THE INDIA RUBBER WORLD 



549 



MOISTURE CONTENT OF AUTOMOBILE TIRE 



FABRIC AND ITS INFLUENCE UPON THE 



WEIGHT AND TENSILE STRENGTH. 



By ll'aiti-r S. Lczcis and C. J. CU-arx.* 



IT is well known that cotton fiber is hygroscopic. The extent 

 to which it will absorb or give up its moisture content 

 depends upon the condition of the material and the relative 

 liumidity and temperature of the air by which it is surrounded. 

 Under changing atmosplieric conditions, tire fabric may some- 

 times vary in moisture content from 3.5 to 8.5 per cent. 



.-Automobile tire fabric is usually sold in rolls of from 100 to 

 500 yards each. . In some instances moisture is intentionally 

 added to the cloth when it is rolled for shipment. This mois- 

 ture is sometimes added to increase the weight and strength of 

 the fabric and sofrietimes to improve its appearance. Cotton 

 tire fabric under such conditions may contain from 3.5 to 10.5 

 per cent of moisture per 100. parts of dry material. 



The quantity of uncombined water present jn the fiber has a 

 marked influence upon the weight and strength of the fabric; 

 to a less degree, the width and elongation and the crimp of 

 the yarn. 



From preliminary tests upon combed Sea Island tire fabric 

 the results have shown that for each 1 per cent of moisture 

 content, upon the basis oi'-lOO parts dry material, there is an 

 increase in tensile strength of approximately 7 per cent. This 

 ratio of strength to moisture content was based upon results 

 obtained from tests upon fabrics which contained from to 10 

 per cent of moisture. 



If dry fabric, therefore, has a tensile strength of 200 pounds 

 per inch of width, it woujd test 249 pounds with 3.5 per cent 

 moisture, 319 pounds with 8.5 per cent, and more than 325 

 pounds with 10.5 per .cent moisture content. There is thus a 

 difference of 70 pounds in tensile strength of the same fabric 

 caused by a 5 per cent difference in its moisture content, i. i'., 

 between 3.5 per cent and 8.5 per cent. 



A consideration of the variation in weight of fabric is also 

 important, especially when it is bought upon the pound basis. 

 What is known as a 17;4-ounce tire fabric, under so-called nor- 

 mal atmospheric conditions, will weigh approximately 16>^ 

 ounces under bone-dry conditions. Therefore, with 3.5 per 

 cent moisture it would weigh 17.08 ounces and with 8.5 per 

 cent moisture 17.90 ounces per square yard, a difference of 

 about 5 per cent in weight. On a roll of 500 yards a difference 

 of 5 per cent in weight would mean 25 pounds. 



Many tests for the determination of moisture have been made 

 during the past year upon 17'/4-ounce tire fabric. The particular 

 fabrics employed in this preliminary investigation were pro- 

 duced and tested by four prominent cotton mills, three located 

 in the North and one in the South, and all tests were made 

 upon cloth which did not have mofsture added artificially when 

 being wound into a roll. In otlier words, the rolls Were shipped 

 in box cars to the purchaser as wound under ffle normal con- 

 ditions of the mill. The rolls were sometimes exposed for a 

 few days only, while in other instances they were exposed for 

 weeks to the different air conditioiis that obtain in the winter 

 months in unheated cars and during the summer months in 

 ordinary box cars. *' 



The tests included altogether more than 200 rolls and mnn 

 than 400 samples were tested. The results were as follows : 



Miiixo. 1 : ..::..;^'. "^"^r 



■t 4.6 



.•\vcragc 4.85 



The extreme variation of moisture was between 3.5 and 6.5 

 per cent, no single sample reaching as high as 7 per cent. 



•From Technologic Paper Xo. 68 of the Unrcaii of Standards. . 



EMPIRE RED TIRES AND TtJBES. 



.\ bright red color is the distinguishing feature of Empire 

 tires and tubes that are said to deliver the maximum mileage 

 with a minimum cost per mile. The casing and tread of the 

 non-skid tire are made of a durable red rub- 

 ber compound which, combined with depend- 

 able fabric base, has shown, according to the 

 manufacturer, superior strength and wearing 



Bf'Tl / ^^J qualities on the road. The red tubes are 



IJJ / E| : thick, tough and elastic and can be repeaterdly 



I ir* Vf, repaired. 



The best quality of rubber and eft'ective cur- 

 ing are the basic factors that are carefully 

 considered by the makers of Empire tires arid 

 tubes. .\11 sizes and types of oversizes are 

 fiirnisbcd; only in red, however, including 

 ClmciuV. ,Q. b. Clincher and Straight Edge 

 tires uith ttibes to correspond. [Empire Rub- 

 ber & Tire Co., Jrenton, New Jersey.] 



THE KOKOMO "KOED" BICYCLE TIKE. 



A bicycle tire that, according to its manufacturers, is im- 

 mune from the effects of stone bruises and is much harder to 

 puncture than the ordinary kind, is of special interest to bicycle 

 riders and dealers. As the 

 illustration shows, it is 

 made up with an inner air 

 tube of heavy black rubber; 

 a layer of strong, specially 

 treated cords, laid diagon- 

 ally ; a layer of black rub- 

 ber, another layer of cords 

 laid transversely to the first, 

 and over all the outer 

 covering of best quality black rubber and a non-skid tread 

 ribbed longitudinally. It is claimed that the "Kord" tire loses 

 nothing in resiliency and is easy to repair. [The Kqkomo Rub- 

 ber Co., Kokomo, Indiana.] - .- 



^^^y^^4^^ 



THE LANCASTER WIRE GRIP TIRE. 



"A wire grip tire with a thousand claws" is the pointed state- 

 ment that is intended to attract public attention to the non- 

 skid puncture resisting qualities of the" Lancaster tire. 



The non-skid 

 and the resist- 

 ance - to - punc- 

 ture effects are 

 obtained by 

 f'Uir spiral coils 

 i)f steel wire 

 ^^ ^^^^^ that completely 



^^^tt .J^^^^^ encircle the 



^^^ ^^^^^ After the tire 



has been' used 

 for a few miles, 

 the wires wear 

 through, form- 

 ing thousands 

 of steel points 

 that grip tlie 

 road. M o r e - 

 "^■- ■■ ' over, the closely 



res shield tlic tread, thus protecting it against 

 Reinforced by the wire coils and strengthened 



intermcshed w 

 glass and tin. 



