Cycle Repairing and Adjusting
With a Chapter on building a Bicycle from a Set of Parts

88 CYCLE REPAIRING The after expenditure will be plating fork crown, if thought necessary, enamelling frame and fork blades, and tyres. Working Drawing.—The first thing to do is to decide on the size of frame required, and make a full-size drawing (Fig. 36). The average-size frame is 24 in., measuring from the centre of the bracket to the top of the seat lug ; this suits a rider of 5 ft. 6 in. to 5 ft. 8 in. A shorter or taller rider will require a corresponding shorter or taller frame. Make the drawing full size in chalk on a wall or board. No details are necessary ; but simply a line drawing to assist in cutting tubes and fitting up to the correct angle and lengths. Mark the ground line. 14 in. above this describe a 28-in. circle for the back wheel (that is, if 28-in. wheels are decided on), mark the bracket centre 12 in. from the ground line, and at a distance from the back-hub centre to give the centre decided on. Draw a line from the bracket centre to the hub centre to represent the back forks. Knock together temporarily the seat tube into the bracket and all the front tubes and lugs, as this will be the best guide for filling in the other lines to the correct angle to suit the lugs being used. Draw a line through the centre of the head tube parallel with the down tube, to represent the steering angle. In front of, and parallel to, this draw another line at a distance equal to the amount of curve on the front-fork blades. On this line, 14 in. from the ground line, will be the front-wheel centre. The position of the top tube will, of course, vary with the height of the frame being built ; but should be parallel with the ground line, unless a racing frame with sloping top tube is desired,