FORK SPRING PRELOAD - DAMPING ROD
and External Top-Out Spring Cartridges

Recommended Preload is available in Product Search or on your DVS Setup Sheet if you are using Gold Valves.

Dirt bike preload ranges from 4-6mm. Fork preload is NOT a tuning variable. Too much preload will make the ride harsh particularly on acceleration bumps.

Street bike preload ranges from 5 to as much as 35mm. Preload can be used to affect ride height and chassis geometry. It can also temporarily be used for increased loads however this is best done with spring rate.

Preload can have a huge effect on the feel of the fork so make sure you look it up on the DVS Setup Sheet or Product Search.
 

Click to enlarge

1 - EXTERNAL TOP-OUT SPRING FORKS
 
  • These instructions cover all External Top-Out Spring Forks
  • "External top-out" means external to the damping rod or cartridge tube
  • Includes all Damping Rod Forks
  • Some right side up Cartridge Forks are this type
 
 
 
2 - TOOLS AND SUPPLIES
  • Tape measure (metric)
  • Tubing cutter for spring preload spacer
  • Preload Spacer material
  • Steel Spring Washers
METHOD #1

3 - Setting the fork spring preload is done by making the correct length preload spacers.

1. If your forks have Preload Adjusters set them to minimum.
 
2A. If you have a damping rod fork with an Emulator. Install the Emulator Adapter first if required. Drop the Emulator down the tube. It sits on top of the damping rod (or Adapter) with the Emulator Valve Spring facing up and is held in place with the main fork spring. Visually check to make sure the Emulator is sitting squarely on top of the damping rod or the Adapter.
 
2B. If you have an external top-out cartridge the cartridge rod does not need to be attached to the cap for this process.
 
3. Extend the fork tube all the way.
 
4. Insert the fork springs into the fork tube. (On top of the Emulator if used.)
 
5. Install a steel fork spring washer.
 
6. Install the fork spring spacer tube. Any length that goes above the top of the fork tube is ok for now.
 
7. Install another steel fork spring washer.
 
8. Set the fork cap on the washer.
 
9. Measure from the top of the fork tube to the sealing lip on the fork cap. This is a direct measurement of fork spring preload.
 

Direct Measure of Preload (THIS ONE HAS WAAAAY TOO MUCH)
 

10. Adjust the spring spacer tube length to achieve the proper preload.
 
In this example using the image above:
If you are looking for 15mm preload you would shorten the spacer by 46 - 15 = 31mm
 
NOTE: You must have steel washers on both ends of the spacer. The spacer must not rest directly on the spring or the cap.
METHOD #2

4 - If the preload is small the thread on the cap will hit the thread in the fork tube before touching the washer.

 

 Measure from the top of the fork tube to the Steel Spring Washer.

In this case 11mm.

5 -  Measure the Fork Cap Height

In this case 18mm. (The fork cap is upside down)

Calculate the Preload

(Fork Cap Height) - (Top to Washer) = Preload

18 - 11 = 7mm Preload

Adjust the Spacer Length or add washers to get the recommended Preload.