BICYCLE TIRES

A BICYCLE AND IT'S TIRES

Out trust, rusty, bicycle, which we have not used for a long while, there it is in the shed house,

yes, with two flat tires. Why?

The valve stem. No 'air stops' are are impervious when there is pressure difference outside of

the inside.

Inner tubes are very porous for bikes, cheaper, nonbutyl, rubber, tubes tend to leak.

Besides this, there is little air in the bicycle tire, maybe a pint at 60 psi, where auto tires

have 5 pounds at 35 psi..

Bike tires require twice the psi and the cold temperature brings out Boyle's Law, which

postulates that for a body of air at a constant temperature, the volume is inversely

proportional to the pressure.

A bicycle wheel has more structural hazards. The spokes, thirty six of them, all are pinholes.

A flat bicycle tire gets far more attention that a auto tire, you know, like just when you want

to use the bike.

The bicycle industry has tried other materials, like plastic, which is less porous, but gives a

stiff, shock laden ride.

Porous rubber bicycle tires are likely to be with us for a long, long time. Grin and bare it.

 Source: David Feldman's Mysteries of Everyday Life, 1987. Abstract: Harrison H, December 7, 2017.