44 WHEEL CH. Ill 



important reason for at least a small amount of 

 dish. 



In turning a corner, the centrifugal force acts in 

 the same way upon the outside wheel. 



In some heavy vehicles we find wheels made with 

 a slight dish, but fitted on horizontal axle-arms, so 

 that the face of the wheel is vertical, but the bottom 

 spoke not plumb ; this dish gives strength to the 

 wheel and is not a disadvantage, since the bottom 

 spoke approaches the vertical when the vehicle in- 

 clines sidewise on the down side of the road. On 

 the continent of Europe, this construction is very 

 common in carts, which frequently have wheels 6 

 feet high. 



It must be noted that in a small, heavy wheel 

 the width of the spokes compared with the 

 y-r diameter of the wheel is so great that any 

 line representing a moderate dish falls en- 

 tirely within the substance of the spokes, as 

 shown by the dotted lines in Fig. 25 ; such 

 a wheel is therefore strong-, although not 

 really dished. 



' Nimrod,' in The Road (1832), prefers 

 straight, vertical wheels, and speaks of the 

 mail-coach wheels as being the best ; made with a 

 large nave, every other spoke framed perpendicular 

 to the nave ; the others behind the line. 



Since these old wheels were made with 'strokes,' 

 and not with hooped tires, a part of the advantage 

 of dishing the wheel was lost. Strokes were tires 



Fig. 25 



