Page:Popular Science Monthly Volume 90.djvu/127

 Popular Science Monthly

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��destruction of the tire hastened. Injuries to the wheel and tires are by no means warranted by the sHght advantage gained in point of convenience to passengers.

Rim Cutting

Fifteen, even ten years ago, tht beads of rims could cut a soft tire. Nowadays, rims are so ingenious- ly designed that only a bat- tered section will force itself into the tire. The hooks of a clincher tire may chafe a soft tire because the hooks of the side rings cur\'e in to grasp the bead. Under-inflation is there- fore to be avoided. That ap- plies to all tires regardless of type. A blow will bend a rim flange and form a projection which only too easily digs its way into the tire. Since rims are made of steel they rust. Rubber and rust are enemies. A little rubbing with emery paper and a little preservative coating will save many an expen- sive tire.

Because side walls must be thin they are vulnerable. For that reason car tracks should be avoided. The rails cut through the rubber at the edges of the tread. Cobble- stones never provided an ideal automobile pavement; but a quarter of a mile of cobble is preferable to a gouged tire.

Anti-Skid Devices

Anti-skid chains and silnilar devices are often fj a necessity. Apply them k tightly and forget to re- I move them, and the tire will show the result in deep cuts. Rubber yields; metal does not. A dull knife will pass through cheese; and a dull chain will cut a tire. Besides, any extra weigh t A sudden applica- ^^"^ additional heat, tion of the brakes and rubber is very produced this sensitive to heat-

���Above: How a tire is dented when running over a sharp stone. Just as when you break a stick across your knee, the fibers farthest from the jjoint of contact are the first to give

��On the inside of a tire, large break in the fabric. This re- sulted from an accident, the wheel passing over a stone.

Not the slightest mark or indentation on the outside of the case was left ( note X in section showing outside). The effect is just the same as if the tire had received a series of hard blows from a big sledge hammer

The rubber of a tire suffers chemical de- terioration from oil, gasoline or acids. Drop any of these liquids upon a tire and it is just as if you had dropped vitriol upon wood or iron. Wip)e away the gasoline or the oil which may have been accidentally spilled upon a tire, and never allow the wheels to stand in puddles of oil on a garage floor or a roadway.

Light has a strong and harmful chemical action upon rubber.

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