110 



Popular Science Monthly 



When wheels are 

 out of alinement, 

 as above, the con- 

 dition illustrated at 

 the right results, 

 caused by improper 

 adjustment of the 

 steering apparatus 

 or a bent knuckle 



At left: Fabric de- 

 terioration and blis- 

 tering of the tread 

 resulting from neg- 

 lect of two small 

 cuts. Note the two 

 prominent "knuck- 

 les " or " bumps " 



Above: The result 

 of running a tire 

 too soft, that is, 

 under-inflated. The 

 waves of the tread 

 are due to loosening 



one of the many excellent rubber prepara- 

 tions supplied by tire makers and repair- 

 men. 



Taking Care of the Inner Tire 



The inner tube is the air-container of a 

 tire. Because it is very thin, very elastic, 

 it must be protected by outer casing. It is 

 evident that the casing will fail to act as an 

 armor; that the inner tube will be cut, if 

 pebbles and gravel work their way through 

 an external cut. Cleanliness means tire- 

 money saved. 



An inner tube must not be too large or 

 too small. If it is too large it must fold 

 itself to fit the confined space within the 

 casing. The rubber is sure to crack in the 

 creases. On the other hand, if the tube is 

 too small, it must stretch inordinately, 

 which means that it soon loses its liveli- 

 ness. 



Tire manufacturers treat the inside of 

 their casings with a white solution which 

 prevents the tube from sticking to the 

 fabric. Lubrication is always necessary. 

 Talc, powdered mica, and soapstone should 

 be used from time to time. But the 

 lubricant must be applied evenly with a 



soft rag. Dumped into 

 the case, it will merely 

 collect at one point, 

 where it will heat up 

 and burn the rubber of 

 the tube. 



Wheel Irregularities 



Wheels that do not 

 track, unevenly tighten- 

 ed clamping-brackets of 

 demountable rims, loose 

 hub-disks, bent axles and 

 bent steering rods, all 

 lead to excessive wear on 

 the tires. The front 

 wheels of most cars are 

 wider than the rear 

 wheels by three-eighths 

 to one-half an inch. A 

 variation greater than 

 this means that the 

 wheels are out of aline- 

 ment. The cause of 

 wheel irregularities is generally to be found 

 in a short or bent drag-link between the 

 steering arms. Wheels can be tested at 

 the branches of nearly every important 

 tire manufacturer and at any garage. Since 

 excessive wear may also be due to poorly 

 adjusted brake drums or unevenly clamped 

 demountable rims or bent axles and rods, 

 do not content yourself with a mere test 

 for parallelism. 



Effect of Brakes 



A car weighing over a ton, traveling at 

 forty or fifty miles an hour, has about as 

 much striking energy as a twelve-pound 

 artillery projectile. Some disposition must 

 be made of that energy when a car is 

 Tires were not made 

 Apply the brakes sud- 

 denly while your automobile is running at 

 high speed and the wheels will lock so that 

 the tires are scraped along the road or 

 pavement. You know what would happen 

 to your trousers if you were scraped along 

 in that way. A tread, thick as it is, can 

 endure much, but it cannot withstand that. 

 It will be ground off, and some of the fabric 

 plies may even be broken. Locked brakes 

 will not stop a car more quickly than 

 brakes rationally applied. 



Carelessness in driving against curb- 

 stones may wear away the side walls of a 

 tire. If the practice is indulged in too fre- 

 quently, the fabric will be exposed and the 



stopped suddenly, 

 for that purpose. 



