THE INDIA RUBBER WORLD 



shall be pla 

 of the tire, 

 blue, which 



and round labels or 



(f) As soon as p 

 equivalent millimeter 



orcycle CC rim of the 



ked with either tag or label in colors 

 )te as follows: red, tirst four months 

 months of calendar year; blue, last 

 to be designated by square, triangle 

 be approximately two inches in 



r labeli 

 desired that 



28 



ith the 



Clincher 



Splices on first ply fabric shall be gum stripped. 



(b) Carcass of tire shall consist of at least four separate plies of tire 

 uck with friction coat on two sides and skim coat on one side applied on 



45-degrec bias. The gage of one ply frictioned on two sides and skita 

 oated un one sh.ill be at least .043-inch. Each ply shall have not more 

 lan two splices which must be at least 7 inches apart measured on the 

 ircumference of the tire. The splices in the tire shall be at least 3 inches 

 part when measured on the circumference of the tire. 



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

 )ng-staple cotton, weighing 17i'4 ounces to the square yard with an allow- 

 ble variance of plus or minus 3 per cent. 



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

 ed through the operations of rubberizing. 



ing practice 



ethod 



ed by til 

 oil of fab 



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. 

 All 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 inches per minute. Six samples shall be cut from each roll in such 

 a manner as to eliminate any unnecessary 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 unravel to 

 23 yards (1-inch widthj, heat until sample is *"bone dry" and immediately 

 test it in machine. 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 rubber core filler as in standard 



of square woven fabric weighing not less than 

 to be used. The chafing strip shall extend upward 

 ,t least }S-inch from the channel of the bead. 



cushion of rubber compound applied over the 

 linimum gage of this 



(g) On 



chafing 

 square 

 of the 



effected. Thii 



the breaker 



e shall be a single bi 

 iidard commercial pra 

 ing the physical and 

 lion between the cus 

 :er strip shall have 



r strip of open-weave 

 coated on both sides 



nical properties of a 

 and tread when the 



nimum width of 2^i 



ighing 





ule of the 





"¥h^ 



I minimum thickness 



(a) Cross sectional ( 

 nded weight and loai 

 nor more than 3.6 in 

 vater pressure of 275 

 5 test to be 



ched- 



be less 

 11 be capable of withstandii 

 ler square inch without apparent injury, 

 retion of the inspector. 



(c) Tlie strength of the union between the plies of fabric 

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



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

 breaker and cushion shall average 25 pounds or more per inch 



ng the standard friction test. 



^ ' * ' ■ i^een the cushion and plies shall 



g the standard friction test, 

 'een the sidewall and plies shall 

 ng the standard friction test, 

 er, bidding on orders for govern- 

 set the following testing conditions: 

 ^o tires are to be given consideration by the Government unless 

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

 d properly check up tests on cars to properly test their pneumatic 



The strength of the 

 average 16 pounds or more p 



(f) The strength of the 

 average 12 pounds or more ] 



5. Road Test, (a) Any 

 ment business, must be prepa 



175 pounds 

 at the dis- 



shall average 



ufact 



the 



nd that the 



eUy. 



The cars, speeds, loa 

 tires are properly tested and 

 see that the above conditions 

 (3) A successful bidder i 

 tires to the government statii 

 duplicates in construction ai 

 tested properly and a sufficii 

 Transport Service, at least ! 

 least 4,000 miles. 



6. Lining. The inside o 

 ance with the standard practi 



7. Flaps. Each tire casii 

 of the casing in accordance 



is and road coi 

 the Governmer 



nust supply an 

 g that the tires 

 d material of 

 nt number of 



average of 2,000 tire miles 



litions must be such that the 

 may appoint an inspector to 

 th. 



iffidavit before delivering any 

 to be delivered are practically 

 res which he has previously 

 res satisfactory to the Motor 

 rerage on the rear wheels at 



:ach tire shall be properly lined in a 

 of tire manufacturers, 

 shall have a flap cemented into the 

 idard commercial practice. 



a) Tread— The tread shall be made from 

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

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

 not exceed 8 per cent weight of new rubber used. Compound shall be free 

 from ingredients known to the rubber trade as '*oil substitutes." The 

 minimum tensile strength of the tread rubber shall be 2,600 pounds per 

 square inch and shall have an elongation of not less than 450 per cent (2 

 inches to 11 inches). The set shall have a maximum of 25 (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 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 charac- 

 teristics 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 extent of 15 per cent of the total compound is allowable, but the 

 amount and kind must be declared by the manufacturer. The minimum 



ensile 



ength of 



sidewall rubber shall be 1.500 pounds per sciuare 

 men witn a minimum elongation of 450 (2 to 11 inches) and a max- 

 imum set of 25 per cent as done in tread test. Compound shall be free 

 from 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 causing 

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

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

 ized 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 or test or analysis necessary to insure the product 

 meeting all requiiremeiits of this specification. 



