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Cannondale presents Simon, the electronic one-legged suspension fork


January 5, 2010

Cannondale's prototype Simon computer-controlled suspension fork

Cannondale's prototype Simon computer-controlled suspension fork

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After five years of development, Cannondale Bicycle Corp recently unveiled a new proof-of-concept prototype that could revolutionize bicycle suspension. Called Simon, it’s the newest member of their offbeat Lefty line of one-legged shock forks. According to Cannondale, Simon’s onboard microprocessor will allow users to customize their ride like never before. If that isn’t enough, it can also send the fork from being fully-open to fully-closed in just six milliseconds.

You start by telling Simon a bit about yourself. Utilizing the stem-mounted LCD screen and bar-mounted joystick, you enter your physical specs and riding preferences, then choose between one of five suspension modes: Cross-Country, All-Mountain, Downhill, Travel Management (for hill-climbing) and Lock-Out. Once you hit the trail, an optical sensor keeps track of where the fork is within its 130mm travel distance, and an accelerometer detects hits to the front wheel. Every time a hit is detected, the shock’s energy damping mechanism is instantaneously adjusted according to the suspension mode and rider data.

Damping mechanisms are the heart of any shock absorber, as they are what allow it to soak up the hits, as opposed to bouncing crazily up and down and bottoming out. On most forks, damping is achieved via a piston that forces oil through small orifices. The size and/or number of open orifices determines the amount of damping, and keeps it at that level until reset by the rider. On Simon, there is only one orifice, but its size is readjusted 500 times a second by a retractable pin. The larger the trail bump that the accelerometer registers, the farther out the pin is pulled, and the greater the amount of energy absorbed.

The damping pin is moved by a very speedy linear-force motor, and that motor draws its power from a rechargeable lithium-ion battery. Unfortunately, the battery pack does add to the weight and girth of the fork. The whole system weighs four pounds, which isn’t awful, but is still a pound more than the current top-of-the-line Lefty. Although the battery is said to last for up to eight hours, that estimate goes down to just two hours for exceptionally bumpy trails. Company reps have suggested that riders could pack a spare battery, although that would involve extra weight, expense and hassle.

At this point, there is still no set release date or price for Simon. In the meantime, some of the technology may trickle down to existing Cannondale products, including rear shocks.

Once Simon is available for purchase, it will be interesting to see how the mountain biking community reacts to it. While it promises unprecedented performance, some riders might question whether menus, submenus and electric motors belong in the realm of mud, sweat and gears.

For an earlier example of a computer-controlled suspension fork, check out the late-90’s K2 Smart Shock.

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away. All articles by Ben Coxworth

Instead of a battery, could they use a capacitor? After all, it would be constantly recharged as the bike travelled across bumpy ground. If it is not bumpy, then of course the shock absorber will not need to absorb so many shocks.


very good summary. as a mtn biker, i tend to glaze over when things get super technical (yah i make a great downhiller btw, lol), but this was a good summary of some fascinating tech.

Frank Hwang
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