February 11, 2021

Bypass Shocks PART 1

  • How do Bypass Shocks Work?
  • Shock Zones & Basic Tube Layout
  • Bottom Take Off Reservoir

Bypass Shocks PART 2

  • Off the Shelf Options
  • Multiple Compression and Rebound Tubes
  • Staggered vs Overlapping Tubes
  • Piggyback vs Remote Reservoir

Bypass Shocks PART 3

  • Customizing Bypass Shocks
  • Custom Setup Recommendations
  • Shock Diameter
  • Tube Layout around body
  • Tube Heights & Diameter
  • Coatings, cooling and color options

Bypass Shocks PART 4

  • Fox vs King Comparison
  • Check Valve Design
  • Pistons
  • Bypass Adjusters Screws
  • Piston Rods
  • Oil Seals

Bypass Shocks PART 5

  • Bypass Shock Setup
  • Up Travel
  • Motion Ratio – Coilover & Bypass
  • Total Weight
  • Weight Distribution (front/rear)
  • Unsprung Weight

Tube Height Location

Off the shelf bypasses are almost all set up to run 50% of the shaft showing at ride height (eg: 7” of shaft showing on a 14” travel bypass shock). If you have too much shaft showing the ride zone will be too large and the shocks will be soft and bouncy. Conversely, if you have too little shaft showing the shock may be past the ride zone on compression and possibly even rebound. Riding with the piston in the transition zone or bump zone is a huge issue because there likely won’t be enough oil flow through the bypass tubes in order to tune the shocks to be soft enough. Shocks riding with too little shaft showing also frequently experience harsh transitions into the bump zone because each zone doesn’t have enough room to work. By customizing the tube heights we are able to make sure the shock is riding in the correct zones and is not too stiff or too soft. 

Tube Layout & Diameter

Tube layout (staggered vs overlapping) and diameter are tied together because both impact how much oil can flow in the ride zone. Shocks with not enough flow can be very rough in the chop, or downright neck breaking in the whoops. By getting the correct size bypass tubes, there can be huge improvements in the comfort and performance. Due to the variety of vehicle specs and setups there is not always a one size fits all answer, but more flow is almost always better. When we work with customers on a custom bypass shock, we always request overlapping tubes to get the most out of the shock.

Shock Diameter

Shocks can be too small and too big. Shocks have a range of forces where they are happy, there is a minimum and maximum amount of damping. When bypass shocks are significantly too small they can’t make enough force, resulting in them being too soft and bouncy. In this scenario the tubes will likely be near fully closed, making them expensive smoothies. When shocks are a little too small and they need to make near their maximum stiffness, tunability is reduced and they will become harsh in ways that can’t be tuned out. In the opposite manner when shocks are too big they need to be tuned near their minimum amount of damping. If that minimum amount is still too stiff the ride can be very rough and jarring.

Tube Orientation

It is very common for the standard tube orientations to have clearance issues with other items on the chassis or suspension. These issues can be compounded when ordering larger diameter tubes. All of the Fox and King bypass shocks can be ordered with custom tube orientations in order to optimize the fitment.

Shock Cooling

Usually when your shocks need more cooling it is time to step up in diameter. But that is not always possible due to stiffness issues, or clearance issues. In these cases it makes sense to install external oil coolers. King offers large finned reservoirs which do help on piggyback shocks. Fox offers the Baja cooler which uses the rebound bypass circuit to flow oil in a single direction through a dedicated cooler, and the results are impressive. The Fox system can be adapted to other brands as well.

Shock Coatings

King bypass shocks come standard with cadmium plating and Fox uses Zinc plating. Both coatings have similar corrosion resistance and don’t hold up well in corrosive environments. Luckily both Fox and King offer Cerakote. Cerakote is a very thin, very hard ceramic coating which is baked on to the shock body. Cerakote looks great and stands up to harsh environments.

Custom Shock Colors

King bypass shocks are available with custom colors. Custom color means that all of the aluminum anodized parts are stripped and recoated in the new color. While you can pick the color, you can’t pick the exact shade. Fox Bypasses are only available with their standard black anodizing.

  • Off the shelf options
  • Multiple compression and rebound tubes
  • Staggered vs overlapping tubes
  • Fitment & installation

  • Fox vs King Comparison
  • Check Valve Design
  • Pistons
  • Bypass Adjusters Screws
  • Piston Rods
  • Oil Seals