January 1, 1919.] 



THE INDIA RUBBER WORLD 



Government Specifications for Tires, Tubes, Repair Materials 



and Accessories. 



THE Motor Transport Corps of the United Stales Army, the 

 War Service Committee of the Rubber Industry, and the 

 Special Board of Officers, convened under paragraph 30, 

 S. O. 91, W. D., 1918, have prepared and approved the following 

 specifications for pneumatic tires, including automobile, motor- 

 cycle and bicycle tires ; solid motor tires, repair material and 

 accessories. These specifications were revised to November 1, 

 and supersede those published in The India Rubber World Octo- 

 ber 1, 1918. 



CLINCHER BICYCLE TIRES. 



Sizes 28 by 1^< inches and 28 by \5^ inches. 

 fabric construction. 



Specification No. 1221A. 

 November 1, 1918. 

 1. General, (a) Bicycle pneumatic casings manufactured in accord- 

 ance with this specification shall be of fabric or cord construction of the 

 sizes known as 28 by 1 H inches and 28 by 1 5^ inches. 



(b) The manufacturer of casings must guarantee them to be free from 

 defects in workmanship and material. 



(c) The casings shall be plainly marked with the manufacturer's name 



of 



All 



nufacturer's standard non-skid double clincher type, designed to satis- 

 factorily fit the standard 28 by I'i inches single clinch all steel bicycle rim. 



3. Construction, (a) Carcass of the casings must consist of two 

 plies of fabric frictioned both sides. 



(b) All fabric shall be square-woven (26 by 26) having a tensile 

 strength for both warp and filler of not less than 110 pounds per inch 

 or its physical equivalent of cords as approved by the Government. Methods 

 to be the same as provided in the specifications for pneumatic 



of testing to be 



the 



■asmg. 



; AND Tests, (a) The cross-sectional di- 



, 40 pounds shall not be less than 1-29/64 



1-37/64 inches in 28 by 1 ^ inches. 



between piles of fabric shall average ten 

 g the standard dead weight friction test as 

 5r pneumatic automobile casings, 

 inion between tread and plies or between 

 nore using the standard 



rdance with the standard 



when measured on the 



4. Physical Measui 

 ametcr of each tire ilif 

 inches in 28 by 1 }-< inc 



(b) Strength of the 

 pounds or more per ini 

 provided in the specific; 



(c) The strength o 

 sidewall and plies shall average nme pounc 

 dead weight friction test as above provided. 



5. Flaps. Each casing shall have a flap i 

 commercial practice. 



6. Compounds, (a) Tread. — The tread shall be made from and have 

 the characteristics of a compound containing at least 55 per cent by volume 

 of the best quality new wild or plantation rubber. The minimum tensile 

 strength shall be 1,600 pounds per spuare inch with a minimum elongation 

 of 400 per cent (2 to 10 inches) as determined by the average of four 

 test pieces when stretched at the rate of twenty inches per minute. The 

 test pieces shall be cut longitudinally and shall be ;4-inch wide of a gage 

 length of two inches, the ends being gradually enlarged to a width of 

 approximately one inch. The permanent set determined by the average 

 of four tests with test pieces as above, shall not exceed 25 per cent after 

 an elongation of 400 per cent (2 to 10 inches) for ten minutes. All tests 

 shall be made at a temperature between 65 degrees and 90 degrees F. 



(b) Friction.— The friction shall be made from and have the character- 

 istics of a compound containing at least 65 per cent by volume of the best 

 quality new wild or plantation rubber. 



(c) Sidewalls.— The sidewalls shall be made fn 

 acteristics of a compound containing at least 55 per 

 best quality new wild or nlantatiou rubber. The m 

 of the sidewall rubber shall be 1,200 pounds p< 

 minimum elongation of 400 per cent (2 to 10 in 



nd hav 



eed 



del 



redients known to the rut 

 .1st stale the amount and kind of reclaii 



erage of four tests as described in 6(a). 



(d) Compounds shall be free frcm i 

 trade as oil sub.stitute; 



(e) The manufact 

 rubber used in all compounds. 



(f) All above test pieces must be cut from casings. 



7. Inspection. The Government reserves the right to make any m- 

 speclion, test or nnalysis necessary to insure the product meeting all 

 requirements of this specification. 



8 Tubes The inner tube shall meet the specifications of the auto- 

 mobile and motorcycle tubes, with the following exceptions: (a) minimum 

 pole size shall be 1-inch; (b) minimum gage shall be 0.048-inch; (c) the 

 valve shall be Schrader's 1022. or its approved equivale 

 9. Packing. Packing shall be as per specification 

 request for bid. 



PNEUMATIC MOTORCYCLE CASINGS (NON-SKID). 

 Size 28 by 3 inches. 

 fabric construction. 



Specification No. 1064A. 



XOVEMIIER 1, 1918. 



1. General, (a) Pneumatic motorcycle casings manuf.ictured ii 

 cordance with this specification shall be of fabric construction of th< 

 iknown to the trade as 28 by 3 inches. 



npanying the 



The 



40 



defects in materi,;! :,n.l v,..,k, 



(d) Casings shall U |a..i 

 number and size cf lire. 



(e) As soon as possible 

 the equivalent metric sizes a 





ill casings manufactured in accordance with this specifica- 

 tion shall be of the manufacturer's standard non-skid clincher type, de- 

 signed for the S. A. E. clincher motorcycle CC rim of the size 28 by 3 



3 Construction (a) Splices on the first ply of fabric shall be gum- 



(h1 t H f f ur separate plies of tire fabric. 



iide. 



Ci by 23) from Egyptian long- 

 as approved by the Government, 

 rd with an allowable variance of 



the warp strength and three samples shall be cut transversely to determine 

 the filler strength. The samples shall be prepared in the following manner: 

 unravel to 23 yarns (1-inch width); fabric shall be dried one hour and 

 thirty minutes at 110 degrees C. Breaking test shall be completed within 

 thirty seconds of time of removing test strip from oven. The results must 

 show a tensile strength of not less than 165 pounds per inch width for 

 either warp or filler. 



(f) Beads shall be constructed with a core filler as in standard com- 

 mercial practice. 



(g) There shall be a cv 

 fabric which shall be wider 

 cushion shall be 0.0325-inch. 



(h) Over the cushion there shall be at least one breaker strip of open- 

 weave fabric such as is used in standard commercial practice, coated on 

 both sides with a rubber compound having the physical and chemical proper- 

 ties of a nature to form a perfect union between the cushion and tread 

 when the cure is effected. This breaker strip shall have a minimum width 

 of IH inches. Breaker shall be made from long-staple cotton weighing not 

 less than 8 ounces per square vard. 



(i) The tread of the casing shall not be less than ■i-incli thick in the 

 center, H-inch of which shall be the minimum thickness for that part of 

 the tread under the middle of the non-skid portion. 



(j) The sidewall of the casitig shall have a minimum thickness of 0.045- 



4. Fny 

 of the S. 



\L MEASUREMENTS AND Te.sts. (a) Crossscctional diameter 

 iflated according to the recommended weight and load schedule 

 E. shall not be less than 2-15/16 inches nor more than 3-3/10 



erage 

 ialfy" 



the standard practu 



the breaker and tread and between 



less than 28 pounds per inch using 



above provided. 



iless the maker submitting 

 maintained and will con- 

 exclusively for test work, 

 1,000 machine miles per 



be properly lined in a 



lufacturers. 



mented inside of the 



