manner to the old double spoke lacing formerly used on light automobiles and widely applied on bicycles and motorcycles.

A typical triple spoke wheel of Houk manufacture is shown at Fig. 22 A, while the method by which it is fastened to the master hub is clearly shown at Fig. 22 B. Most wire wheels are made so as to be easily detachable from a master hub which is not removed from the wheel spindle or axle and which is supported by the bearings or axle shafts. The wire wheel is built up with an auxiliary pressed steel hub as a basis which is provided with a series of holes to fit over driving pins attached to

the flange of the master hub and which is formed on the inside with two tapered seats, the angle of the tapers being opposed to each other. One of the male tapers forms part of the master hub which is shown at B in place on the front wheel spindle while the other male taper is on the locking nut. When the lock nut is screwed onto the threaded end of the master hub, which is sometimes termed the inner or fixed hub, it forces the female taper on the inside of the pressed steel wheel hub against the male taper on the master hub. The torsional force is applied to the wheel through substantial driving pins which engage with registering holes in the hub flanges. A spare wheel with fully

64

PNEUMATIC TIRES AND RIMS

inflated tire may be carried and a quick change made in event

of a puncture.

Pneumatic Tires and Rims.-The pneumatic tire of the pres ent day is invariably of the double tube type and is composed of two members, the inner tube and the shoe or carcass. The inner member is utilized to retain the air and is made of a very pure rubber, about an eighth of an inch thick for cars of average weight. While this tube is very elastic and is air-tight, it would not be strong enough or have adequate resistance to be run directly in contact with the road surface; therefore it is necessary to protect it by a shoe composed of layers of fabric and rubber composition. The shoe member is provided with beads on its inner periphery designed to interlock with the rim channel, as shown at Fig. 28. The air is introduced into the tire through a simple form of automatic valve which is securely attached to the inner tube. As the inner tube becomes distended by the air pumped into it, it forces the beads of the tire outward and clinches the shoe so firmly in the rim channel that it will be impossible to dislodge it without the use of special tire irons, and then only when the air pressure is relieved from the inner tube.

In order to reduce the time occupied in changing tires, which is needed to adjust the shoe properly and blow up the inner tube, a number of demountable rims have been devised. The wheel felloe carries a metal rim, and to this is attached a second member on which the tire is mounted. The tire-carrying rim may be securely attached to the wheel by means of suitable and quickly operated clamping bolts, rings or wedges. When demountable rims are fitted, instead of carrying the usual deflated spare outer casing, fully inflated tires are carried on rims similar to the demountable portions, and when the tire is punctured the damaged one and its rim are removed as a unit and a new, fully inflated member replaced. When it is necessary to remove the shoe, as in the ordinary single-rim construetion, the operation of replacing a tire will take from ten to fifteen minutes under favorable conditions, but with quickdemountable rims the operation of changing a tire will take

only two or three minutes. Demountable rims are more expensive than the simpler forms, but the convenience and elimination of time-consuming delay, as well as the saving in labor, more than compensates for the increased cost of equipment.

Numerous forms of demountable rims have been devised, but few have survived the test of time and have received general application. At Fig. 29 a combination of quick-detachable and demountable rims is shown. With this construction the advantages of both types are obtained without disadvantages of any moment, excepting those of cost of equipment. The quick-detachable type of rim makes it possible to change the tires very easily, should this be necessary, and makes for more easy removal for repairing when the damaged tires are restored to their efficient condition. In this form the tire-carrying rim is held on the felloe band by a clamping collar mounted on the stud and forced in place by a nut on the outer end of the stud. The construction is so clearly shown that its advantages will be readily understood.

66

SUGGESTIONS FOR OILING

CHAPTER II

GENERAL STARTING AND DRIVING INSTRUCTIONS

Suggestions for Oiling-How Motor Should Be Started-Handling Spark and Throttle Levers-Why Spark is Advanced-How Greatest Fuel Economy is Secured Controlling Cars With Friction TransmissionPlanetary Gearset Control-Operating Sliding Gearsets-Stopping the Car-Steering Wheel Position-Conventional Control System-Clutch Actuation Important-Shifting Gears Easily-General Driving Instruc tions-Rules of the Road and Motoring Courtesies-Things to Remember.

Suggestions for Oiling.-One of the most important points to be observed in connection with gasoline automobile operation is that all parts be oiled regularly. It is not enough to apply lubricant indiscriminately to the various chassis parts, but it must be done systematically and logically to secure the best results and insure the economical use of lubricant. The most important parts are the power plant and transmission system, and the engine is but one point in the car that must be properly oiled at all times to obtain satisfactory results. Some of the running gear parts are relatively unimportant, others demand regular inspection and oiling.

A very comprehensive oiling chart is presented at Fig. 25, this showing practically all of the points on a modern car that require oil as well as giving instructions regarding the character of the lubricant needed and how often it should be applied. Some of the points are governed by special instructions, these being the clutch, transmission case, timer and rear axle. The points of the clutch which need lubricant vary with the form of the clutch employed. Multiple-disk types which run in oil must be kept filled up with the proper grade of lubricant. At the other hand, cone and dry plate clutches work better without

any lubricant between the surfaces. When a cone clutch is employed, it is sometimes desirable to soften the leather facings with a little castor oil or neatsfoot oil, if the action is beginnin to get hard. A transmission gear case which is moderately tigh can be filled with a good grade of steam engine cylinder oil, and real heavy grease should not be used if the transmission shafts · run on ball or roller bearings. A heavy cylinder oil will have sufficient viscosity to cushion the teeth of the gears against shock and at the same time it will not be too heavy to flow into the bearings and lubricate them properly.

Neither the transmission case nor the differential case of the rear axle should be filled with the heavy "dope" widely sold, which may contain wood fiber or cork particles to make for more silent gear operation. If gearing is noisy it is either because it is worn or out of adjustment, and the use of nostrums and freak lubricants will not improve their operation. The rear axle differential housing should be filled with a medium, pure petroleum grease as it is possible to get, those having about the consistency of vaseline being the most desirable as lubricants Light oils should never be used in either the transmission gear case or in the rear axle housing, because these will not stay in place, will leak out and will not have sufficient body to cushion the gear teeth.

The only other point on the chart which needs explanation is lubrication of the timer interior. This should only be oiled when it is a roller contact form, as on Ford cars, and then a few drops of dynamo, magneto or spindle oil applied to the roll and the contact segments once a week is all that is necessary. If the timer is a form using platinum contact points, as on most cars, it does not need any lubricant. Never use graphite grease or any heavy oil in a timer or distributor case because these will not only interfere with regular ignition by short circuiting the current, but they will clog up the timer and prevent the roller establishing proper contact with the segments.

After a car is oiled it is well to go over all the expose joints with a piece of cloth to remove the accumulation of su plus oil or grease on the outside of the parts, which serves