188 



THE INDIA RUBBER WORLD 



[January 1, 1919. 



year oi nianutacturc stamped on it shall be pasted in a conspicuous place. 

 U. Packing. Packing shall be as per specifications accompanying the 

 request for bid. 



PNEUMATIC AUTOMOBILE CASINGS (RIBBED OR NON-SKID). 



Size 38 by 7 inches, 

 cord construction. 



Specification No. I071A. 

 NOVEMDEK 1, 1918. 



1. Genehal. (a) Pneumatic automobile casings manufactured in accord- 

 ance with this specification shall be of cord construction, of the size known 

 to the trade as 38 by 7 inches. 



(b) Casings must be designed to carry a load of 2,700 pounds when 

 inflated to 100 pounds per squaie inch. 



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

 defects in material and workmanship. 



(d) Casings shall be plainly marked with manufacturer's name, serial 

 tiumber and size of tire. 



(e) As soon as possible, it is desired that all casings be marked with the 

 equivalent metric sizes as recommended by the Society of Automotive 

 Engineers. 



2. Type. All casings manufactured in accordance with this specification 

 shall be of the manufacturer's standard non-skid or ribbed (as ordered) 

 straight side type designed for the standard S. A. E. straight side nm ot 

 the size 38 by 7 inches. 



3 Co.NSTRUCTioN. (a) Carcass of casing shall consist of not less than 

 four nor more than fourteen separate plies of cord applied in such a manner 

 that an equal number of plies shall run in each diagonal direction across the 



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

 manufacturing practice before it is started through the operation ol 

 rubberizing. 



(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 

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

 on ten individual cords taken from each roll. The results shown must be 

 up to the standard specification of the individual manufacturer. 



(e) Two chafing strips of fabric weighing not less than twelve ouiices 

 per square yard, shall be used on each side of the cas.tig. , Each chafing 

 strip shall extend upward -' '■■- ^ '— '" '"'■''" f'"" 



ad shall be made from and have 

 containing at least 70 per cent by volume 

 of the best quality new wild or plantation rubber. The 

 strength shall be 2,400 pounds to the 



m tensile 

 pounds to the square inch, with a minimum elonga- 

 i.ui. if 500 per cent (2 to 12 inches) as determined by the average of 

 four test pieces when stretched at the rate of 30 inches per minute. 

 The test pieces shall be cut longitudinally and shall be J4inch wide over 

 a gage length of 2 inches, the ends being graduilly 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 ii per cent aiier 

 an elongation of 400 per cent (2 to 10 inches) for ten minutes, followed 

 by a rest of ten minutes. All tests shall be made at a temperature between 

 65 and 90 degrees F. 



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

 rharricteristics of a compound containing at least 8S per cent by volume 

 rif the best quality new wild or plantation rubber. 



(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 bc-t quality new wild or plantation rubber. The compound shall 

 'i.ive 'I minimum tensile strength of 1,500 pounds per square mch and a 

 minimum elongation of 450 per cent (2 to 11 inches). The permanent set 

 shall not exceed a maximum of 25 per cent, tested as specified in 8(a). 



the 



the right to make any 

 the product meeting all 



insure the product meeting 



gs shall be spirally wrapped ac- 

 " ■ ■ ' 'ide showing 



conspicuous 

 accompanying the 



d properly labeled 



lall be pasted 



ai..u =..o.. ^.^.^ V the side of the casing at least Wi inches 



the heel of the bead. One chafing strip shall extend at least ".^inch above 

 the other. 



(f) 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 O.OSO-inch. 



(b) 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 5^4 inches. Breaker shall be made from long-staple Egyptian cotton or 

 its physical equivalent as approved by the Government and shall weigh not 

 less than eighteen ounces per square yard. 



(M The tread of the casing shall not be less than H'inch thick in the 

 center li-inch of which shall be the mitiimum thickness for that part of 

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



(i) The sidewall of the casing shall have a minimum thickness of 

 0.062S-inch. . , j- 



4 Physical Measurements and Tests, (a) Cross-sectional diameter 

 of each "ire inflated according to the recommended weight and load schedule 

 of the S. A. E. shall be not less than 7.35 inches. 



■ (b) Tires shall be capable of withstanding water Pressure of 350 pounds 

 -per square inch without apparent injury. This test is to de made ai tiic 

 discretion of the inspector. 



fcl The minimum strength of the casing shall be 3,500 pounds. This 



individual cord as taken from the cord casing, multiplied by the numoer 

 '°*(dr'The strength of the union between breal<er and tread and between 



^^?d^"^t1?^it- "^t'af^d^ ?:^^^.Tf^ 



casing spe 



(e) Strength of the ui 

 pounds or morf; per 

 above provided. 



