11. The two wheels share a common coil spring running horizontally between the tops of the crank arms . 12. Chainrings designed for use with multi-chainring crank arms may have ramps or pins to aid in shifting. 13. The rider's feet are perfectly flat on the pedals with the crank arms perpendicular with the ground. 14. All your weight is pushing down on that crank arm and twisting that axle and trying to break. 15. This ground level is the axis on which both the crank arm pivot-point and the slider pin are positioned. 16. The two wheels per bogie, two crank arms , springs between the cranks and single mounting point are all evident. 17. Next, from the free point on the crank arm , draw the follower link using its measured or given length. 18. Q Factor is a function of both the bottom bracket width ( axle length ) and the crank arms . 19. This position should put the new crank arm at an angle of 180 degrees away from the retracted crank arm . 20. However, because the stroke of the mechanism only depends on the crank arm length, the follower length is somewhat insignificant.
