Fox vs King 2.0 Coilover: Find Out Who Makes the Best Shock

February 11, 2016

When choosing between Fox 2.0 Remote Reservoir Coilovers and King 2.0 Remote Reservoir Coilovers, the differences extend far beyond the color of their anodizing. To provide a comprehensive comparison, we evaluated the real-world performance and durability of each coilover, helping you make an informed decision. Our test included a Fox 2.0 x 14? Travel Factory Series Remote Reservoir Coilover and a King 2.0 x 14? Travel Performance Series Remote Reservoir Coilover—two of our most popular off-road shocks.

King 2.0 Coilover, Remote Reservoir – 14″ Travel
From: $523.00

Starting at $48/mo or 0% APR with Affirm. See if you qualify

External:

Externally, significant differences impact value, appearance, and durability. Both shocks feature 1/2? ID COM-8T Teflon-lined bearings, plastic dual-rate sliders, aluminum remote reservoirs, and anodized aluminum caps. However, the Fox 2.0 Coilovers use a -8 stainless steel braided hose, while King uses a -8 cloth-wrapped hose. Additionally, Fox includes remote reservoir mounts, which are not provided with King coilovers.

Durability:

Durability is important for shocks on off-road vehicles. We will be focusing on piston rods, seals and oil quality.

Piston Rods:

Fox 2.0 Factory Series coilovers use 17-4 H900 stainless steel piston rods with hard chrome plating, offering superior corrosion resistance and strength (190 ksi tensile strength). King 2.0 Performance Series coilovers use chromoly steel piston rods, which are not heat-treated for surface hardness. Fox rods have a Rockwell hardness of 45 HRc, compared to King’s 23 HRc, providing substantial durability advantages against rock debris.

[layerslider id=”13″]

Seals:

Fox 2.0 Factory Series coilovers come with Viton seals, ideal for high temperatures and low friction. King uses industry-standard Buna seals, with Viton seals available as an upgrade. Fox’s multi-layer sealing system offers extra protection against dirt intrusion, enhancing longevity.

Oil:

Fox shocks use oil rated for temperatures from -65 to 275°F, with a viscosity index (VI) of 370, ensuring exceptional performance. King’s oil is rated for 14 to 230°F, with a VI of 150. Fox oil provides better lubrication across a broader temperature range, reducing the likelihood of shock failure.

Performance:

Friction

Low friction is crucial for vehicle suspension. Fox 2.0 Coilovers and King 2.0 Coilovers both manage friction well, with Fox having a slight edge due to superior component quality.

Rebound Damping:

Both coilovers offer excellent rebound damping. Fox uses 2 x .070? bleed holes, and King uses 3 x .056?, with no significant performance differences observed.

Compression Damping:

Both shocks provide linear damping curves essential for off-road performance. Fox’s higher nitrogen pressure (200 psi) compared to King (150 psi) improves resistance to cavitation, enhancing control and durability.

It is important for off-road shocks to provide a linear damping curve and to have very little hysterisis in the curve. Linear damping with pyramid stacks (decreasing OD through stack) gives control of the damping curve to the shock tuner to build progressive rate flutter stacks for improved feel over small bumps and hard hits. Both Fox 2.0 Coilover Shocks and King 2.0 Remote Reservoir Coilovers provide good, linear, consistent damping as you would expect from a high quality race shock. In the graph below, the shock starts making 40 lbs of force at 0 IPS (left side, top lines), and increases to 520 lb of force before slowing back down to 0 IPS and making -5 lb of force.

It is important for shocks to resists cavitating on high speed events because cavitation leads to a loss in control and can damage the shock. Cavitation is a function of remote reservoir ID and nitrogen pressure. Fox 2.0 Coilovers and King 2.0 Coilovers have nearly the same ID (1.813 vs 1.750, respectively) but Fox recommends 200 psi and King recommends 150 psi. The increased pressure in 2.0 Fox coilovers results in improved resistance to cavitation. It is possible to run higher pressure in 2.0 King coilovers but higher pressures increase friction and seal wear.

[layerslider id=”13″]

Factory Tuning Limitations

While both pistons are capable of providing excellent performance King has limited tuning options. King will only build a pyramid stack (decreasing OD through stack) and add one flutter disk. While a single flutter disk is industry standard, and we used to tune that way (and still do in the rare instance it delivers the desired performance), we’ve found that a single flutter disks does not give you full control of the damping curve. We use AccuTune double flutter stacks which deliver vastly superior comfort on small bumps and more speed in the whoops. As a result we pull apart every Fox and King shock and re-valve it in house.

Summary:

Both Fox and King build durable, high-performance coilovers that surpass conventional sealed monotubes. However, