Vorsprung FOX A2 Secus Fork Air Spring Upgrade Kit Installation Guide

Vorsprung FOX A2 Secus Fork Air Spring Upgrade Kit

TOOLS REQUIRED

NOTE: Do not proceed unless you have the following tools and supplies on hand.

•  10mm shaft clamps
•  Torque wrench
• Torque wrench to spanner adapter
• 12mm spanner
• 11mm socket
• Slickoleum (Slick Honey) grease
• Red Loctite
• Secus Body
•  Secus Footstud
  • Also containing:
  •  Installation tool
  •  Footnut
  •  3x additional foodstud o-rings (as spares, in case of damage during assembly)
  • 5mm grey aluminium spacer (not pictured)

ASSEMBLY

There are 3 main sections to installing the SECUS

• PART 1 – Replacing the stock footstud from your fork
• PART 2 – Installing and positioning the Secus on your fork
• PART 3 – Inflation & equalization process

PART 1 – REPLACING THE STOCK FOOTSTUD FROM YOUR FORK

1.  See manufacturer’s service instructions for disassembling the stock air spring and removing it completely from your fork.
   Refer to the relevant factory service instructions up until you have removed the air spring from the stanchion.
   FOX: https://www.ridefox.com/fox17/help.php?m=bike&listall=service
   Refer to the factory service instructions for torque specifications, lubrication specifications and general disassembly/reassembly.
   

2. Secure shaft firmly using 10mm shaft clamps. Ensure you are not clamping too close to the foot stud and potentially onto the threads internally, allow approx 1 inch/25mm.

3. Heat area with heat gun. Remove foot stud from shaft using 12mm wrench or knipex, do not use multi grips.

4.  Clean Loctite residue from shaft thoroughly, particularly from seal gland that could poten-tially compromise the seal on foodstud

5. Place a drop of red Loctite onto Secus foot-stud thread. Do not get any on the o-ring. Thread it down onto the shaft by hand

6. USE A TORQUE WRENCH. Torque using open-ended wrench & adaptor attachment on the wrench, or 12mm crows foot attachment avail-able from the hardware store. Torque to 40in.lbs or 4.4Nm. Ensure torque wrench is 90 degrees from wrench as shown.

7. See manufacturers’ service instructions for re-assembling the air spring & your lowers.
   FOX: https://www.ridefox.com/fox17/help.php?m=bike&listall=service
   Refer to the factory service instructions for torque specifications, lubrication specifications and general disassembly/reassembly.
   Refer to the relevant factory service instructions up until you have torqued the damper side and you are ready to torque the spring side.
   Note: Place an additional 5ml of oil in the spring side.
   

8.  When spring side is filled with oil & ready to torque, note the protrusion of foot stud. The third o-ring should be barely sticking out from the lowers. Use installation tool (plastic cylindrical spacer) to pull the shaft through into the lowers & engage the press-fit.

9.  Place installation tool over footstud & wind down nut. Use an 11mm socket to pull the shaft through until you feel minor resistance. Don’t do it up tight. Remove installation tool.

PART 2 – INSTALLING THE SECUS BODY

1. Ensure o-rings are lubricated on foodstud with Slickoleum (also sold as Slick Honey, SRAM Butter etc).

2. Slide 5mm grey spacer over footstud. Then slide Secus body over footstud. Place footnut on by hand.

3. Use a torque wrench to torque the footnut to 50in.lbs (5.6Nm) in order to fully seat the assembly. Do not exceed 50in.lbs or you will break things. DO NOT tighten without a torque wrench or you will break things.

4. Install the fork back onto your bike at this stage. Also install your front wheel & ensure brake caliper is aligned as per normal.

5. Slightly loosen the footnut so Secus body can rotate. Position the Secus close to the brake mount, ideally with a 2mm gap.
   Note: if you leave less than 1mm gap, the flex in the system may mean that the Secus can rattle against the caliper.

6. Using the torque wrench, torque to 50in/lbs (5.6Nm) whilst holding the Secus in place. You can loosen the footstud at any time to relocate it – the rotational position does not matter for function, only for clearance and minimising protrusion of the Secus.

PART 3 – INFLATION & EQUALIZATION PROCESS

1. It is recommended that you inflate to 20% higher pressure to what you previously ran, as a starting point. You may wish to run more or less pressure than this – it is only a starting point. At this point, the fork will be extremely stiff and it will be topping out hard – this is normal.
2. Push down slowly onto fork to equalize (this will be difficult – you can do it at a lower pressure initially). You will hear a hissing sound as the air from the positive chamber passes through the ports into the negative chamber. As this occurs, the pressure in the positive chamber will drop.
3. Continue the process of adding more air & pushing down again to equalize the fork pressure to your desired pressure.
4. Push the GOLD button on the bottom of the Secus. This charges the Midstroke Support Valve with the correct amount of pressure. It only needs to be pushed once, but pressing more times won’t alter anything. If you are changing pressures (up or down), be sure to push it.

Tuning your fork with air volume tokens

See below for recommended starting points for setting up your Secus with air volume tokens. Add one volume spacer for e-bike fitments.

THIN GS TO NOTE:

Deflation/ depressurization
If you are fully deflating the fork, ensure the gold button is held down while releasing air slowly from top cap. This will ensure the negative chamber is fully discharged while depressurising.
If the fork sucks down more than 20mm while depressurising, that means the air piston has come past the equalization ports too fast and air is still trapped in the negative chamber, unable to equalize and escape via the positive chamber. In this case, re-inflate the fork (or forcibly ex-tend it by placing your foot on the wheel and pulling on the bars), re-equalize it, then let air out more slowly.

NOTE: You must depressurize the fork fully if you wish to take the lowers off. Do not remove the lowers without depressurizing the air spring.

Flying with your Secus
Pay special attention when boxing/bagging your bike – ensure the fork is supported by the axle and not resting on the Secus when flying.

Be aware – there is now an additional part on your fork.
Please do not lean the Secus on the floor (especially while the front wheel is off, or if you are packing your bike into a box), or against anything. Likewise, be careful when carrying the bike on a truck tailgate – ensure the Secus is not contacting the bumper or other bikes.

12 Month Crash Replacement Guarantee
We will replace any damaged parts of your Secus in the event of a crash or accident for the first 12 months of ownership, free of charge. Just send through pictures to the email below so we can help you ascertain which parts require replacement.

Questions?
Email: steve@vorsprungsuspension.com
www.vorsprungsuspension.com

References

• Engineered Suspension – Vorsprung Suspension
• Bike Help Center | FOX

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