When ultimate suspension efficiency and control on the trail are required, nothing compares to the Specialized Brain. Found on the Epic and Stumpjumper HT XC race machines, and super-versatile Stumpjumper FSR trail bike, the Brain has been refined and tuned to perform on varying terrain for the sport’s most demanding riders. The Epic is the first full-suspension bike to win a Cross-Country World Championship (it’s won several in fact), and in each of those victories riders were propelled to victory aboard the one-of-a-kind Brain shock. Not only the go-to choice for full-suspension endurance racers, the trail-tuned Brain shock has elevated the Stumpjumper FSR above and beyond its legendary status.
WHAT DOES THE BRAIN DO?
Simply put, the Brain allows the rider to go faster with more control. The idea came from understanding that hardtails are great at pedaling, while full-suspension bikes handle better in the rough; the Brain puts those two together. With its inertia valve technology, it knows the difference between rider inputs (pedaling) and terrain bump forces (rocks, ruts, and roots), meaning it is firm on smooth terrain to transfer all of the rider’s pedaling effort into forward motion, and then instantly transitions to active in the bumps to maintain more control.
HOW DOES IT WORK?
The Brain technology is based around an inertia valve design. A weighted mass sits on a light spring, limiting the flow of oil. On smooth terrain, this means oil is not flowing, so the suspension stays firm for efficient pedaling. When the wheel strikes a bump, the weighted mass overcomes the spring, immediately allowing oil to flow and the shock to become active. Once the compression of the bump is complete, the rebound action combined with the spring push the mass back in place, limiting the oil flow again, and instantly putting the shock back to firm. The Brain reservoir is remotely attached to the main air spring because the closer the inertia valve is to the wheel (or impact) the more sensitive the activation of the valve becomes. The same principle applies to Brain forks, and so in all fork designs, the inertia valve must be located in the lower portion of the fork also known as the un-sprung mass of the assembly.
Also, the orientation (or angle) of the inertia valve is critical to the performance. When the wheel strikes a bump, there is an impact load trajectory. The inertia valve is most sensitive when aligned with this trajectory path.
FSR + BRAIN
The FSR linkage system is the best design in the sport at eliminating power induced movement of the rear suspension system. The active and independent system remains neutral and unaffected as power is applied through the system. We use the Brain technology to stabilize the chassis from the rider’s weight transferring inputs (like aggressive pedaling) with the pedal torque induced movements being neutralized by the FSR linkage.
THE BRAIN GETS SMARTER
Since its introduction in 2003, the Specialized Brain shock has been refined to give riders the optimized ride quality they’re looking for. Director of Suspension Technology, Mike “Mick” McAndrews, thought up the original Brain shock and has been hands on every step of the way.
“The original Brain was more of a macro-event type of damping switch. Based on trail conditions, it would go into either a bump mode or a pedaling mode and stay there for a while, resulting in some inefficient transition time. With the newer generation of Brain shocks, the system can detect micro-trail events and adjust accordingly. There has been a lot of effort the past few years on improving the Brain sensitivity and blending the flow circuits to improve the shock’s first strike capability. Also, important to the XC rider, the current Brain shock uses our own micro damper design that is half the weight of the original Brain shock design.
“We tune the Trail Brain shocks with a slightly lighter pedal platform. For XC racing, it’s important to have this platform firmer so the chassis movement is minimized during aggressive out of the saddle pedaling. For the trail rider, we lower this threshold to a point where it is still effective at stabilizing the chassis for in-the-saddle pedaling, but with the lighter threshold, the trail rider can push through the platform when needed giving the Stumpjumper FSR those playful attributes the rider is looking for.”