Inside Fox's 36 180 FIT RC2 Cartridge - Eurobike 2010

Fox had this very cool cutaway on display showing the insides of the FIT RC2 cartridge that is used in some of their 36 180 mm and 160 mm forks. For 2011 the new cartridge is inverted from the previous year, with the compression assembly and bladder now residing at the top of the leg and the rebound being found at the bottom. While this photo makes the internals look quite complicated - which of course they are - once you get a handle on the technology it will become much more clear. If you look closely at the photo above you should be able to spot the rubber bladder which sits just inside of the stanchion tube walls. The bladder serves to compensate for the oil displaced by the damping rod entering the cartridge. Because there is close to zero air within the oil filled cartridge, there needs to be space for the extra volume to go to as the rod enters the cart, which the rubber bladder accomplishes by expanding. The large gold colored spring at the center of the fork is the high speed compression spring. Turning the H/S dial atop the fork leg preloads this spring which holds down the shims that control the high speed oil flow. The more preload on the shims, the higher the oil force needed to flex them and the more high speed compression damping you'll have. Moving further down into the fork you may notice a second smaller diameter spring that is holding a single large diameter shim in place. This acts as the compression check valve, letting oil flow freely during the rebound stroke, but forcing the same oil through the compression assembly when the fork is being compressed. Not shown in this photo is the fork's hydraulic bottom out which is found on the coil sprung models, but absent on the air versions due to the air spring's inherent rising rate as the fork is compressed and volume decreases.

Compare this labeled photo to the cutaway shot above in order to better understand each part that makes up the FIT RC2 cartridge. While it's easier to just jump on your bike and shred, some basic knowledge of just what is happening inside your suspension as you ride is good to know and can aid in proper setup. Get your geek on and watch the video, study the words and photos, and impress your friends.

Kashima goodness as found on Fox's 36 lineup of forks. By adding Kashima coating to the stanchion tubes of select models, Fox aims to both increase suspension activity by limiting friction between the upper tubes and the seals and bushings, as well as increasing the working life of the stanchions themselves. Oh ya, it looks great as well.