November 1, 1920 



THE INDIA RUBBER WORLD 



83 



The Development of Pneumatic Truck Tires and Tire Equipment 



Why Use Pneumatic Tires for Motor Trucks?" 



By W. E. Shively' 



EVEKV DEVELOPMENT in the transportation industry has been to- The economy of operating trucks on pneumatic tires has been 



ward a faster, more reliable or cheaper method of trans- shown by the experience of many users. There is a considerable 



porting men and materials. No one will deny that the saving in gasoline, oil and upkeep. The saving in gasoline in the 



motor truck is a very significant development in the transporta- case of five truck operators is shown in Table I; also the saving 



tion system of the world. This was conclusively proved in the in oil consumption, probably due to the decreased vibration in 



w-orld war. Most of us are of the opinion that the motor truck all of the moving parts of the truck. 



is destined to become the most important factor of our trans- The upkeep or repair cost of a truck operated on pneumatic 



portation system, judging by the events of the past two years. is much less than when operated on solid tires. It can be at- 



The development of the motor truck has been limited by the tributed to the decreased amount of vibration and the absence 



solid tire. of severe shocks and jolts. The estimated saving is from 25 to 



At first, solid tires were used on all but light delivery trucks. SO per cent. Regarding depreciation charges, as a result of ex- 



On every other type of highway motor vehicle, the limitations perience, Goodyear solid-tired trucks are depreciated on the basis 



of the solid tires were soon discovered and the solid tire was °f 60,000 miles of service, while the pneumatic-tired trucks are 



replaced by the pneumatic tire. But the tire manufacturers had depreciated on a basis of 80,000 miles. In my opinion the 80,000 



not kept pace with the development of the motor truck, inasmuch "I'les is too low, because there have been Goodyear trucks on 



as they had not perfected a large enough pneumatic tire. Tire pneumatic tires which at the end of 250,000 miles were still in 



engineers, however, were among the first to recognize the short- g°od running condition. I believe that in the near future trucks 



comings, and proceeded to develop a large single pneumatic tire will be depreciated on the basis of 100,000 miles, 



for motor-truck use. DEPRECIATION OF LOADS AND ROADS 



Discussion of the relative merits of pneumatic and solid tires This is now considered by many to be one of the most im- 



must of necessity reduce itself to a comparison of the elasticity portant advantages. In hauling fragile materials such as bottled 



of compressed air with that of rubber. We think of rubber as goods and eggs, there is very little, if any, breakage. Then there 



a very elastic substance, but it cannot be compared to compressed is the easier riding made possible by the use of pneumatic tires, 



air in this respect. The reasons that motor trucks can be op- in the case of delivery trucks, the elimination of the vibration 



crated with any degree of success on solid tires are that they makes it possible for the truck driver and his helper to ride al- 



are operated at relatively low speeds and are built so heavy most continually without fatigue. This is of vital importance 



that they will endure the shocks and vibration to which they where it is necessary to drive for hours at a time. Easy riding 



are subjected. is absolutely essential in passenger buses, from the standpoint 



Two fundamental advantages result from the use of pneumatic of both comfort and speed. 



tires on trucks, increased cushioning and increased traction. In- Increased traction is made possible by the greater width of 



creased cushioning is the most important factor, because it has the pneumatic tires, their non-skid treads and their greater flex- 



a greater efifect on the performance of the truck. The cushioning ibility, which allow the surface of the tire to conform more nearly 



ability of a pneumatic tire is four times that of a solid tire of to the unevenness of the road, thereby getting a better grip. As 



the same carrying capacity. As a result of this six_ distinct ad- a result of this increased traction, we obtain reliability and safety. 



vantages are gained from the use of pneumatic truck tires: (1) By reliability is meant that it is ■possible for the truck to operate 



faster transportation, (2) economy of operation, (3) less deprecia- successfully over almost any kind or condition of road, and dur- 



tion of fragile load, (4) easier riding, (S) less depreciation of ing all seasons of the year. By safety is meant that, because of 



roads, (6) lighter weight trucks. the increased traction of the tires, the truck will hold the road 



-_...— „„™. -„„•., .»,.~ „„„„.—«., . „..,«.. .^„ better and the brakes will be more effective. This point has been 



TRANSPORTATION AND OPERATION ECONOMIES , , , , , , r , 



T^ . , . .• ■ , II- u i- »i • thoroughly proved bv the experience of many users of pneumatic 



Faster transportation or quicker deliveries result from the in- , . ' " ■' 



. 1 •• ; „.■,!»■ u ■. ■ ■ui„ truck tires. In traveling over the mountains along the Lincoln 



creased cusluomng ot pneumatic truck tires because it is possible . .° ... 



. , , ■ » „ ■ J • • J AT r . highway during the winter, this increased traction has saved 



to obtain greater maximum and minimum speeds. Manufacturers ... 



, ,■,.■,. , ^, . . ., 1 r 11 both drivers and trucks from serious accidents on numerous 



of solid-tired trucks remove their guarantee if a speed of 11 or . 



occasions 

 12 m.p.h. is exceeded, while pneumatic-tired trucks are being op- 



erated at 20 to 35 m.p.h. „., . . *^°ST OF PNEUMATIC TIRE EQUIPMENT 



_ , , , . , ., . ^^ '"Ic 't IS true that the initial cost of truck pneumatic-tire 



Table I shows the increased mileage obtained with pneumatic „,,.:.„„.,» ;., „„. , .i »i . t rj •• . -^ i. . 



" ^ equipment is greater than that of solid-tire equipment, it has 



tires by four truck operators. ^^^^^ proved by experience that this difference is more than offset 



rp J by the greater earning power and the lower costs of operation. 



^ . It has usually been found that in from four to six months the 



Operators' . , , , . . . . . , 



Details , -^ , increased cost of the pneumatic-tire equipment is completely 



Truck capacity tons 2 314 2 2 vviped out. When specially designed pneumatic-tire trucks make 



Pericd, months .....•■. 6 1 5 4 their appearance, this increased cost of pneumatic-tire cquipmert 



Mileaee on pneumatic tires 6,414 1,995 5.510 7.014 .,, , ' 



Mileage on solid tires 4,476 675 2.223 4.677 Will be offset. 



Miles per gallon of .i>asoline on pneumatic tires 5.77 5.75 7.21 7.70 x ^ nnccihio lr,cc rln,. to inlnr.r n^ tKhco r,l tli„ time \t Uts 



Miles per gall, n of gasoline on solid tires 3.98 4.77 5.43 7.10 -^^ ^° poSSlUle loss (lUC to injury or abuse ot tile tires, it ha! 



Miles per gallon of cH on pneiim.iiic tires — 104.00 32.00 55.00 152.00 been found that this is not a serious objection. There are many 



Miles per Ballon of oil on solid lives 59.00 30.70 54.00 78.00 . , . , . , , ,.,„„., 



Cost per mile on pneumatic tires cents 45.00 31.30 21.50 27.70 instances where pneumatic truck tires have run from 12,000 to 



Cost per mile on solid tires cents 56.30 55.00 24.00 31.00 



^ .\bstractcd from Cleveland-Detroit Sections paper, The Journal o'f the 



■ With a 2-ton truck for a 9-inonth period, a fifth operator obtained 9.1 Society of .\utomotivc Engineers, October, 1920. 



cniles per gallon of gasoline on pneumatic, and 6.1 miles per gallon on solid 2 Development engineer. The Goodyear Tire & Rubber Co.. Akron, 



lires. Ohio. 



