THE INDIA RUBBER WORLD 



ccordance with this 



. _, of the straifiht side type. dcsi( 



light side 

 i. Construction, (a) Carcass ot tire shall consist ot _ no less tnan 

 four and no more than sixteen separate plies of cord applied in such a 

 manner that an equal ni-.mber of plies shall run in each diagonal direction 

 across the tire. 



(b) All cord material to be of the best quality combed Sea Island or 

 Egyptian cotton or its physical equivalent. 



(c) All cord fabric must be thoroughly dried according to standard 

 manufacturing practice, before it is started through the operations of 



(d) The usual methods of inspection used by tire companies in com- 

 mercial practice to discover defects in each roll of cord fabric shall be enj- 

 ployed, and tests to determine the tensile strength of cords shall be made 

 on ten individual cords taken from each roll. These tests shall be made in 



'rC "mlilhmTcoi.U s!..ill I,c listed in a fabric testing machine in which 

 i)u' 'tisLinre het\MtTi i^ripy is :tpjinviiTiatelv 10 inches, which grips separate 

 :n tl;.- rale of JO uifh, s iir ininuli-. The' results shown must be up to the 

 sl.iii.l:ird spccificatit n nf tlic imliviiiual manufacturer. 



u) lleaiis shall be constri;cled with wire strands in the same manner 

 as in standard commercial ijractice. Tensile strength tests for wire strands 

 ;i^ used by the individual tire manufacturers in the construction of beads 

 will he satisfactory in so far as they arc sufficient to preclude any chance of 

 a lit-ad stretching'or blowing off the rim when under pressure. 



tfi Two chafing strips of fabric weiKhing not less than 12 ounces per 

 square yard, shall be used. Each chafinK strip must extend upward on each 

 side of the tire, at least 2 inches from the licel of the bead. One chafing 

 strip shall extend at least !;J-inch above the other. 



(p) There shall be a cushion of rubber compound applied over the cords 

 which shall be wider than the breaker. The minimum gage of this cushion 

 shall be .090-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 

 properties 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 6J4 inches and shall be cut on a 45-deKree bias. Breaker shall be 

 made from the best quality Sea Island or Egyptian cotton or its physical 

 equivalent, and shall not weigh less than 10 ounces per square yard. 



(i) The tread of the tire shall not be less than 11/16-inch thick. Ji-inch 

 nf which shall be the minimum thickness for the part of the tread under the 

 middle of the non-skid portion. 



(j) The sidewall of the tire shall have a minimum thickness of .0625-inch. 



4. Physicai. Measurements and Tests, (a) Cross sectional diameter 

 if each tire inflated according to the recommended weight and load 

 -eheilule of the S. A. E. shall not be less than 8.2S-inch. 



1 10 Tire shall be capable of withstanding water prcssuie of 350 pounds 

 irr square inch without apparent injury. This test to be made at the 



' (Vf '"tIi" minitl^um strength of the tire shall be 4.00O pounds. This 

 ■strength factor" is the product of the number of cords per iiich measured 

 ' " ngth of individual cord 



U' cord t 

 ngth of 



betM 





the 



andar 



e) Strength of the union between sidewall and plies shall average 

 14 pounds or more per inch, using the standard friction test. 



(f) Strength of union between cushion and plies shall average 16 pounds 

 or more per inch, using the standard friction test. 



5. Road Test. Any manufacturer bidding on orders for government 

 business must he prepared to meet the following testing conditions: 



(1) No tires are to be given consideration bv the Government unless 

 the companv submitting the bid tenders an affidavit stating that they main- 

 tain and properly check up tests on cars to properly test their pneumatic 

 tire product and that these cars deliver an average of 8.000 tire miles 

 weekly. 



(2) The cars, speeds, loads and road conditions must be such that 

 the tires are properly tested and the Government may appoint an inspector 

 to see that the above conditions are complied with. 



(3) A successful bidder must supply an affidavit before delivering any 

 tires to the Government stating that the tires to be delivered are practically 

 duplicates in construction and material of tires which he has previously 

 tested properly and a sufficient number of tires, satisfactory to the Motor 

 Transport Ser 



aged 



eels at 



iles. 



