What is the Missing Link?
The missing link connects the chainstay, (which pivots on this link), to the top eye of the spring/damper, thus linking the functions of spring/damper performance to the demand placed on it by the horizontal on the on the chainstay, such as pedaling/chain forces as well as bump and braking forces, in addition to the normal vertical bump inputs from the wheel, through the seatstay and rocker.
What is the greatest advantage?
The advantages are many, but the greatest is the ability for the suspension to stiffen and the geometry to steepen on demand for climbing. The increased effort needed by the rider to climb causes the link to rotate in the opposite direction of shock compression, thus increasing stiffness when needed..
No other suspension design can do this. Almost all current popular suspension systems on the market today use amount of anti-squat, in order to prevent a mushy pedaling response. But too much anti-squat can cause unwanted bobbing in the form of the suspension extending and then releasing at each downward stroke of the crank. And they all use a shock pedaling platform lockout for use on serious climbs.
In any serious climb, the link’s rotational force is enough to extend the shock, raising the rear and causing the head and seat tube angles to steepen by up to 3 degrees. Thus the static angles (and DH friendly) of 66 degree HT and 73 degree ST become a climb friendly 69 and 76 degrees.
Frequently Asked Questions:
Q: You claim that the Missing Link TM offers advantages that are not available with any other design. How can that be true with so many great suspension designs on other bike brands?
A: It is true that there are many great bikes out there with very capable suspensions. The most common and generally highly regarded, are the so-called “virtual” or “floating” pivot. These use a rear triangle that pivots on 2 arms or links. These 2 links provide a pivot in space that creates an anti-squat geometry. This anti-squat provides resistance to suspension compression due to chain and pedaling forces, using the combined forces on the 2 links to essentially “jack” the suspension into anti-squat. Only so much anti-squat can be used or the suspension will extend and release back to sag level with each downward pedal stroke. A high single pivot is essentially an anti-squat suspension, an early Cannondale Super V or Santa Cruz Super 8 were very highly anti-squat and exhibited undesirable extension and release during hard pedal strokes. Even with current state of the art designs, all bikes come with a shock lockout to prevent compression during hard pedaling.
The missing link does not use floating pivot induced anti-squat. Instead, it goes a bit further, by tying in the chain, bump and pedaling forces directly to the top of the rear damper mount, where it is combined with normal vertical bump input from the rocker. In this way, it simply adds or subtracts to the normal spring rate, directly at the shock. More resistance to forward motion, i.e. hill climb, adds a consistent, well modulated amount of spring force. This allows the actual sag level of the bike to be reduced during hard pedaling efforts, by changing the force to directly compress the shock. In a max climb situation, the sag will actually; eventually be at zero, with the shock fully extended. The rider will have been unaware of the extension, as it happens smoothly as climbing effort increase, but the bike will feel like a hardtail, with 3+ degree steeper head tube and seat tube angles than the sag, or static angles. There is no extend and release with pedal strokes. In fact , a lockout is completely redundant and unnecessary.
But when you hit a bump, the link automatically rotates the opposite direction, making the spring rate softer, allowing the shock to easily compress over the bump.