On May 8, 3:45*pm, Bill D wrote:
Not enough information to say for sure. *A too-large tube might crease
inside the tire causing weak spots but it's hard to imagine you would
be using a tube so small it wouldn't inflate to fill the tire. *Most
will inflate 2x without undue stress. * However, using the right size
is important.

My guess is the tire is sliding around on the wheel. *Since the tube
is anchored at the valve stem it will rip as the tire rotates on the
wheel. *Could it be someone used liquid soap to help fit the tire to
the rim? *Soap is a big no-no since it makes a great lubricant for
tire slip and tube failure when it gets wet.

Expensive tire-fitting goop designed to hold a tire in place is
available but in the motorcycle community, ordinary furniture polish
is held in high esteem when used for this purpose. *The big-scooter
guys bet their butt on their tires every time they ride so they tend
to know these things.

On May 8, 12:28*pm, JohnDeRosa wrote:







Our beloved 1-26 (the Karmann Ghia of sailplanes) keeps busting inner
tubes. *Like every other flight! *NOTE that there is nothing rough on
the inside of the tire or rim.

My thinking is that we have a mismatch between the tube and the tire.
The are in fact of different sizes. *I should have written the sizes
down and should have reported it here. *I will do that soonest.

So, riddle me this - If the tube is too large then it will become
pinched which is bad. *Right? * If too small, won't it just inflate to
the correct size/shape, within reason that is? *We are using talcum
powder - is this good or bad? *Or should the tire and tube be of
identical size?

Thanks for any suggestions.

- John

Find the hole in the tubes, this will tell where the puncture is
occurring. If the tire is sliding in relation to the rim, the hole
will be near the valve stem (this shouldn't be happening on a 1-26,
because the rubber brake pad bumper is in direct contact with the tire
when braking). If the hole is on the rim side (bottom of the tube),
the rim is the problem. If on the tire side (top of the tube), the
tire. You may have a piece of wire or glass embedded in the tire that
is puncturing the new tube. The tube size is not critical, but needs
to be close.

Ed