Iiall be properly lined in accord- 



9. Inspection. The Motor Transport Service reserves the right to 

 make any inspection test, or analysis necessary to insure the product meet- 

 ing all requirements of this specification. 



10. Packing. All tires shall be spirally wrapped according to stand- 

 ard practice and properly labeled on the outside sliowing size, type, and 

 name of manufacturer, and marked with either tag or label in colors of 

 red, white or blue, which will denote as follows: red, first four months 

 of calendar year; white, second four months of calendar year; blue, last 

 four months of calendar year — years to be designated by square, tri- 

 angle and round labels or tags, — tags or labels to be approximately 2 inches 

 in diameter. Tires shipped for original equipment of cars shall be packed 

 as specified by customer. In the case of oversea shipments, the specifica- 

 tions covering this shall be applied. 



specifications for pneumatic tire inner tubes. 



Speciiication No. 1062. 



1. General. This specification covers the following sizes: 



(a) 26 by 3, 28 by 3, 29 by I'A, 30 by 3%, 33 by 4, 35 by 5, 36 by 6, 

 38 by 7, 40 by 8. 



(b) All tubes manufactured to this specification shall be of the endless 

 type except motorcycle tubes which shall be butt end or endless. 



(c) All tubes shall be free from defects and guaranteed as to material 

 and workmanship. 



2. Color. The color of the tubes shall be left to the discretion of the 

 manufacturer to use that which has been generally used by the individual 

 manufacturer with the best results in standard commercial practice. 



3. Compound, (a) Tubes shall be made from and have the character- 

 istics of a compound containing a minimum of 90 per cent by volume of 

 the best quality new wild or plantation Hevea rubber. Sulphur content 

 shall not exceed 7 per cent by weight of new rubber used. 



(b) The total organic acetone extract of the cured compound shall not 

 exceed 4J4 per cent by weight of the rubber used. 



(c) The total sulphur shall not exceed 7 per cent of the weight of 

 rubber used, except as follows: if the manufacturer desires to use sulphur 

 bearing mineral filler.?, thereby causing the total sulphur to be over 7 per 

 cent of the weight of rubber, he may do .so, but shall submit for analysis 

 a sample of the finished unvulcanized stock. Such stock shall not show a 

 sulphur content in the acetone extract of over 7 per cent of the weight of 

 new rubber used. 



(d) The filling material shall consist exclusively of dry mineral matter 

 of which not more than 6 per cent oi the total weight of the compound 

 shall be calciuni sulphate and in no case shall the calcium sulphate exceed 

 75 per cent of the weight of the antitaony present, the total antimony 

 being calculated to antimony pentasulphidi 



The inside of each 

 ance with the standard practice of tire manutacturers. 



7 r'LAPS. A flap of the size 40 by 8 shall be furnished with each tire, 

 as in standard commercial practice. 



8. Compounds, (a) The tread shall be made from and have the char- 

 acteristics of a compound containing at least 70 per cent by volume of the 

 best new rubber. Content of sulphur shall not exceed 8 per cent by weight 

 of the new rubber used. Compound shall contain no reclaimed rubber. 

 Minimum tensile strength of tread rubber shall be 2,700 pounds per square 

 inch and shall have a minimum set of 25 per cent. Set tests shall be 

 made by stretching 2 inches to 10 inches, and holding for 10 minutes. 

 Rest sample for 10 minutes and then measure the per cent of elongation 

 over the original length. . _ 



(b) Friction and Cushion.-— These shall be made from and have the 

 characteristics of a compound containing at least 85 per cent by volume 

 of the best quality new wild or plantation rubber. Sulphur content shall 

 not be more than 8 per cent by weight of new rubber used. No reclaimed 

 rubber shall be used. 



(c) Sidewall.— The sidewall shall be made from and have the charac- 

 teristics of a compound containing a minimum of 65 per cent by volume 

 of the best qualitv new wild or plantation rubber. Sulphur content shall 

 not be more than 8 per cent of weight of new rubber used. No reclaimed 

 rubber can be used. Compound shall have a minimum tensile strength of 

 1,800 pounds per square inch and a minimum elongation of 450 per cent 



(2 to 11 inches), and a maximum set of 25 per cent. The compound shall 

 be free of ingredients known to the rubber trade as "oil substitutes." 



