Flow Control Servo Valve with Integrated Electronics & Sensors Creates a Revolutionary Suspension System

Cannondale has a long history of being the most innovative and technically savvy manufacturer of high-performance bicycles. Once ridiculed for making frames with oversized thin-wall aluminum tubing, that design approach is now standard for state-of-the-art bikes. The "Lefty," with only one large tube holding the front wheel on a spindle rather than a traditional two-tube fork, shocked the market with its sheer engineering audacity. Skeptics were silenced when the Lefty proved to be lighter, smoother and more rigid than conventional forks. And now they've shocked the market with a new shock absorber. "Simon" is the first fully autonomous, realtime, electronically controlled mountain bike suspension that monitors ride conditions and reacts to bumps, jumps and vibrations – often damping an impact so quickly and smoothly that the rider never knows it happend.

Enfield Technologies was in the midst of developing the PD-9000 Platform when Cannonale called to find a proportional hydraulic valve unlike anything on the market. The design requirements and challenges were extreme:

• Shift from lock-out to an oil flow rate of 38 liters/min within 8 ms
• Tolerate high temperatures because damping converts mechanical energy into heat – and much of this would occur within the valve
• Operate at high pressures (20+ bar) with occassional spikes as high as 50 bar, and contain these pressures within a very thin walled heatsinking shell
• Fit within the Lefty's existing hollow carbon tube, with a size budget of 40 mm diameter x 120 mm tall and no more than 275 grams
• Serve as a load-bearing interface between the shock absorber and the sterring column, with g-forces as high as 200
• Modulate flow with resolution better than 0.2% and a 5% incremental shift bandwidth greater than 1000 Hz

Cannondale was among the first projects, as a beta-test application, to utilize the PD-9000 outside of Enfield Technologies-branded products. Key elements of the platform were quickly integrated into a modified cartridge housing with customer-specific adaptations for porting and digital communication protocols, plus an adaptation of a spool-style metering element.

In two months, a fully operating beta prototype was mounted to the shock absorber pistion assembly. This allowed other important aspects of the overall bicycle and suspension design to move forward and reduced overall development and time-to-market by at least 2 years. With the PD-9000 Platform as a starting point, the beta design was achieved at a fraction of the likely $175,000+ engineering cost and 9-15 month project for a ground-up design to achieve a less functional initial "alpha" proof-of-concept.

The result is unprecedented dynamic control of suspension damping without intervention by the rider who can enjoy the ride in greater comfort and pay better attention to the trail. Once again, Cannondale has demonstrated its continuing market leadership in innovation while lowering development time, cost and risk. Cannondale's VP of R&D said, "We wanted to program the Simon fork to perform nearly any suspension response desired by the rider... The fork's performance hinges upon the speed and precision of fluid flow... Enfield Technologies was an invaluable development partner in meeting that aim."