EXPERIMENT STATION BULLETINS 193 



DRAFT OF FARM IMPLEMENTS. 



BY M. W. FULTON. 



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Bulletin 165 — Farm Department. 



These tests began in 1895. A self recording dynamometer made by Aultman, 

 Miller tfc Co., of Akron, Oliio, was used. All tests were of one minute duration and 

 the distance traveled varied little in the different trials. The avei'age draft for each 

 trial was determined from the curve made by the recording pencil, by a planimeter, 

 which gave the average height of the curve above the base line. 



DRAFT OF WIDE AND NARROW TIRES. 



Tavo wagons were used in these trials. The tires of one were one and five-eighths 

 inches wide, of the other four inches. The diameter of the wheels was the same 

 for both wagons. The front wheels were forty inches high and the hind wheels 

 four feet. A uniform load, including wagon, of four thousand five hundred pounds 

 was adopted. 



The first trial was made on a gravel road, firm and dry. The draft of the narrow 

 tire was 151 pounds and of the wide tire 141 pounds, a diffei'ence of ten pounds in 

 favor of the wide tires. This agrees with the Missouri experiments which will be 

 referred to later in the bulletin, but is directly opposed to the popular opinion. 



Next on a sandy road, upon wliich the soft sand two inches deep rested upon a 

 subsurface not smooth nor hard, the draft of a wagon with narrow tires was ^63 

 pounds, with wide tires 217 pounds, a difference of 46 pounds in favor of the wide 

 tires. It so happens unfortunately that there are several miles of road of this sandy 

 character in the State and it is interesting to note that where the gross weight of 

 the wagon and load is 4,500 pounds it is drawn more easily upon wide tires than 

 upon narro^u ones. 



Tiie next trial to be reported took place upon a stiff June grass sod about the 

 middle of October, with, of course, the same load as in all other trials, viz., 4,500 

 pounds including wagon. Upon the sod, the draft of the wagon with narrow tires 

 was 334 pounds, that of the wagon with wide tires, 256 pounds, a difference of 78 

 pounds, or 23.35 per cent, in favor of the wide tires. The next day upon a clover and 

 timothy sod the narrow tires cut in two inches deep under the heavy load and thn 

 draft of the wagon was -590 pounds, while the wagon with the wide tires cut in but 

 one inch and the pull was but 4.30 pounds, 160 pounds, or 27.11 per cent, lesb than 

 the power required to draw the narrow tires. 



On the same day a trial was luade on corn stubble, driving between the rows. The 

 narrow tires sank in two and one-half inches, requiring a pull of 731 pounds to 

 move them; the same load upon the wide tires moved at a pull of 491 pounds, sinking 

 in but one inch. Here was a difference in draft of 240 pounds, or 32.83 per cent— 

 almost one-third less than with the narrow tires. 



These results all favor to a very marked degree, the wide tires. While upon the 

 gravel road, hard, smooth and well packed, the difference in draft is but 6.62 per 

 cent, using the narrow tire as a basis, upon sod or raw ground the difference is so 

 marked as to be decisive. 



The Missouri Station has conducted elaborate trials, comparing wide and narrow 

 tires, using a self-recording dynamometer as in our tests and with a net load of 

 2,000 pounds. The wide tires were six inches wide and the narrow ones one and 



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