Fox Announces New FIT4 Fork Damper & Roller Bearing Kit for Shocks

A good portion of Fox's success in the high end fork market can be contributed to its FIT damper. Lighter riders and those of us who like supple suspension tunes, however, have complained that Fox's FIT4 dampers are too heavily damped in the initial stroke. Fox has addressed this with a running change that includes a smaller diameter, eight-millimeter shaft, a lighter shim stack, modifications to the rebound circuit and a reconfigured FIT bladder. Reportedly, the new damper assembly also saves 35 grams and Fox assures us that their new tune retains the mid-stroke support that we have come to depend upon.

Fox plans to upgrade all of its non step-cast forks (36, 34 and 32 FIT4 forks) with the new cartridge as a running change and will also offer it, along with the roller bearing shock eyelet kit, as aftermarket options. It's a positive step for Fox and an opportunity for existing FIT4 fork owners to stay current without having to pony up for new ones.

The aftermarket roller bearing kit came on the heels of that announcement and should make a lot of riders happy. Technically, roller bearings are the best option for highly loaded, slowly rotating applications - and they take up very little real estate compared with ball bearings. Sealing slender-profile roller bearings from the elements, however, has been problematic. Fox seemed to have solved the sealing issue with eyelet inserts that look like tiny headset cups. The larger-diameter cups can accept better seals and bearing components. 

FIT4 Damper Upgrade & Roller-Bearing Shock Hardware Kit

Fox has implemented an important update to model year 2020 forks equipped with the FIT4 damper, and also introduces a new, low-friction roller bearing rear shock mounting hardware kit.

2020 FIT4 Damper Update 

On the compression side, all 2020 FIT4-equipped forks now feature an 8mm damper shaft, new bladder construction, and a reconfigured shim stack. The 8mm damper shaft has a smaller cross-sectional area, therefore it pushes less oil through the base valve, allowing for less damping. The updated FIT4 damper provides more sensitivity while also maintaining low-speed compression support during aggressive riding, giving riders the ability to tune their fork to feel playful, aggressive—or both.

The rebound side implements Fox's latest tuning improvements through a wider opening check valve and a reconfigured shim stack. The new FIT4 damper assembly construction is lighter as well, with an average weight savings of 35 grams.

This update is implemented on all 2020 FOX 32, 34, and 36 non-Step Cast fork models featuring FIT4 dampers. Step Cast fork models received this damper makeover in MY19.

In its fourth generation, the patented FIT4 closed cartridge system provides three on-the-fly compression damping positions—Open, Medium, and Firm—to adapt to varying trail conditions. Factory Series forks feature 22 clicks of low-speed compression adjust in the Open mode, allowing riders to fine-tune their exact damping preferences. FIT4 is the damper of choice for riders looking for a lightweight fork with lockout and loads of performance.

Roller Bearing Shock Hardware Kit 

Also new for 2020 is an 8mm x 30mm roller bearing shock mounting kit (part# 812-06-096-KIT). Deploying outboard-mounted full complement roller bearings—as opposed to standard bushings—allowing the shock to move more freely as the frame cycles through its travel. Roller bearings reduce friction and improve performance to such a degree that, in some cases, more rebound damping and/or low-speed compression damping may be needed in order to compensate for the decrease in friction.

The roller bearing shock mounting kit is compatible all current Fox shock models and it is also compatible with many popular brands such as Santa Cruz, Transition, and many others. A special tool is needed to remove the bearing kit from the shock—Mounting Hardware Bearing Assy Install and Removal (part# 803-01-406).