THE DELTA SYSTEM
As much as we would like to think that everyone will have the opportunity to test ride an Evil, the reality is most of you will buy based on reviews, friends, or Weagle's past successes.
So the following is straight from the horses mouth (Dave Weagle being the horse). The DELTA system was conceived to, among other things, achieve very complex leverage rate curves that can be used to tune for varying track conditions, spring, and damper parameters. The dual progressive leverage rate curve was developed for coil sprung downhill applications to take advantage of the speed sensitive shocks on the market. Mechanically, the system uses very compact links that can achieve a lot of angle and velocity change through the travel. We can tailor the leverage rate curve to really take advantage of the shock's valving and the way that a speed sensitive damper is designed to work. Ultimately the design achieves a high degree of suppleness early in the travel, with a very predictable high traction stage through the middle and a bottomless ramp at the end of the travel.
The whole suspension system, every attribute, is developed concurrently with each other, with the shock absorber, and with the bike's intended use and geometry in mind. Main pivot location was carefully chosen to give the best balance of acceleration and braking performance. This careful positioning lets the bike accelerate without the need for excess damping, which in turn helps us push the limits of shock setup as far as possible to achieve ideal damper setup for any World Cup track. One of the biggest advantages of the system is its ability to let riders and mechanics adjust frame geometry without changing leverage rate and wheel rate at all.