(d) The total sulphur in any of the above compounds shall not exceed 

 8 per cent of the weight of new rubber used except as follows: if the 

 manufacturer desires to use sulphur-bearing mineral fillers, thereby caus- 

 ing the total sulphur to be over 8 per cent of the weight of new rubber, 

 he may do so, but shall submit for analysis a sample of the finished un- 

 vulcanized stock. Such stock shall not show a sulphur content in the 

 acetone extract of over 8 per cent of the weight of new rubber used. 



Tubes 



fill 



Gages. 

 table for minimum curii 

 Size. 

 26 by 3 



28 by 3 



29 by S'A 



30 by iVi 

 33 by 4 



35 by 5 



36 by 6 

 38 by 7 

 40 by 8 



(b) In case tube is n 

 as determined by volumi 

 shall be at least equal 1 



5. Splice. The spli 

 inflation test. 



6. Valves. Each tube shall be fitted with one co 

 or its equal, applied in such a manner as not to 1 

 ordinary usage. The following schedule shall apply: 



If 



specifications in the following 



5ize ana minimum gages: 



[inimum Pole Size. Minimum Thickness. 



n^ inches .072 



IH inches .072 



2 inches .080 

 2H inches .085 

 2}i inches .095 



3 inches .125 

 3^ inches .155 

 4'A inches .175 

 4)i inches .195 



;d measurements must be equivalent to above 

 fferent-sized poles are used volume of rubber 



shall be 



strong 



the 



Valv 



26 by 3 



28 bv 3 Valvi 



29 by iVi Valves si 



30 by 3J4 Valves si 

 33 by 4 Valves si 



35 by 5 Valves si 



36 bv 6 Valves similar to 

 38 by 7 Valves similar to 

 40 by S Valves similar to 



Each valve shall be fitted o 



Schrader 

 lar to Schrader's 

 lar to Schrader's 

 lar to Schrader*£ 

 lar to Schrader's 

 lar to Schrader's 

 lar to Sch ■ ■ 



of the tube under 



1936 



1936 



725 or No. 967 

 725 or No. 967 



Schr 



ader' 



No. 2033 

 No. 2033 

 No. 2033 



vlth lock 



nut, valv 



ap sh.- 



6 and 



Spreade 



tlon^of 

 for all 



»6 by 3, 28 by I'A, 36 bv 



sizes up to and including 35 by 5. . 



7 Marking. These tubes shall be plainly marked with the manufac- 

 turer's name and size of tube, in both inch and the millimeter equivalent 

 ill accordance with S. A. E. standards._ 



8. Tests and Inspection. (a) 

 made from each 



shall 



accordan 



requirements 



of 



,..^..^= « quality and - 



this specification. For physical tests cut from tube specimen in the torm 



of the standard shape for rubber test samples. The center of the sample 



shall be '4 -inch in width. The thickness shall be the full thickne 



the tube' and the length shall be 1-inch. The average o.f.te: 



specimens cut longitudinally from each lot shall show a minimi 



tion of 750 per cent (1 inch to 8;; inches), and a permanent 



more than 10 per cent. The per cent of permanent set will 



mined by stretching test piece 500 per cent (1 inch to 6 inches) 



at this point for 10 minutes followed by 10 minutes' rest and 



uring the per cent of elongation of test piece over the ong 



length. This percentage shall be called the per cent ot permanent set ot 



the specimen. Minimum tensile strength of tubes shall be 1,600 pounds 







inch. 



The 





ight 



neeting 



r Transport 

 spection. test, or analysis neci 

 quirements of the specification 



9. Packing. All tubes shall be wrapped and packed in an adequate 

 pasteboard carton, such as is usually used by the manufacturer producing 

 the tubes. The boxes shall be plainly marked with the manufacturer's 

 name and the size of the tube and marked with either tag or label in 

 colors of red, white or blue, which will denote as follows: red, first four 

 months of calendar year; white, second four months of calendar year; 

 blue, last four months of calendar year. Years to be designated by square, 

 triangle and round labels or tags. Tags or labels to be approximately 2 

 inches in diameter. 



