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Subject: Cycling Myths
From: Jobst Brandt
Following are various myths about cycling and why they are/aren't true.
Myth: Wearing a helmet makes your head hotter than if you didn't wear one.
Actual measurements under hard riding conditions with ANSI standard
helmets show no consistent temperature difference from helmetless
riders. Part of the reason is that helmets provide insulated
protection from the sun as well as some airflow around the head.
(Les Earnest)
Myth: You need to let the air out of your tires before shipping your bike on an airplane - if you don't, the tires will explode.
Assume your tire at sea level, pumped to 100 psi. Air pressure at sea level is (about) 15psi. Therefore, the highest pressure which can be reached in the tire is 100+15=115psi. Ergo: There is no need to deflate bicycle tires prior to flight to avoid explosions. (Giles Morris)
Addendum: The cargo hold is pressurized to the same pressure as the
passenger compartment.
(Tom ? in the University of Florida math department)
Myth: You can break a bike lock with liquid nitrogen or other liquefied gases.
Freon cannot cool the lock sufficiently to do any good. Steel conducts heat into the cooling zone faster than it can be removed by a freeze bomb at the temperatures of interest. Liquid nitrogen or other gases are so cumbersome to handle that a lock on a bike cannot be immersed, as it must be to break the lock. The most common and inconspicuous tool to break these locks is 4 inch long 1 inch diameter commercial hydraulic jack attached to a hose and pump unit.
[More myths welcome!]
More Articles by Jobst Brandt
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Last Updated: by John Allen
