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.
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.