88 



THE INDIA RUBBER WORLD 



November 1, 1920 



T.\BI.E II. 



Year 



1919 

 April . . . . 

 May .... 



Jane 

 «ly 



.August . . . 

 September. 



Totals . . 



Average 



Through Overhead 



Trucks Total Loading Cost Tola! 



Actively Fleet Ton- Capacity Operating Cleveland Operating 



Operated Mileage Mileage Per Cent Cost Terminal Cost 



WiNCFOOT Highway Express 



Cost 



$5,743.31 

 6,594.32 

 6,131.35 

 5,935.57 

 6,175.55 

 5,802.54 



Per 

 Per Mile Ton-Mile 

 $0.42170 $0.15670 

 0.39620 0.15590 

 0.42590 0.17150 

 0.41690 0.15760 

 0.40600 0.15345 

 0.33603 O.12940 



Pay Loads 

 Hauled, lb. 

 1,450,704 

 1,864,235 

 1,674,669 

 1,733,570 

 1,684,181 

 2,083,383 



Revenue 

 $6,522.32 

 7,962.70 

 7,099.30 

 7,620.46 

 7.331.67 

 9,371.69 



Profit 

 $779.01 

 1,368.38 

 967.95 

 1,684.89 

 1,156.12 

 3,569.15 



Truck Efficiency 

 Miles per Gal, 



' ^ — ;r^ 



Gasoline Oil 



81,706 212,283 



$32,530.33 $3,852.31 



7.7 13,617 35.381 80 $5,421.72 $642.05 



$36,38:.64 

 $6,063.77 



10,490.742 $45,908.14' $9,525.50 



$0.40045 $0.15409 1,748,457 $7,651.35 $1,587.58 5.93 143.3 



'Gross earnings. 51.9 per cent on the investment, 26.2 per cent on the operating cost. 



Operating costs and efficienc>- of solid and pneumatic tire equip- 

 ment are -rompared in the following tabulation : 



T.\BLE III. Solid versus Pneumatic Tire Equipment 



Details 



Type, tons 



Total travel, miles 



Number of round trips 



Average mileage per trip 



Hauling, ton-miles . -. 



Loading capacity throughout, per cent. 

 Costs 



C^soline 



Oil 



Drivers 



Administration 



Depreciation 



Maintenance, material 



Maintenance, labor 



Consumer's tire cost 



Miscellaneous 



Interest 



Insurance 



Rent 



Total operating cost 



Efficiency^ 



Cost per mile 



Cost per ton-mile 



Gasoline, miles per gallon 



Oil, miles per gallon 



Time per round trip, hours 



Truck speed, m. p. h 



Time saved, hours 



Driver's earnings — 



Straight time 57.8 hours, at $0.60 



Overtime 57.8 hours, at $0.90 



Saving on ton-mile cost 



Net saving effected 



Ket gain by cost reduction, per cent 



" Credit not allowed pneumatic-tired equipment for additional available 

 hours over solid tires; increased satisfaction and better personnel of drivers, 

 with less labor turn over, value to production in effecting quicker deliveries, 

 additional safety and fewer claims for breakage in pay loads. 



POINTS FROM THE DISCUSSION OF PNEUMATIC VS. SOLID 

 TRUCK TIRES 



J. E. Schipper:— On the large-size tires there is considerable 

 more ci a flat tread than on the smaller sizes; that is, the sidevvall 

 seems to be built up. Would that work out to advantage in the 

 smaller-size tires, and has it any effect on the gas consumption 

 on rutty roads? 



Chairman Hai.e:— There is a flat tread and steep sidewall on 

 the 44 by 10 and 48 by 12-inch tires. In 1917 it was decided that 

 we should make a 44 by 10-inch pneumatic truck tire with suffi- 

 cient carrying capacity to support a 3-ton truck. The greatest 

 difficulty encountered was to prevent separation between the tread 

 and the carcass. The first tires were made with round treads, 

 which caused the tires to flex considerably before the necessary 

 contact area could be obtained. This flexing, combined with a 

 component of the vertical load on the tire, resulted in a tremen- 

 dous shearing action between the tread and carcass, which in time 

 caused the tread to separate from the carcass or tire body. The 

 logical thing was to make the tread flat, to give the necessary 

 contact area without so much flexing and to widen it t ut, which 

 would decrease the unit stress on the union between the treac 

 and carcass of the tire. We did that and the results have been 

 very satisfactory, 



There seems to have been an understanding among tire design- 

 ers that it is not good practice to have much of a shoulder at 



the edge of the tread of passenger-car tires. However, we have 

 proved that a flat tread of the proper proportions has several 

 distinct advantages and results in much longer tire life. As to 

 the relative economy in gasoline consumption of the two types 

 of tire on rutty roads, there would be a slight advantage in favor 

 of the round tread ; but when good roads are taken into considera- 

 tion the advantage would be in favor of the flat tread. 



Have any tests been made to determine what the trucks geared 

 to run 30 m.p.h. with a larse engine will do in city travel? Is 

 this truck limited to one particular use? 



Gasoline and oil consumption comparisons hardly seem fair. 

 The pneumatic records have been made on trucks with tires which 

 have been developed for this purpose. The commercial solid tire 

 has been made to sell. The efficiency varies tremendously. That 

 may possibly be due to variations in tire manufacture. The tires 

 used on electric trucks have to' be made of an entirely different 

 compound. So far as we have been able to determine, the highly 

 efficient solid tire does not give any reduced mileage. Under 

 equal conditions it gives better mileage. There is also a possibility 

 for the development of the solid tire. We have run a few S.K.' 

 tires and have had remarkable results. That tire has great pos- 

 sibilities for city work. 



In connection with pneumatic tires, the demand comes from 

 people who want to put these tires out in the country where there 

 are no good roads. They buy them because they cannot get 

 there with the solid tires. But they soon find that operating 

 trucks under those conditions is hard on the truck tires, engine 

 and every other part of the chassis and body. That immediately 

 brings about a demand for a good road, with a foundation and 

 with good surface. With the ultimate road of that type, what 

 sort of tire will be used? The trend toward the pneumatic tire 

 may change in time because of the changed condition of the road 

 surface. The locomotive with its steel track and steel wheels gets 

 satisfactory running under most conditions. It will be a long 

 time before we have the type of road which the railroad now has, 

 but the smooth hard road appears to be the ultimate road. If 

 that is the case, would not the solid tire serve well? 



Mr. Scott :— Regarding the 30-m.p.h. truck designed for pneu- 

 matic tires, its efficiency and the speed at which it must run in 

 city streets, this is a question of the efficiency of the large engine 

 in comparison with the small. Practically all of our experimental 

 work has been over long runs. By usin;j a S-ton truck engine to 

 draw a 3-ton load we found that this engine was more economical 

 than that of the 354-ton truck. This is because of the ease with 

 which the large engine does the work. Over the mountains the 

 smaller engine was working at a maximum. A very close check 

 on that showed a 0.7-mile difference in gasoline consumption of 

 the larger engine over the smaller. 



City work is dependent upon the stops to be made. Many 

 trucks stop often ; with these we can get about two miles per gal- 

 lon of gasoline. With that same truck outside of the city, we 

 can get six miles per gallon. An average on all the buses shows 

 about five miles per gallon of gasoline with a 2-ton chassis. But 

 that is not low mileage, because of the unusual number of starts 

 and stops. 



* Goodyear cusliion tire. 



