The daily morning journal and courier., 1907-02-20
WHY MOTOR TIRES GIVE OUT.
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 Them-Three Other Enemies.
 Manufacturers figure that the life of d tire should be $500 miles under ordinary usage and conditions, but 1t is safe to say that two-thrds of those in use fall considerably short of this mileage and are cast into the junk heap or sent back for replacement after they have gone no more than 1,S00 to 2,4O0 miles.
 4 writer in Country life in America says that manufacturers have ceased to ask tire customers how far he has used rim cut or blown out a tire sent in for replacement on the $500 mile part pay ment basis.
 In the early days the customer stated his mileage and an allowance was made on his figures, but now, when the tire comes in, if possible the record of it's date of sale is looked up. At any rate it goes into the hands of an expert who places an approximate mileage figure on 1t and the adjustment is made on that basis
 To figure out what service tire will give is impossible To approximate how far 1t ought to go Is easy enough but no two tires on any two machines of like weight, speed, etc, ever give the same service, even if driven over ex actly the same rais and under same conditions
 One man will drive set of tires 4.o00 miles, while another will not get half that distance. If the driver is careless and slams his car over bad roads at high speeds he can make the tire expense figure up to more than all the other operating expenses of the car combined
 The greatest strain comes in round ing turn. All these times the canvas layers of the tire are subjected to an abnormal strain that sooner or later impairs their efficiency and paves the way for blowout. This practice fur ther wears off the tire thread or out side cover q great deal more rapidly than when the car is rolling over the roads in a straight line.
 Sudden swerves of any sort have the same effect on the tires. In turning a curve at high speed It may readily be seen that, owing to centrifugal force, the car is thrown toward the outside of the curve and for the moment the whole weight is resting on the two wheels of that side. The back of the car Is thrown around and the rear wheels drag along the ground
 It was noticed in recent prominent race that one of the drivers wore out thirteen castings while another wore out only two. Both cars were alike and both were driven over the same course at about the same speed and both finished woll up with the leaders one after the other
 The car that wore out the thirteen castings rounded the curves at the greatest possible speed and the brakes times, locking the rear wheels and causing them to skid along the ground.
 The other driver when approaching the turns slackened his speed and ap- piled his brakes some time before reach ing the corner and then progressively putting them on and releasing them, and steadily slackenlng the momentum until the turn was reached; he then swung around at fair speed and get ting on the straight stretch opened up his engine and was off like a flash.
 Tires have three natural enemies that are destructive to rubber-light, heat and oil-and each has it's own peculiar effect
 When the car Is in the garage and it is not to be used for some time it is always advisable to jack the wheels up and keep the weight off them. Many owners of cars have special devices for raising the wheels from the floor and even when leaving their cars over night jack them up,
 This is no doubt beneficial to the tires and adds to the life and durability, but it Is of course some trouble. When the wheels are not jacked up and the tires allowed to stand for any iengtt of time they should be kept well in fated, and the car should be moved from time to time so that the tire does not fiatten as result of being allowed to stand on the same spot for a con. siderable length of time.
 The contrary is the rule when the wheels are lacked up and the weight taken off the tires, it being advisable then to deflate them and to take the pressure off them. The car should not be permitted to stand for any length of time, not even for half an hour, on g deflated tire.
 Rim cutting is sure to result and al times inner tubes are irreparably ruined. The only logoical and safe way to carry inner tubes is to roll each onC up separately taking care to see tha. the valve stem fs Jeff on the outside o+