THE INDIA RUBBER WORLD 



test to be made 



Tires shall be capable of witbstandinp; \ 

 uare inch without apparent injury. Thi^ 

 of the inspector. 

 Strensth of the union between plies of fabric shall 

 Ills ur more per inch, using the standard friction test. 



veragc 18 



Strength 

 breaker and cushion shall 

 standard fri'ction test. 



(c) Strength of the union between sidewall and plies shall average 10 

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



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

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



5. Road Test, (a) Any manufacturer, bidding on orders for govern- 

 ment business, must be prepared to meet the following testing conditions: 



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

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

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

 tire products 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 ihat the above conditions are complied with. 



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

 tirus 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 Service, at least six tires, have averaged on the rear wheels at 

 least 4,000 miles. 



6. Lining. The inside of each tire shall be properly lined in accord- 

 ance with the standard practice of tire manufacturer. 



7. Flaps. No flaps shall be supplied. 



S. Compound, (a) Tread — The tread shall be made from and have 

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

 of the best quality of new wild or plantation rubber. Content of sulphur 

 shall not exceed 8 per cent by weight of new rubber used. The compound 

 shall be free from ingredients known to the rubber trade as "oil substi- 

 tute." Minimum tensile strength of tread rubber shall be 2.600 pounds 

 per *i|uare inch and shall have a maximum of 25 per cent (400 per cent 

 ol 2 to 10 inches when elongated for 10 minutes, using a sample with 10 

 minutes' rest before measuring). 



(hi Friction and Cushion — These shall be made from and have the 

 characteristics of a compound containing at least 75 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. 



(c> Sidewalls. The sidewalls shall be made from and have the character- 

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

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

 not be more than 8 per cent by weight of new rubber used. Reclaimed 

 rubber to the extent of 15 per cent by weight of total compound is allow- 

 able but the amount and kind must be declared by the manufacturer. 

 Compound shall have a minimum tensile strength of 1,500 pounds per 

 square inch and a minimum elongation of 450 per cent (2 to II inches) 

 and a maximum set of 25 per cent. The compound shall be free from 

 inizredients known to the rubber trade as "oil substitutes." 



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 manufac- 

 turer desires to use sulphur bearing mineral fillers, thereby causing 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 unvulcanized 

 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. 



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 standard 

 ■practice and properly labeled on the outside showing 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, triangle and round 

 labels c- taes, tags or labels to be apprr-^—- ■'- ■< — •— ■" -i-™-" 

 Tires shipped for original equipment of c; 

 by customer. In the case of oversea shipn 

 this shall be applied. 



SPECIFICATIONS FOR PNEUMATIC AUTOMOBILE TIRE 

 CASINGS, SIZE 33 BY 4. 



Specification No. 1067. 

 fabric constkuction. 



1. General, (a) Pneumatic automo 

 accordance with this specification shall h 

 known to the trade as 33 by 4. 



tb) The tire must give satisfactory si 

 when inflated to 65 pounds per square ii 



icl Tire to be free from all defects 

 rial and workmanship. 



nd fully guar; 



struction of the size 

 load of 815 pounds 

 iteed as to mate- 



design of the 



of the 



shall 

 nd the 



be of the standard commercial 

 ufaclurer furnishing the same. In the case oi 

 than one non-skid design, selection of the design to be adopted 

 option of the Motor Transport Service. A small secti— -' •'" 

 be submitted for approval before contract is let.i 



(e) The tires shall be plainly marked with manufact- 

 size of the tire, and marked with either tag or label in colors of red, ™....^ 

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

 vear- vJhite, 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 



(f) As soon as possible it is desired that all tires be marked with the 

 equivalent millimeter sizes as recommended by the Society of Automotive 

 Engineers. , . , , . -.^ .- 



' TvpE .Ml tites manufactured m accordance with this specihcation 

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

 side rim of the size 32 by 3}^ or 33 by 4 new standard rim. 



3 Construction, (a) Splices on the first ply of fabri'c shall be gum 



on one side applied on a 45-degrce bias. The gage of one ply frictioued on 

 two sides and skim-coated on one shall be at least .04S-inch. Each ply 

 shall have not more than two splices which must be at least 7 inches apart 

 measured on the circumference of the tire. The splices in the tire shall 

 be at least 3 inches apart when measured on the circumference of the tire. 



(c) All fabric must be square woven (23 by 23) from the best quality 

 Sea Island or Egyptian long staple cotton or its physical equivalent weigh- 

 ing 17>4 ounces to the square yard with an allowable variance of plus or 



(d) All fabric must be thoroughly dried according to standard manufac- 

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



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

 mercial practice to discover defects in each roll of fabric shall be employed. 

