2014-2015 40 FLOAT- Changing the Air Spring Compression Ratio

Supplies Needed

  • 5mm Hex Wrench
  • 6-point Chamfer-less 32mm Socket
  • 6mm Hex Wrench
  • Torque Wrench

The 2014/2015 40 FLOAT uses a simple air chamber volume adjustment system as part of the air topcap assembly. By switching the position of internal spacers to change the location of the compression bulkhead on the shaft, nine different compression ratios are available.  The stock position for the compression bulkhead is in the middle (3.04 compression ratio).

  • Increasing your forks compression ratio will make your air spring curve more progressive.
  • Decreasing your forks compression ratio will make your air spring curve more linear.


Use the following instructions to change your 2014/2015 40 FLOAT air spring compression ratio.

Keep the fork upright during this entire procedure to prevent the loss of any fluid from the air chamber.


Step 1

Remove the blue air cap and cover the air valve with a rag as you release the air pressure.



Step 2

Loosen the 5mm hex bolt on the rider's left side of the upper crown.



Step 3

With a chamfer-less 6-point 32mm socket, unthread the topcap assembly completely. Pull straight up to remove the entire topcap assembly from the left side stanchion tube. Some upward force might be needed to overcome the friction of the o-ring on removal.



Step 4

While holding the topcap with the 32mm socket, use a 6mm hex wrench to unthread the black anodized bolt from the end of the shaft. If the topcap unthreads from the shaft rather than the black anodized bolt, clamp the shaft in your 10mm shaft clamps and re-torque the topcap to 45 in-lb (5.1 Nm) after cleaning the threads and applying a drop of red Loctite 262.



Step 5

Remove the spacers and the compression bulkhead from the shaft assembly.



Step 6

Position the spacers and the compression bulkhead (flat side of bulkhead facing away from topcap) in the desired order to acheive your desired compression ratio. 

  • Moving the compression bulkhead closer to the topcap will decrease your compression ratio.
  • Moving the compression bulkhead farther from the topcap will increase your compression ratio.


Step 7

Reinstall the black 6mm hex bolt and torque to 30 in.-lb (3.4 Nm) while holding the topcap with your 32mm chamfer-less 6-point socket.



Step 8

Smear a thick coating of Float Fluid around on the inside of the first 2 inches of the upper tube.



Step 9

Coat the o-ring and the compression bulkhead with a film of Float Fluid and install into the stanchion tube. Push the topcap assembly into the stanchion tube while holding the air valve core down to release any trapped pressure.


40 FLOAT maximum air pressure is 100psi


Step 10

Torque the topcap to 220 in.-lb (24.8 Nm). Torque the upper crown bolt loosened in step 2 to 65 in.-lb (7.3 Nm). Add air pressure to your fork to your previous air pressure setting and replace the blue air cap.


WARNING: Modification, improper service, or use of aftermarket replacement parts with FOX forks and shocks may cause the product to malfunction, resulting in SERIOUS INJURY OR DEATH. DO NOT modify any part of a fork or shock, including the fork brace (lower leg cross brace), crown, steerer, upper and lower leg tubes, or internal parts, except as instructed herein. Any unauthorized modification may void the warranty, and may cause failure or the fork or shock, resulting in SERIOUS INJURY OR DEATH.

WARNING: FOX suspension products contain pressurized nitrogen, air, oil, or all 3. Suspension misuse can cause property damage, SERIOUS INJURY OR DEATH. DO NOT puncture, incinerate or crush any portion of a FOX suspension product. DO NOT attempt to disassemble any portion of a FOX suspension product, unless expressly instructed to do so by the applicable FOX technical documentation, and then ONLY while strictly adhering to all FOX insturctions and warnings in that instance.

WARNING: FOX products should be serviced by a qualified bicycle service technician, in accordance with FOX specifications. If you have any doubt whether or not you can properly service your FOX product, then DO NOT attempt it. Improperly serviced products can fail, causing the rider to lose control resulting in SERIOUS INJURY OR DEATH.

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