THE INDIA RUBBER WORLD 



tolal 



mum elongation of 450 per cent (2 to 11 inches) and a maxi- 



f 25 per cent. The compound shall be free from ingredients 



le rubber trade as oil substitutes." 

 sulphur in any of the above compounds shall not exceed S per 

 weight of new rubber used, except as follows: if the mainu'ac- 



:s to _ use sulphur-beariiig mineral fillers, thereby causing the 



do 50, but shall submit for analysis 



«tock. Such stock shall not show a sulphur content i 



■of over 8 per cent of the weight of new rubber used. 



Inspection. The Motor Transport Service reserves the right to 

 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, marked with either tag or label in colors, red, white or 

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

 .vear; 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. 

 Tires shipped for original equipment of cars shall be packed as specified 

 by customer. In the c^se of oversea shipments, the specifications covering 

 ompound shall be free from ingredients known 



make 



this shall be applied. The 



the rubber 



SPECIFICATIONS FOR PNEUMATIC AUTOMOE 

 CASINGS, SIZE 33 BY 4. 

 Specification No. 1068. 

 cord construction. 



Ic) .Ml tires shall be branded with the manufacturer's name, 

 tire, serial number and marked with either tag or label in colors 

 white or blue, which will denote as follows; red, first four m( 

 calendar year: white, second four months of calendar year; blue, 1 

 months of calendar year. Years to be designated by square, triai 

 round labels or tags. Tags or labels to be approximately 2 inches 

 eter. 



(f) As soon as possible, 

 equivalent millimeter sizes a 

 Engineers. 



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

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

 side rim of the size 32 by 3 H inches or 33 by 4 new standard rim. 



3. Construction, (a) Carcass of tire shall consist of no less than 

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

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



(b) 



Ml cord material to be of the best quality combed Sea Island or 



cotton, or its physical equivalent, 



vll cord fabric must be thoroughly dried according to standard 



turing practice before it is started through the operations of rub- 



lactK 



jal methods of inspectio 



det 



defects in each roll of cord fabric sh 



ne the tensile strength of cords shall be 



taken from each roll, these tests shall be 



all be 



;ifficien 



on ten individual cords 

 in the following manner; 



The individual cords shall be tested in a fabric testing machine in which 

 the distance between grips is approximately 10 inches, which grips separate 

 at the rate of 20 inches per minute. The results shown must be up to the 

 standard specification of the individual manufacturer. 



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

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

 as used by the individual tire manufact 

 will be satisfactorj' in so far as they ari 

 of a head stretching or blowing off the rim when under pressure. 



(f) Two chafing strips of fabric weighing not less than 8 ounces per 

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

 side of the tire at least 1 inch from the heel of the bead. One chafing 

 .strip shall extend at least 3/16-inch above the other. 



(i;l 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 .050-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 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 3 inches. 



Breaker shall be made from the best quality of Sea Island or Egvptian 

 cotton, or its physical equivalent, and shall weigh not less than 10 ounces 

 per square vard. 



(i) The 'tread of the tire shall not be 1< 

 center, V^-inch of which shall be the minimum 

 tre,id under the middle of the non-skid portii 



(j) The sidewall of the tire shall have a 



4. Physical Measure.ments and Tests. 

 of each tire inflated according to th 

 ule of the S. A. E. shall be 4.1 inc 



(b) Tire shall be capable of will 

 per square inch without apparent in 

 cretion of the inspector. 



(c> The minimum strength of 

 "strength factor" is the product of 

 at the tread at right angles to the coi 



n the 

 of the 



thickness of .0625- 



shall be 2,000 pounds. This 

 ber of cords per inch measured 

 s strength of individual cord as 



times the number of plii 

 le union between breaker 

 average 32 pounds or m 



inch, using the 

 shall average 14 

 shall average 16 



taken from the cord til 



(d) The strength of 

 breaker and cushion sh 

 standard friction test. 



(e) Strength of the 

 pounds or more per inc 



(f) Strength of the union between cushion and plies 

 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) Wo tires are to be given consideration by the Government unless 

 the company submitting the bid tenders an aflidavit stating that they raain- 

 If„"H ^"/ ''"?''.t,^ J' ."u""^ "P '?^'■^ °" "" '° properly test their pneumatic 

 ■^^o^ "V?""^ "'^' ""^^^ "" ''^'"■" "" average of 8,000 tire miles weekly. 



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

 ivernrnent may appoint an inspector to 

 mplied with, 

 pply an affidavit before delivering any 



' be delivered are practically 

 which he has previously 

 latisfactory to the Motor 

 ged on the rear wheels 



operly tested and 

 see that the above conditions 

 (3) A successful bidder r 

 tires to the Government, stati: 

 duplicates in construction ar 

 tested properly, and a suflicient nurabe: 



least 



have 



Transport Ser 



at least 5,000 miles. 



6. Lining. The inside of each 

 ance with the standard practice of t 



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

 as in standard commercial practice. 



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

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



• i,t "est new rubber, content of sulphur shall not exceed 8 per cent by 

 weight of the new rubber used. Compound shall contain no reclaimed rub- 

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

 square inch and shall have a mm mum set of 25 per cent Set ^ps^ stinll 

 be made by stretching 2 to 10 incnes and hol5in|%or W minutes ' Res 

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

 the original length. giuun 



(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 sliTll 

 "°L''^ T^f i*''^" l,P" ""' ''y "'«'8'>t of new rubber used. No reclaimed 

 rubber shall be used. rcciaimea 



, (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 of weight of new rubber used. No reclaimed rub- 

 , o''on"" ^% "*'"'• Compound shall have a minimum tensile strength of 

 1.800 pounds per square inch and a minimum elongation of 450 per cent 

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



,1-^^ JSi. >"8"dients 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 man- 

 ufacturer desires to use sulphur bearing mineral fillers, thereby causing 

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

 may do so. but shall submit for analysis a sample of the finished unvul- 

 canized 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 labelled 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 bv square, triangle and 

 round hibels or tags— fags or labels to be approximately 2 inches in diam- 

 shipped for original equipment of cars shall be packed as 

 customer. In the case of oversea shipments, the specifications 

 ^u.,.,...B ....s shall be applied. 



SPECIFICATIONS FOR PNEUMATIC AUTOMOBILE TIRE 

 CASINGS. SIZE 35 BY 5. 



Specificatiox No. 1069. 

 cord construction. 



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

 accordance to this specification shall be of cord construction, of the size 

 known to the trade as 35 by 5 inches. 



(b) The tire must give satisfactorv service under a load of 1.300 

 pounds when inflated to 75 pounds per square inch. 

 ee 

 ;d workmanship. 



(d) Tires shall be of the standard 

 manufacturer furnishing the same, or • 

 the order. In the case of a manufacti 

 tread design, selection of the design to 

 Motor Transport Service. A small sec 

 for approval before contract is let.^ 



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

 number and size of tire 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. 



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

 equivalent miUimeter sizes as recommended by the Society of Automotive 



2. Type. AH tires manufactured in accordance with this specification 

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

 straight side rim of the size 34 by 4'A inches. 



3. Construction, (a) Carcass of tire shall consist of no less than 

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

 that an equal number 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 



ghly dried acco 

 •rl tlirough the 



specified by 



mercial non-skid design of the 

 b tread design as specified on 



using more than one non-skid 

 idopted is at the option of the 



of the tire shall he submitted 



