$1,599.99 USD

FOX Factory AM, Lynx, Boondocker DS 3900/4100, FLOAT 3 QSL-QSR LW

Part Number: 853-21-016


FOX Factory AM, Lynx, Boondocker DS 3900/4100, FLOAT 3 QSL-QSR LW

The new FOX FLOAT 3 EVOL Quick Switch (QS) are the lightest mountain sled suspension package available. Ride harder in the backcountry with less fatigue without a compromise of durability. Experience a new sense of control on the snow due to less outboard weight. 

Fox designed the air-sprung mountain shocks with two primary objectives: weight reduction and ride performance. FOX optimizes the FLOAT 3 EVOL QS shocks through material reduction without a sacrifice of ride quality or structural integrity. We shaved weight from the reservoir walls and mounting hardware to save weight where it counts. The result is an air shock package in a league of its own.   

FOX’s position-sensitive damping technology, with origins in desert truck racing, is now applied to the Factory Race Series shocks. Spiral grooves inside the shock allow the oil to flow around the main piston reducing damping force in the ride zone for a plush feel. The bypass grooves terminate through the final 30% of the travel, forcing oil to only flow through the main piston and providing a significant increase of bottom-out resistance to cushion any hard hits. Our goal was to inspire confidence next time you send it big thanks to the extra support.  

FOX’s QS technology allows you to adjust the compression and rebound damping with ease to suit the snow conditions. Three positions keep the adjustment simple, so you focus on the ride instead of counting clicks. The FLOAT air spring and EVOL air chamber have an infinite range of spring adjustment. The air spring allows you to tailor the suspension specifically to your ride style or terrain. When the shock compresses through the travel, the spring force ramps up due to the progressive nature of air springs. If you ride aggressively and want a bottomless feel, the FLOAT 3 EVOL QS shock package is for you. 

Maximize the powertoweight ratio of your sled by bolting on FOX’s new mountain shocks.

Additional information



O.E. P/N / Kit Number


Shock Tech Info

Adjustments FLOAT air spring
EVOL air chamber
QS3 – 3 position compression (front track), with lockout mode (rear track)
QSR – 3 position rebound
Features Optimized lightweight shock design
Spiral groove bypass
One-piece, aluminum spherical bearings
High-flow velocity-sensitive damping
Fully re-buildable and re-valvable
Front Track Extended Length 13.880
Front Track Compressed Length 10.240
Front Track Travel 3.640
Rear Track Extended Length 21.680
Rear Track Compressed Length 15.610
Rear Track Travel 6.070
Air Spring Pressures Front Track Main – 35psi
Rear Track Main – 145psi
EVOL – 280psi

Also Fits

Lynx Boondocker DS 3900 2022 Rear $1,599.99
Lynx Boondocker DS 4100 2022 Rear $1,599.99
Lynx BoonDocker DS 850 E-TEC 3900 2022 Rear $1,599.99
Lynx BoonDocker DS 850 E-TEC 4100 2022 Rear $1,599.99

have a look at other products


Go to Top