Mohave County miner and our mineral wealth., 1920-07-24

M
 Note-At the Truck and Tractor meeting of the Society of Automotive Engineers held in Chicago paper en- titled Relation of Solid and Pneuma- tic Tires to Motor Truck Efficiency" was read by S. V. Norton, of the 5. F. Goodrich Rubber Co.
 The following is the last install- ment of an abstract from his paper which has been pronounced by eX- perts as the most authoritative treat ment of the subject ever made. MT. Norton is widely known as a trans portation engineer, a tire expert and as the author of "Motor Trucks of America 'and "The Motor Truck as an Aid to Business Profits"
 Having reviewed the engineering features and the practical operating features in preceding installments of this series, let us now see what the operator faces in so far as tire service is concerned. As the nature and ex- tent of service of the maintenance and renewal of solid tires are we'll known, it seems unnecessary to comment on them except to say that years of study and competition have developed this end of the business to a high de- gree of perfection, so that the oper- ator can depend upon many well equipped service stations for instant attention, either in the day or night.
 The manufacture of heavy duty pneumatic tires of six inch section and larger, is, however, a relatively new development, less than a third of the manufacturers of passenger car tires have started actively to make heavy duty pneumatic tires, fer they realize that the job of building tire which will stand up under the use and abuse to which it is subjected nova. days is no teasy. Moreover the task is not finished when the tire comes out of the heater. It must be sold to the dealer, who, in turn, must not only stand behind the tire, but place him. self in position to give the truck op- orator service. This means he must install high-pressure air-punip, re pair materials and molds for vulcaniz- ing and in most cases service car for emergency calls as it must be re- membered the tire is apt to fall away from it's base and it cannot be driven home flat.
 It may be said, without fear of con- tradiction, that the tire companies themselves are not as yel prepared to give really efficient servtce lin all parts of the country. In fact, even in the principal cities this phase of the business has not been fully devel- oped. In the smaller towns there are almost no airtanks or pumps to keep tires properly inflated. Pumps on trucks themselves are reported as not always dependable, sometimes requir- ing from 15 minutes to half an hour to secure the desired pressure in a tire.
 By far the most serious and diff cult phase of giving service with heavy duty pneumatics, and that which causes the most concern to truck operators, is connected with the repair. In fact, the chief complain, in regard to pneumatic truck tires aside from their high initial cost, is that they are subject to injuries, cuts and damage generally of such ma. ture that they cannot be repaired ex. cept at the factory where they are made, or in few cities at factory branch and often they are damged be. yond all repair. This is not only ex. pensive, but frequently necessitates the purchase of more than one set o1 spares should the first set be injured while the others are being repaired Oftentimes the principal cost of pun. ctures or blowouts is due to the nee, essity of laying up trucks awaiting new tires, due to stock shortage, ol sending the damaged tires to thu nearest factory branch for repair Moreover, repaired castings frequent ly deliver but small mileage due tt the overcure of the joined portions This danger is most difficult to over come i nthe large sections due to tn, longer cure required to vulcanize thu interior portions of the new part O. the casing. No doubt this featur will ultimately be corrected.
 The tread seems to give less trou ble than the side walls which are nor, susceptible to rut wear and overload , ing abuse.