Really Odd Flat w/Sealent

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Posts: 63
Joined: Wed Feb 01, 2012 12:34 am

by rgamble

Earlier today I hit a small rock at an oblique angle with the rear wheel. In high gear going straight at about 30 mph with a nice tail wind. A big thunderstorm the previous evening had washed some junk on to the road. Dodged a pile but caught an outlier.

The tire was a Continental Force Comp 24* tubular on a Bora 50 with 50 ml of Continental Revo sealant.

Flats happen even with sealant. No big deal. Here's the wierd part:

No sealant came out and no cut was detectable although when I removed the stem extender the sealant drained out. The Revo in question was from a new bottle and was thoroughly shaken/mixed about 2 weeks ago when inserted.

I wondered about this the rest of the way home & could think of no explanation. As in if the air came out there must be a hole somewhere. Even if I couldn't find the cut/hole the sealant would. Anyone have any thoughts?

Baffled in Maryland

*a Force Comp 24 on older model 20.5 mm rim Bora 50's is a tiny bit wider than a Comp 25 measured with a caliper. The Comp 25 was on the front & the Force Comp 24 on the rear.

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by FIJIGabe

Sounds like a "booger" to me. This happens when the sealant coagulates in one spot. It seems to me like all the sealant pooled near the valve, as if there was some sort of obstruction (the aforementioned "booger", maybe?).
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by alcatraz

When you realized you had a flat and were slowing down, if the pressure was low enough wouldn't his mass pushing on this "booger" have teared it open?

Where was the cut in the tire? Doesn't sealant have difficulty to seal sidewall punctures? Maybe you got some kind of tiny side puncture hard for the sealant to reach until pressure was either low enough and it sealed or never actually sealed, just was able to hold the lower pressure.

To me sounds like a leaky valve. Maybe when the sealant came in contact with the valve from the inside it stopped leaking with some pressure left in the tire.

Is your valve core in the extender or is it in the tube's own valve?

Do let us know what it was. This is kind of interesting. :D (I've never run tubulars myself)


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by rgamble

To alcatraz's point:

The valve core was inserted in a 30mm Continental extender . The extender had teflon tape on both ends.

As noted no cut/hole was observable, either visually or by a failed sealant outflow. I took my time looking as the situation was so strange & it was a perfect August afternoon in the middle of nowhere.

I've had good luck with Revo in the past although on occasion the sealant has failed. I remain mystified how a leak/cut/hole big or small at 95 psi would elicit no outflow although the "booger" scenario is amusing.

I'm going to chalk it up to either the Russians or the solar eclipse. Maybe both.

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by WinterRider

rgamble wrote: I'm going to chalk it up to either the Russians or the solar eclipse. Maybe both.

Russians... no doubt. :smartass:

Switched to Orange Seal on my new set.. one of our best wrenches locally uses it. Time'll tell.

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