 The following tests shall be used to determine the strength of the fabric. 

 .Ml fabric shall be tested in a standard testing machine to determine the 

 tensile strength. The distance between the grips on the machine shall be 

 approximately 3 inches and the separation of the jaws shall be at the rate 

 of 20 iuches per minute. Six samples shall be cut from each roll in such 

 a manner as to eliminate any unnccessarjr waste of material. Three sam- 

 ples shall be cut longitudinally to determine 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), heat until sample is "bone dry" and immediately test it in 

 machine. Tlie results must show a tensile strength of not less than 180 

 pounds per inch width for either warp or filler. 



(f) Beads shall be constructed with wire strands in the same manner as 

 in the standard commercial practice. Tensile strength tests for wire 

 strands as used by the individual tire manufacturers in the construction of 

 beads will be satisfactory in so far as they are sufficient to preclude any 



bead stretching or blowing otf the rini when under pressure. 



s than 8 



The chafing strip shall extend up- 

 ire at least 1 inch from the heel of the bead, 

 cushion of rubber compound applied over the 

 r than the breaker. The minimum gage of this 



ward on each side of the 



(h) There shall be a 

 fabric which shall be wide 

 cushion shall be .OSOinch. 



(i) 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 prop- 

 erties of a nature to form a perf'' " 



when the cure is effected. Thi 

 width of 2"^ inches. 



Breaker shall be made from i 

 cotton or its physical equivalent, 

 per square yard. 



(j) The tread of the tire shall not be less than J^-inch thick at the 

 center, i-a-inch of which shall be the minimum thickness for the part of the 

 tread under the middle of the non-skid portion. 



(k) The sidewall of the tire shall have a minimum thickness of .050- 



ND Tests, (a) Cross sectional diameter 

 the recommended weight and load sched- 

 ule of the S. A. E. shall be not less than 4 inches. 



(b) Tire shall be capable of withstanding water pressure of 300 pounds 

 per square inch without apparent injury. This test to be made at the dis- 

 cretion of the inspector. 



(,c; Strength of union between plies of fabric shall average 18 pounds 

 or more per inch, using the standard friction test. 



(d) The strength of the union between breaker and tread and between 

 breaker and cushion shall average 28 pounds or more per inch, using the 

 standard fi ' '' 



side 



ud plii 



pounds or more per inch, using the standard frictio 



(f) Strength of the union between cushion and pJies 



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

 5. Road Test. (.a). Any manufacturer, bidding or 



government business, must be prepared to meet the folio 



rage 10 



shall average 



orders for 1 

 ving testing ci 



on by the Government unless 

 ffidavit stating that they main- 

 properly test their pneumatic 

 I average of 8,000 tire miles 



(I) No tires are to be given consK 

 the company submitting the bid tenders 

 tain and properly check up tests on ca 

 tire product, and that these cars deliv 

 weekly. 



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

 t res are properly tested and the Government may appoint an inspector to 

 see that the above conditions are complied with. 



(.3) .\ 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 Service, at least six tires, have averaged on the rear wheels at 

 least 4.000 miles. 



6. Lining. The inside of each tire shall be properly lined in accord- 

 ance with the standard practice of tire manufacturers. 



7. Flaps. A flap of the size 33 by 4 shall be furnished with each tire, 

 as in standard commercial practice. 



8. CcMPOuNDS. (a) Tread — The tread shall be made from and have 

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

 of the best quality of new wild or plantation rubber. Content of sulphur 

 shall not exceed 8 per cent by weight of new rubber used. The com- 

 round shall be free from ingredients known to the rubber trade as "oil 

 substitutes." Minimum tensile strength of tread rubber shall be 2,000 

 pounds per square inch and shall have a maximum set of 25 per cent 

 (400 per cent or 2 to 10 inches when elongated for 10 minutes, using a 

 2-inch sample with 10 minutes' rest before measuring. 



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

 characteristics of a compound containing at least 75 per cent by volume 

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

 not be more than 8 per cent by weight of new rubber used. 



Inspector shall have the privilege of taking a suitable sample for chemical 

 analysis of the cushion stock and friction stock as it is just before being 

 built into tire. The manufacturer may, if he desires, vulcanize this sample 

 with a suitable cure before being sent out for test. 



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

 istics of a compound containing a minimum of 65 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. Reclaimed rubber 

 to the etxent of 15 per cent by weight of total compound is allowable, but 

 the amount and kind must be declared by the manufacturer. Compound 

 shall have a minimum tensile strength of 1,500 pounds per square inch 