(f) Strength of the u 

 pounds or more per inch, 

 above provided. . 



5. Road Test. Manufacturers bidding on government requirements 

 must meet the following conditions: 



(a) Casings will not he given consideration unless the "/" ;"^!V'"'"f 



that these cars average at least 500 car miles per car oer weeK. 



(b) The speeds, loads (which may be of merchandise), ""sues in- 

 flations and road conditions must be such that the casings are properly 

 tested The Government may appoint an inspector to see that the above 

 .conditions are complied with. 



(c) A bidder must supply an affidavit before delivering any casings 

 to the Government stating that the cnsines to be delivered are the same 

 '.cross-section .ind practically duplicate, in construction and material, casings 



which he has previously tested in accordance with paragraphs (a) and (b) 

 ind a suflScient number of casings satisfactory to the Goveinment, not less 

 *&o four, have averaged on the rear wheels at least 5,000 miles. 



6. Lining. The inside of each casing shall be properly lined in ac- 

 cordance with the standard practice of lire manufacturer. 



7. Fl.aps. a flap shall be furnished with each casing, as in standard 

 fommercial practice. 



(d) All above test pieces must 1 



(e) The above compounds shall 

 rubhei trade ns oil substitutes and 



9. iNsrECTiON. The Governmer 

 spection, test or analysis necessary 

 iiuirements of this specification. 



10. Wrapping and M.^HKING. A 

 cording to standard practice 

 '.he size and type, and name of i 

 iind year of manufacture stamped 

 place. 



11. Packing. Packing shall be 

 request for bid. 



PNEUMATIC AUTOMOBILE CASINGS (RIBBED OR NON-SKID) 

 Size 40 by' 8 inches. 

 coed construction. 



Specification No. ID72A. 

 November 1, 1918. 



1. General, (a) Pneumatic automobile casings manufactured in ac- 

 cordance with this specification shall be of cord construction of the size 

 known to the trade as 40 bv 8 inches. 



(b) Casings must be designed to carry a load of 3,650 pounds when 

 inflated to 110 pounds per square inch. 



fc) Tl'e manufacturer of casings must guarantee them to be free from 

 defects in material and workmanship. 



Ml Casings shall be plainly marked with manufacturer's name, serial 



(e) As soon as possible 

 the equivalent metric sizes 

 Engineers. 



2. Tyff. All casings manufactured in accordance with this specification 

 shall be of the manufacturer's standard non-skid or ribbed (as ordered) 

 straight side type designed for the standard S. A. E. straight side rim of the 

 size 40 by 8 inches. 



3. CONSTRLCTION. (a) Carcass of casing shall consist of not less than 



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

 facturing practice before it is started through the operations of rubberizing. 



(dl The usual methods of inspection used by tire companies in commer- 

 cial practice to discover defects in each roll of cord fabric shall be employed, 

 ,ind tests to determine tensile strength of cords shall be made on ten 

 individual cords taken from each roll. The results shown must be up to the 

 5tand?rd speciPcation of the individual manufacturer. 



(e) Two chaftni; strips of fabric weighing not less than twelve ounces per 

 square yard, shall be used on each side of the casing. Each chafing strip 

 shall extend upward on the side of the casing at least two inches from the 

 heel of the bead. One chafing strip shall extend at least '/i-inch above the 



othe 



ff) Tli< 



all be 



jbber 



npou 



the 



cords which shall be wider than the bre.iker. The minimum gage of thil 

 cushion shall be 0.090-inch. 



(g) 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 cushii 



tread when the 

 idth of 6^ ii 



effected. Thii 



shall weiiih not less than r 

 The tread of the i 



aker shall 



reake 



shall 



fron 



approved by the 



the center. 



inch of 



ng shall nc 

 h shall he 

 liddle of th( 

 :asing shall 



be less than 



the 



i-skid po 



thic 



part of the 



(i) The sidewall of the cas 

 0.0625-inch. 



4. Physical Measurements 

 of each tire inflated according 

 schedule of the S. A. E. shall be not le.s's than 



(b) Tires shall be capable of withstanding \ 

 per square inch without apparent injury. Th 

 discretion of the inspector. 



(c) The minimum strength of the casing shall be 4,000 pounds. This 

 "strength factor" is the product of the number of cords per inch measured 



■ight a_ngles_ to the cords, multiplied by the strength of 

 " e cord casing, multiplied by the number 



Tests, (a) Cross-s 



thickness 



ii 350 pounds 



the tn 



of pli, 

 (i) 



'idual cord 



taken 



The 



ength of the union between 

 ishion shall be not less than 

 weight friction test as provit 



ker and tread and between 

 pounds per inch using the 

 in paragraph No. 4, fabric 



