lets blow up some rims

Charles Ramsey wrote:
Rim makers have never explained why they make double walled rims my
theory is it allows the rim to take a higher pressure while keeping the
weight down. When I was young and foolish I blew up a super champion
model 58 rim at 170 psi. The model 58 was a common rim on tandems in the
70's often used with a schwinn hp tire at 100 psi. The model 58 was made
by squashing a tube it was replaced by the model 59 which was an
extrusion so it should take a higher pressure. It is easier to remove a
tire on a single wall rim than on a double wall rim often without tools.
Specialized published the blow off presure on their tires in the 80's. I
recomend using a long hose on your pump and placing the rim in another
room for your test. Better we blow up some rims in the lab than have
them blow up on the road. People can then choose an appropriate rim for
the tire pressure they use. You may decide you don't need the hassle of
double wall rims.



Cross bracing in double wall rims helps the structural integrity. Check
the dual level bridge design by the new Hong Kong Airport. It is able to
handle 200 MPH typhoons. A single level bridge just was not an
engineering practicality. I think your ideas have much more danger than
merrit. Current double wall rims aren't a hassle and are an improvement
over single wall rims. However, I have a pair a single wall black Araya
26" rims that I would be happy to unload at a very reasonable price to
anyone who wants easier tire mounts.



--

o problem. I use box channel touring rims on mt tourer. And my mountain
bike never get inflated above 50 psi

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"May you have the wind at your back.
And a really low gear for the hills!"

Chris Zacho ~ "Your Friendly Neighborhood Wheelman"

Chris'Z Corner
http://www.geocities.com/czcorner