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| Authored by: greed on Friday, May 11 2012 @ 01:24 PM EDT |
For those not following....
The centripetal force acting on the valve assembly itself can be enough to open
it, even against the spring force holding it shut. If you were to put a rock in
a sock and twirl it around over your head, that's the sort force we're talking
about. The valve has to be pressed in that very same direction to open it.
(Don't try the thing with the rock near people or anything else you don't want
to break.)
Someone did the math for a common motorcycle tire size and common valve type,
and determined it would be somewhere over 120 km/h for that particular
combination. He suggested that you should make sure your valve caps are on well
before going for a speed run on the autobahn.
Sadly, I don't remember the math well enough to remember if it gets
"worse" or "better" as your wheel diameter increases. ISTR
it was worse, and 3.14 was involved somehow.
And the gunk they keep out: that gunk can foul the sealing surface, leading to a
slow leak.
They're like $0.99 for a set of 4. A couple were killed checking a flat in a
live lane here recently. So please, spend the buck. If you don't, at least
don't get out of the car in a live lane--wreck the rim if that's what it takes,
but get off the road first.
[ Reply to This | Parent | # ]
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| Authored by: Anonymous on Friday, May 11 2012 @ 04:58 PM EDT |
My high school physics teacher told me that something constantly going fifty
miles an hour in a circle is considered accelerating because of the change of
vector.
I guess then the danger happens when it quits its accelerating and becomes a
velocity, a straight shot.[ Reply to This | Parent | # ]
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