06:12 AM posted to uk.rec.cycling
Tosspot[_3_]
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Default Curious Double Tubing Incident

On 08/20/2018 06:47 AM, Bret Cahill wrote:
No flats on double tubed wheel all summer on 60 C + pavement.

Today about 14 km into the ride, no warning whatsoever, the front
wheel exploded blasting Slime all over shoes, wheels and road. The
wheel was immediately on rims.

Obviously the tubes over inflated from the vapor pressure of the hot
sealant and blew the tire off the rim. Hopefully the other inner
tube would still hold air, even if necessary at a lower pressure.
That's the whole reason for double tubing: on the go backup

Problem with that theory was the tire was still entirely on the rim.
The bead was not damaged which is usually the case in over pressure
bead blow outs.

Neither of the 2 tubes would hold air either. Until today a fourth
tube was always taken as a spare, but, like the Titanic there was too
much confidence on what multiple air filled chambers could do . . .

In town under shade dehydrated with wheel off it looked like both
tubes had ripped open in the same spot almost simultaneously, one
tube sliced open 10 cm and the other shredded for 15 cm.

There may be quite a few of firsts, onlys and never agains here but
this is probably the first simultaneous double tube blow out to ever
take place completely _inside_ the tire.

Maybe the tubes were chafing each other since the blow outs were
right next to each other, about 1:30 position with valves at 12:00
and 6:00.

That theory is no good either. The rubber along the rips was still
thick enough to hold air.

Any theories on what happened? No puncturing objects were found in
the tire.


My guess is one caused the other and I'd be taking a long hard look at
the rubber for age/chemical degradation.

'Part from that, no idea.

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