THE INDIA RUBBER WORLD 



[August 1, 1916. 



British Standard Solid Tire Rims. 



THE pioneer work in connection with the standardization of 

 solid tire rims in Great Britain was undertaken by a select 

 committee of the Society of Motor Manufacturers and 

 Traders, Limited. From data obtained from the wheel and tire 

 manufacturers it was found that there were 173 wheel diameters 

 in use, all more or less closely approaching one another. The 

 data were analyzed, and by a careful process of elimination it 

 was found possible to reduce the number to 6 standard sizes, 

 and at the same time cover practically all the requirements of 

 the commercial motor industry, and these were finally adopted 

 as British standards by the Engineering Standards Committee, 

 the body which fixes and regulates British mechanical standards. 



The task was a heavy one. It was found, for example, that 

 where the suitable size of tire might be 900 by 120 millimeters 

 [35.43 by 4.72 inches], the correct size of rim, as quoted by five 

 of the principal manufacturers, was 719.8 millimeters [28.32 

 inches], 72'l millimeters [28.39 inches], 740 millimeters [29.13 

 inches] and 742 millimeters [29.21 inches]. 



Further simplicity was afforded by dropping all reference to 

 the outside diameter of the tire; every standard size being desig- 

 nated by the diameter of the rim on which it fits, together with 

 the dimension for the width of the base. 



The official report of the Engineering Standards Committee 

 reads, in part, as follows: 



1.— SIZES OF RIMS. 



British Standard Solid Tire Rims for Automobiles shall be 

 made to the outside diameters given in column 1 of the table, 

 and shall measure at a temperature of 60 degrees F. not less 



than the minimum 

 more than the 



in column 2 and not 

 given in column 3. 



Cir 



Millimeters. 

 2,104.9 

 2,262.0 

 2,327.9 

 2,422.2 

 2,670.3 

 2,767.7 



•Th< 



J0.35 



I 33.46 



34.69 



Committee recommends that for general 



82.83 

 89.06 

 91.65 

 95.35 

 105.12 

 108.94 



2,107.9 

 2,265.0 

 2,330.9 

 2,425.2 

 2,673.3 

 2,770.7 



91.73 

 95.47 

 105.23 

 109.06 



pensed with. 

 2.— MINIMUM 



WIDTH OF 

 STEEL RIMS. 



Where n 

 raised flange 

 used the width ( 

 the rim shall be 

 such as to pro- 

 vide not less than 

 10 m i 1 1 i meters 

 [.3937 inch] 

 overhang on each 

 side of the wheel 

 beyond the tire 

 base (see Fig. 1 ). 



3.— LE.'KD TO 



FACILITATE 

 FITTING 

 OF TIRES. 



A lead of 10 

 mm. [0.3937 inch 

 wide and 3 mm. 

 [0.1181 inch] 

 deep (See Figs. 1 

 and 2) shall be 

 provided on one 



- /n/</r/7e<f /^/srtffe 



Rim of Steel. Wheel in Section. 



edge of the rim to facilitate the fitting of the tires. 



4.— SLOTS TO FACILITATE REMOVAL OF TIRES. 



In case of steel rims having fixed raised flanges the Committee 



recommends that the slots to facilitate the removal of tires (see 



Fig. 3) be spaced at equal intervals, round the rim and be not 



less than 100 millimeters [3.937 inches] in width. For rims up 

 to and including 771 millimeters [30.35 inches] in diameter the 



//of /ess -f-Ztg/j 3.937/h yy/'t/e-^ 



Side Elev.\tio.\ of Fig. 2 Showing Slot. 



slots shall be four in number, and for rims above 771 millimeters 

 [30.31 inches] in diameter the slots shall not be less than four 

 in number and have a combined length of not less than 600 milli- 

 meters [23.62 inches.] 



The Committee recommended that either an inturned flange 

 (A, Figs. 2 and 3), or suitable pads or rests, spaced at equal 

 intervals around the rim, be provided for the support of the 

 steel blocks used 



in removing the Z' /^^ 



tires. 



B.S.? 850 DIA. 



VMPLE OF St.SiXD.^RD MaRKII 



Rim. 



6.— MARKING OF 

 RIMS. 

 The rims of all 

 wheels for solid 

 tires which pur- 

 port to comply 

 with the British 

 standard outside 

 diameters and 

 limits for circuin- 

 ference laid down 

 in Clause 1 of 

 this report, shall ' 

 be marked on the pj„ ^ p 

 external surface 

 of the rim (as 

 shown in Fig. 4) 



with the standard outside diameter (Column 1), and also with 

 the letters B, S and the Committee's brand as prima facie evi- 

 dence adduced by the manufacturer that the rims are in accord- 

 ance with the diameters and limits laid down in Clause 1. The 

 letters shall be not less than 10 millimeters [0.393 inch] high and 

 the arrangement of the marking shall be as shown in Fig. 4. 



7.— MARKING OF SOLID TIRES. 



The Committee recommends that every solid tire be marked on 

 both sides, in such a manner as to indicate clearly the width of 

 the tire base and the diameter of the standard rim it is intend 

 to fit; for in- 

 stance, "120 for 

 850" [4.72 for 

 33.46 inches] 

 would indicate a 



tire 120 millime- V///y////////////\ i nr\ O c/% 



ters [4.72 inches] ^^^^^^^ IlUFORoDO. 

 wide to fit an 850- '//////////-^/////^-^ 

 millimeter [33.46 

 inches] diameter 

 rim. The figures 

 are to be molded Fig. 

 on the tires, im- 

 mediately follow- 

 ing the marker's name, in the position shown in Fig. 5 and to be 

 not less than 10 millimeters [0.393 inch] high. 



A study of the table of standard rim sizes, given in the above 

 report, shows that the limit of accuracy to which the wheels 

 must be turned, and the tires bored, is fairly fine, taking into 

 consideration the class of work. Such accuracy is justified, 

 however, under the circutustances. It should be remembered that 



Example of Standard Marking for 

 Solid Tires. 



