My main wheel recently developed a leak, losing about 1 psi per
10 minutes. On removing the tire and tube, a piece of stiff
cellophane type tape, irregularly shaped and about 1cm square,
was found inside the tire at about the position where the leak
was found in an abraded area of the tube. There were several
linear abrasions in an area about 1.5 cm in diameter with the
deepest being a linear cut about 4 mm long near the center --
the source of the leak. This area is in the sidewall, just
above the tread area, the point where considerable flexure occurs
with the low inflation pressure used on the Europa. The tire is
a McReary Airtrac 7.00X6.
Not having a lot of experience with tubed tires, I am unsure
whether this little piece of tape could have caused so much
damage. The tape was folded back on itself and appears to be a
random scrap. It is not a type of tape I have seen previously so
it was probably in the tire when delivered. Anyone seen tube
damage from a similar benign appearing object?
In addition, I had noted about 1/8 inch movement of the tire on
the rim (based on the slip marks) prior to the leak developing.
I raised the tire pressure from 18 to 21 psi after noting this
slippage and had made about 8 flights at the higher pressure
before the leak developed. I initially expected the leak to be
near the valve stem, caused by the observed slippage, so the
abrasions on the tube were a surprise.
A second surprise was that the tire separated from the rim very
easily using only hand pressure -- tires are usually difficult
to remove from the rim. In fact, in replacing the original turf
tire I had to take it to a tire shop to have that tire separated
---From this same rim. The relatively loose fit between the McReary
tire and the Europa rim may be the cause of the observed
slippage... Anyone else noticed this loose fit? Should some
type of stickum be used on the rim to avoid slippage?
More random observations: the tube (and/or the inside of the
tire) seemed to be covered with a slippery silvery black powder.
I assume this is normal and meant to lubricate the tire/tube
interface; best guess is that it was on the inside of the tire as
delivered but I don't actually recall. On some areas of the tube
there seemed to be a thin layer of something similar to rubber
cement and the black powder is embedded into it - it is possible
to rub this stickum and then pull little stretchy pieces of it
off -- perhaps this was meant to stick the rim to the tire but
some of it got mis-placed? I assembled the tire/tube/rim a
couple of years ago and didn't knowingly use stickum or a
tire/tube interface lubricant.
As usual, lots of questions from working on an apparently mundane
item.
John N44EU
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