THE INDIA RUBBER WORLD 



421 



coated on one shall be at least 0.043 inch. Each ply shall have 

 not inore than two splices which must be at least seven inches 

 apart, and the splices in the casing shall be at least three inches 

 apart ; all measurements on the circumference of the casing. 



(r) Beads shall be constructed with a core filler as in stand- 

 ard commercial practice. 



((/) Size 29 by 3^ inches shall have one chafing strip of 

 square-woven fabric weighing not less than 8 ounces per square 

 yard on each side of the casing and shall extend upward on the 

 side of the casing at least fs inch from the channel of the bead. 



(c) 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 0.0325 inch for size 28 

 by 3 inches ; and 0.045 inch for size 29 by i'/z inches. 



(f) Over the cushion there shall be at least one breaker strip 

 of open-weave fabric made from long staple cotton weighing 

 not less than 8 ounces per square yard, as used in standard 

 commercial practice, coated on both sides with a rubber com- 

 pound which shall insure a perfect union between the cushion 

 and tread, after cure. 



Breaker Strip for size 28 by 3 inches, minimum width. 1% 

 inches. 



Breaker Strip for size 29 by 3'/, inches, minimum width 2'4 

 inches. 



(g) Rubber DiMEN-sioNS : 



Size inches 28 by 3 29 by 3 M 



Inches, Minimum. 



Thickness: 



Tread of casing in center -A A 



Tread, exclusive of non-skid portion in center '/g <A. 



.Side wall 0.045 0.050 



(/i) Flap shall be cemented inside of casing. 



MARKING, WRAPPING AND PACKING. 



See General Specifications. 



MATERIAL. 



See General Specifications. 



(a) Fabric must be square woven 23 by 23 from Egyptian 

 long-staple cotton, or its physical equivalent as approved by the 

 Government, weighing 17}4 ounces to the square yard. 



(ft) Rubber Compound: 



New Reclaimed 



rubber, per rubber, per 



cent volume, cent weight. 



Minimum. Minimum. 



Tread 65 



Side wall 65 15 



rriction 75 



TESTS. 

 See General Specifications. 



(a) Cross sectional diameter of each tire inflated according 

 to the recommended weight and load schedule of the S. A. E. 

 .■iliall be for 28 by 3 inches, minimum 2-15/16 inches, maximum 

 3-3/10 inches, and for 29 by 354 inches, minimum 3-7/16 inches. 



(b) Shall withstand water pressure without injury, as fol- 

 lows : 



Minimum 



.'S by 3 inches 250 pounds 



-") by 3 '/; inches 275 pounds 



(c) Fabric: Tensile strength, warp or filling, minimum, 165 

 pounds. 



{d) Friction : 



Strength of union between plies of fabric minimum 16 



Strength of union between breaker and tread minimum 28 



Strength of union between breaker and cushion minimum 28 



Strength of union between cushion and carcass minimum 16 



Strength of union between side wall and carcass minimum 10 



(?) Rubber compound: 



Tread. Side wall. 



Tensile strength, minimum 2,200 1.500 



Ultimate elongation, minimum.. iiic/ici 2-11 2-11 

 Set: 



Stretch, minimum 2-10 2-10 



Set 



.fer 



if) Road Tests: 



Manufacturer shall maintain at least one motorcycle used ex- 

 clusively for test work which shall average at least 1,000 ma- 

 chine miles per machine per week, and a sufficient number of 

 casings (not less than six) shall have averaged on the rear 

 ■wheels at least 4,(XX) miles. 



INSPECTION. 



See General Specificat 



AUTOMOBILE TIRE ACCESSORIES. 



See General Specifications for Tires', which arc part hereof. 

 GS 1070— Blow-out Patchei. 



They are recommended only for emergency repairs. A vul- 

 canized repair should be made as soon as possible. 



Patches shall be made at least six-ply 7-ounce fabric, or its 

 equivalent, as approved by the Government. Plies must be 

 properly stepped down, according to good commercial practice. 

 Two ears are required on all patches. The length of the patch 

 must be according to the manufacturer's standard commercial 

 practice. The 3-inch and iYi-'mch must be designed for use 

 with clincher fabric tires and the 4-inch, 4|/l-inch, and 5-inch 

 must be of ample size for use with cord tires. 

 GS 1071— Cementless Patches. 



They shall be of one standard size, V/s inches in diameter. 

 The gage and compound of the stock shall comply with the 

 specification for cured back tube stock as given in the Repair 

 Material Specification. Patches molded to a featheredge are 

 preferred. 



GS 1072- Reliners. 



They are recommended only in case of extreme necessity. All 

 sizes up to 4-inch shall be made of at least three plies, while 4- 

 inch and larger must be made of at least four plies of 7-ounce 

 fabric, or its equivalent, as approved by the Government. The 

 plies shall be built up on the bias, and a lap of at least 6 inches 

 is required and the edges properly stepped off on the sides and 

 skived on the ends to insure against injury to the tube. Each size 

 reliner must be designed so that its width will be such as to 

 properly fit the standard tire of ihat size. This includes 3-inch 

 and iYz-'mch in fabric clincher and 4-inch or larger in cord tires. 

 The edge must stop approximately J4-inch above the toe of the 

 bead. 



GS 1073— Haps. 



Motorcycle flaps must be of the cemented-in type and equal in 

 construction and quality to the flap supplied by the bidder on 

 tires made to Government specifications. 



Straight side-cord tire flaps must be of the floating type and 

 equal in construction and quality to the flap supplied by the 

 bidder on tires made to Government specifications. 

 GS 1074 — Fabric Cord Patches. 



These patches must be made according to the manufacturer's 

 standard practice from carded Egyptian, combed peeler cotton 

 fabric, or their physical equivalent, as approved by Government. 

 weighing not less than 13 ounces nor more than 16 ounces per 

 square yard. 



The plies must be laid on the bias, frictioned or spread and 

 skim-coated on both sides, equally to a minimum gage of 0.043- 

 inch. The compound must fill the specification set forth in the 

 repair material specifications covering friction, skim, cushion, and 

 tube stocks. 



.\\\ sizes up to 6-inch shall be four plies and 6-inch and above 

 shall be six plies. The patch must be properly stepped down 

 and preference will be given to gum-stripped ends to insure 

 against injury to the tube. There shall be applied in the center 

 of the back of the patch a padding not less than 1/16-inch thick. 

 The minimum length and breadth of the padding shall not be 

 less than the length of pad specified below. 



The following sizes are standard and lengths required are given 

 in table : 



Patch, length. Lengtll of pad. 



No. GS 1074X1 3'/5 and ■» inch 10 4 



No. GS 1074X8.— 4 J4 and 5 inch 11 5 



No. GS 1074X8.-6 inch 12 6 



No. GS 1074X4.-7 inch 13 7 



No. GS 1074X6.— 8 inch 14 8 



iThe General .Specifications referred to in these specifications were pub- 

 lished on page 351. in Thf. India Rubber World. March 1. 1920. 



VALVE ACCESSORIES. 

 No. GS 1080X1. 

 Valves : Schrader's 1936 or approved equivalent for motor- 

 cycle tubes. 



No. GS 1060X2. 



Schrader's 725 or approved equivalent for i'/i and 4-incli auto 

 tubes. 



No. GS 1080X3. 



Schrader's 792 or approved equivalent for 4;/. and 5-inch auto 

 tubes. 



No. OS 1080X4, 



Schrader's 2033 or approved equivalent for 6-inch tubes and 

 larger. 



No. GS 1081X1. 



Valve caps : Schrader's 880 or approved equivalent. 



