Inside the Walker Evans â€œNeedleâ€ Shocks
The 2007 Polaris Dragon is fitted with a trick set of Walker Evans Racing shocks; remote-reservoir needle shocks with 16-position compression clickers, front and rear.
Notice the bypass hole in the shock shaft. As the shock strokes, oil flows through the end of the shaft and through this single bypass hole, providing a (controlled) position sensitive function. This allows a small amount of oil to bypass the shim stack during normal stroking. A tuning needle is fixed at the end of the shock body, so when the shaft travels and meets the needle the oil flow through the bypass hole is first reduced, and then effectively shut off approaching full stroke. The needle length and taper can be used as a tuning device to vary the â€œtransitionâ€ point, much like the height and taper of a jet needle in a carburetor. You can see the familiar piston and shim stack as well, with rebound and compression sides. There is no rubber jounce stopper; the shock travel is limited hydraulically and allowed full stroke capability for maximum suspension travel.
Don’t let the â€œposition sensitiveâ€ function fool you; these are very capable shocks with a wide range of calibration capability, from cross country duty to being compliant on the trail. They’re not â€œsoftâ€ like the original PPS shocks from the EDGE models. This is a lighter and simpler way of integrating the benefits of bypass valving without compromises.