Arizona republican., 1916-07-16

condemned. The aim of the makers of all vehicles is to secure the II maximum of strength and power with | a minimum of weight and size. To do | this, highspeed engines, the best of materials, and the finest of workman ship are employed, and parts are re- duced to the least possible weight con- sistent with strength and durability. This is just the reverse of the ordi- nary American mechanical practice in which reliability is secured by slow speed and large size, the amount of material used and the space occupied | being minor considerations. It is, therefore, unreasonable to expect the mechanic trained in one school to un- derstand immediately and adapt him self to the ways of the other. It must [ also be remembered that no other ma chine is given the hard use and neces- | sary abuse that motor trucks receive ! The vibration while on the road will l loosen nuts and rivets, and this. if not | attended to in time, will cause serious ! trouble. Where only one or two trucks l are used, the drivers should be compe- tent mechanics and should be held re-
 
 machines. Where several are used, they should be under the direct super vision of a thorough truck mechanic that is held responsible for operation and given entire control of the drivers and repair work. His constant care will detect and remedy many incipient defects and prevent expensive and an moving break downs. With the excep- i tion of the time required for periodic overhauling, he should be able to keep the trucks in almost continuous ser vice. This will make possible the em- ployment of cheaper drivers without undue damage to the machines.
 1 Motor trucks should not be installed without careful consideration of the roads to he travelled The difference 1 between the cost of motor truck and amhauling is largely controlled by the quality of the road, and on really bad roads the motor-truc is decidedly the more expensive. Many roads are ] fatal to truck -haulage, and consider able experience is required to decide this question without an actual test of some duration Excessive grades are to be avoided, especially long ones. The ordinary truck will pull over a short 20 per cent grade with ease, but will give great trouble on a long one of half that rise unless special cooling arrangements are made. Grades great ly increase the tire and gasoline con sumption and decrease the life of the machine. Rocky roads, particularly when the rocks are sharp or loose are hard on tires Deep sand is difficult to cross. and for this class of road the caterpillar tractor and the four wheel drive truck have distinct advantages Trucks that drive on the rear wheels only cannot operate in heavy sand. Narrow or rutted roads are objec- tionable for the larger sized trucks be- cause they throw all the weight on one of the rear dual-tires from time to time, and this overlooking is in furious to the rubber. Fairly deep streams can be crossed. but mud is an absolute barrier except to the cater pillar type of tractor. Few dirt-roads will stand up under 7-ton truck, but those of tons or under. do less dam age than the ordinary freight wagon. Unfortunately. trucks are not de-
 signed to suit mining conditions. At
 Shultz We found it necessary to cut
 down the gear ratio, increase the size
 of the wheels and tires, and add , bumper or auxiliary springs Had the , grades been sleeper it would have been
 necessary to increase the cooling ca . , pacity.
 , For long hauls the motor tractor . will probably replace the motor truck , i It will operate at lower cost because the load will be carried on iron tires n and, as the table of detailed cost n shows. the rubber tires account for 22.: 7. per cent of the total Tractors trave
 more slowly than motor-trucks, bu
 the tonnage hauled on a trip is mucl f greater. They are also easier on roads .. as the load is distributed over severa trailers By using extra trailers. load ing and unloading can be done on tn, ~ road.
 The make of a truck is not as i'm 4 portant as the care it receives. Al
 most any standard make will do goo, ,. work if given careful attention, bu ,f none will be satisfactory if not wei "a cared for. Economy should not b n sought in the lubricants used: the bes . oil is none too good. Overloadin 70 should be scrupulously avoided. . truck may be made to carry man ,, times it's rated load without breakn down, but the damage is none the les Q, real because not immediately appar 70 ent. High speed. particularly if tn Ia road is rough should be avoided, sinC .. it subjects the machine to eXcessiN
 strain and vibration. Most trucks al
 now equipped with speed governor o,. but these are easily tempered with ar
 must be carefully watched. Whe ne, they are not used, the drivers shou
 be carefully instructed as to the speed os limits and compelled to respect theI
 Distillate and tops are now SUI os cessfully used on trucks, by the al
 plication of a special carhureter. TT ,,r use of these should effect a materi
 saving in the gasoline cost, whi' ,,r now amounts to almost 15 per cent