chain pull and reaction force at the tire ground interface pushes the wheel 20 and chainstay 26 forward relative to the frame 12 this forces the lower end of link 40 forward and the upper end of link 40 rearward with the upper shock mount 32 along with it when the upper end of link 40 moves rearward it also moves the lower end of driven link 46 to the rear this changes the motion ratio and rising rate characteristics of the shock 30 to become stiffer in the initial part of the travel it also causes a steeper more vertical fork rake and seat tube angle and places the rider in a more aggressive position over the pedals and moves the rider weight bias to the front since the lower end of link 40 moves forward the attached chainstay 26 is at its shortest length relative to the frame for enhanced optimized or maximum climbing ability the harder the pedaling effort the more the chainstay 26 is forced forward pushing the lower end of link 40 forward and the upper end of link 40 rearward at one extreme as shown in fig6 the link 40 can rotate to the degree that the vertical force on the rear wheel 20 acting through the seatstay 24 and the rocker 28 tries to rotate the top of link 40 further rearward further delaying impeding the top of the link 39 s tendency to rotate to the front under braking and or bump forces for example this might be more desirable for a bike that was made specifically for climbing this alignment of pivots 32 42 48 can be geometrically configured to occur when the upper end.