pinch flats 180 degrees out of phase

I recently hopped a curb from a parking lot to a paved trail into a
woods on a road bike-I mistook the curb for a ramp. I had 27x1 1/4 on
the front and 27 x 1 on the rear. In addition to the wider front, I
pulled up on the front handlebars to unload the front wheel whilst
traversing onto the trail. The rear received 2 pairs of pinch flats,
each pair of fang marks 180 degrees apart on the wheel. Any idea what
phenominon might pinch the tube twice?

i.e., might the rear have bounced or was something else likely going
on?


--
meb

meb wrote:
I recently hopped a curb from a parking lot to a paved trail into a
woods on a road bike-I mistook the curb for a ramp. I had 27x1 1/4 on
the front and 27 x 1 on the rear. In addition to the wider front, I
pulled up on the front handlebars to unload the front wheel whilst
traversing onto the trail. The rear received 2 pairs of pinch flats,
each pair of fang marks 180 degrees apart on the wheel. Any idea what
phenominon might pinch the tube twice?

i.e., might the rear have bounced or was something else likely going
on?



My guess would be that you may have just gotten lucky once before and
crimped the tube, but not enough to cause a failure. I top off my tires
every time I get ready to go out and still have hit some pretty mean
potholes that caused me to worry about pinch flats.

On Tue, 5 Feb 2008 19:53:11 +1100, meb
wrote:


I recently hopped a curb from a parking lot to a paved trail into a
woods on a road bike-I mistook the curb for a ramp. I had 27x1 1/4 on
the front and 27 x 1 on the rear. In addition to the wider front, I
pulled up on the front handlebars to unload the front wheel whilst
traversing onto the trail. The rear received 2 pairs of pinch flats,
each pair of fang marks 180 degrees apart on the wheel. Any idea what
phenominon might pinch the tube twice?

i.e., might the rear have bounced or was something else likely going
on?

Dear Meb,

You could get a second pinch flat by hitting something a moment or two
after the first pinch flat let the air out of the tube.

A much smaller impact and obstacle can pinch the deflated tube.

Where the second pinch occurred would be pure chance.

Cheers,

Carl Fogel