JBI Fork Volume Spacer Set

JBI Fork Volume Spacer Set

• Fork volume spacer is used in place of adding oil to fork outer chamber
• Independently tunes the fork internal volume without changing the spring seat (aka spring perch) engagement point with the fork outer chamber oil
• Tuning the fork internal volume changes how progressively the forks build up compression resistance when being compressed
• Doing so maintains a smooth feeling fork with strong progressive bottoming resistance
• Mounts above the fork spring seat aka spring perch
• Manufactured from specialized NBR rubber and stainless steel springs
• Advantageous for Motocross and Off-Road setups
• Can be used with stock spring seat or JBI Pro Perch 2.0 and JBI Ti Pro Perch

JBI Fork Volume Spacer Tuning Info (KYB SSS 48mm & Showa 49mm Twin Chamber Forks)

• Motocross oil volume range: 310-345cc
• Recommended starting point is 330cc
• Off-Road oil range: 290cc-330cc
• Recommended starting point is 310cc
• 345cc maximum fork outer chamber oil volume when using the JBI Fork Volume Spacer

Why develop the JBI Fork Volume Spacer?

Testing and rider feedback has shown riders favor an oil volume between 300-345cc with the stock oem spring perch or JBI Pro Perch even though the maximum fork volume capacity is 400cc.
When fork oil volumes are above 350cc the forks begin to provide additional compression resistance too early in the fork travel making the forks feel less comfortable.
To maintain fork oil volumes below 350cc and maintain a preferrered spring seat engagement point the addition of the JBI Fork Volume Spacer allows for independent tuning of the forks internal pressure build up.

The affects of changing outer chamber oil volume on twin chamber forks

   1.   Adding / Subtracting oil volume in the fork outer chamber affects how much internal pressure builds up inside as the fork compresses down reducing volume.

• More oil = more internal pressure & more bottoming resistance
• Less oil = less internal pressure & less bottoming resistance

    2.  Adding / Subtracting oil volume in the fork outer chamber changes the engagement point when the fork spring seat / spring perch engages the fork outer chamber oil.

• When the fork spring seat engages the fork outer chamber oil this results in additional compression resistance (aka bottoming resistance) as the oil must be forced / pushed through the spring seat holes.
• The more outer chamber oil volume the sooner the fork spring seat will engage the oil = more bottoming resistance
• The lesser outer chamber oil volume the later the fork spring seat will engage the oil = less bottoming resistance

Explain it like I am 5
Above a certain oil volume adding oil to the fork outer chamber to achieve more bottoming resistance (this is good) is equally diminished by the harshness & loss of fork comfort (this is bad).
The JBI Fork volume spacer allows for independent tuning of the fork internal volume so the fork oil volume and spring seat engagement point may be optimized to provide the smoothest ride and fork feel while still having strong bottoming resistance. 

JB Suspension Fork Volume Spacer Info Video

JBI Suspension Fork Volume Spacer How to install video

11.13.24

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