4 6 



WHEEL 



CH. Ill 



especially on a hard road, inasmuch as the grinding 

 action is less (see page 42). On a soft road, the 

 narrow tire will cut in and cause friction, or adhe- 

 sion between the faces of the rim and the mud. 

 The coach w r heel shown in Fig. 26, may be taken 



as a good example, not being 

 exaggerated in any way, having 

 a dish of ^ of an inch. 



There are reasons outside of 

 the purely mechanical questions 

 of draught and strength, which 

 induce builders to dish their 

 wheels and to give them the 

 resulting outward Hare. In a 

 brougham, made to a narrow 

 track, the flare of the wheels 

 gives more room for the bod)', 

 and in all carriages the flare of 

 the wheels throws the mud away 

 from the body. A carriage with 

 nearly vertical wheels will have 

 its panels covered with mud in 

 wet weather. These are good 

 reasons for the practice in certain cases, but as a 

 question of draught, the horizontal, parallel axles, 

 with straight and vertical wheels, are the best ; and on 

 four-horse coaches, the track of which is always wide, 

 a close approach to these conditions is desirable. 



In light vehicles the points of the axles are not 

 only turned down, but they are also turned a little 



Fig. 