10. Packing. A1! res shall be spirally wrapped according to standard 

 practice and proper. • abeled on the outside showing size, type and name 

 of manufacturer, anu marked with either tag or label in colors of red, 

 white or blue which will denote as follows; red, first four months of cal- 

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

 months of calendar year; years to be designated by square, triau'gle and 

 round labels or tags, tags or labels to be approximately 2 inches in diam- 

 eter. Tires shipped for original equipment of cars shall be packed as 

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



sha 



lied. 



SPECIFICATIONS FOR PNEUMATIC AUTOMOBILE TIRE 

 CASINGS, SIZE 30 BY 3'i. 



Specification No. 1066. 

 fabric construction. 



1. Genekal. (a) Pneumatic automobile casings m 

 ordance with thi's specification shall be of fabric con«l 

 mown to the trade as 30 by 3yi. 

 " " "" ■ ■ x satisfactory service under a 



ds per square inch, 

 from all defects and fully gua 



load of 570 poundi 



when inflated to 55 poun 



(c) Tires to be free 

 rial and workmanship. 



(d) Tires shall be of the standard commercial non-skid design of the 

 manufacturer furnishing the same. In the case of a manufacturer using 

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

 the option of the Motor Transport Service. A small section of the tire 

 shall be submitted foi apiiroval before contract is let.^ 



(e) The tires shall be plainly marked with manufacturer's name serial 

 number and the size, and marked with either tag or label in colors of red, 

 white or blue, which shall denote as follows: red, first four months of the 

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

 four 'months of the calendar year; years to be designated by square, tri- 

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



(f) As soon as p 

 equivalent millimeter sizes as recomn: 

 Engineers. 



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

 shall be of the clincher type, designed for the standard S. A. E. clincher 

 rim of the size 30 by 3 ^^. 



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

 stripped. 



(b) Carcass of tire shall consist of not less than four or more than five 

 separate plies of tire duck, with friction coat on two sides and skim coat on 

 '»5-degree bias. The gage of one ply frictioned on 

 Each ply 

 ches apart 



be 



shall 

 have not more than two splices which 

 ared on the circumference of the tire, 

 least 3 inches apart when measured on the circumferenc of 

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



least .045-1 

 lust be at least 

 The splices in 



shall 



Egypti! 



vith 



factui 

 i'zing. 



(e) The usual methods of inspection used by tire 

 mercial practice to discover defects in each roll of fabr: 



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

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

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

 proximately 3 inches and the separation of the jaws shall be at the rate of 20 

 inches per minute. Six samples shall be cut from each roll in such a man- 

 ner as to eliminate any unnecessary waste of material. Three samples 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. The 

 results must show a tensile strength of not less than 190 pounds per inch 

 width for either warp or filler. 



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

 commercial practice. 



(g) One chafing strip of square woven fabric weighing not less than 8 

 ounces per square yard shall be used. The chafing strip shall extend on 

 each side of the tire at least 5^-inch from the channel of the bead. 



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

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

 cushion shall be .045-inch, 



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

 weave _ fabric such as i's 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 perfect union between the cushion and tread 

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

 of 214 inches. 



Breaker shall be made from long staple cotton weighing not less than 8 

 ounces per square yard. 



(j) The tread of the tire shall not be 1 

 Va-inch of which shall be the minim.um tl 

 under the middle of the non-skid portion. 



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

 inch. 



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

 of each tire inflated according to the recommended weight and load of the 

 S. A. E. shall not be less than 3-7/16 inches (full size 30 by 3'A pre- 

 ferred). 



lAII sections for approval must 

 Engineering Division, Motor Trans 

 ion. District of Columbia. 



