We joined the flat tire mono club this past Tuesday, only we think ours had a
different
cause, not rubbing of the tube in the tire.
We have been doing a lot of training on a hard surface runway. The tire and
tube
had in excess of 500 landings on it. We thought before Heather flew on Tuesday
that the tire looked a little low and thought the same before Jim flew after
Heather (she did 7 T/O and ldgs). On Jim's 7th landing, the plane slowed
quickly and there was a smell of rubber.
When we took the wheel/tire apart we found that the tube was perfect except the
valve stem was pulled off. No holes or rub marks on the tube. Tire was damaged
with a couple of broken cords and a cut on the outside from the wheel.
Our conclusion is that the tire was low (we normally run 18 psi) and over the
course
of 14 T/O and ldgs with some swerving on the runway, the tire pulled from
the bead of the wheel and rotated causing the valve stem to be pulled off.
The damaged tire was a US Speciality Tire AIR TRAC size 7.00 x 6 6 ply rating
and
the tube was a Cheng Sing (we think we got the tube from Europa UK).
We were able to get a Goodyear Flight Custom II tire locally and fitted our
spare
tube that is Chinese and purchased from Wicks Aircraft supply, Part Number
TB-MTAT8X6 (tubes with the 90 deg valve stem are not listed on Dresser Tire or
ACS websites). The only marking on the tube is "Quality Assured" and some
Chinese
characters! The new tire seems to have a flatter tread and doesn't bulge
as much. Landings yesterday with it on pavement were no different than
previously.
We always use a lot of talcum when fitting a tube. We inflate a new tube
outside
the tire first to get out wrinkles. Then we deflate it, talcum it (talcum
the tire too), insert into the tire and inflate. Then deflate again, and fit
the wheel (usually twice since we forget the spacer!!). Inflate again and
deflate
again. Finally inflate the final time to 18 psi. Be sure the valve stem
is aligned with the red dot on the tire for balance.
When we got our Europa wheel, we found the opening for the valve stem was quite
rough. We filed and sanded it to make it as large and smooth as possible. We
used Scotchbrite to clean the wheel before fitting the new tire and tube. There
was a lot of rubber debris on the bead and even inside the wheel.
Jim & Heather
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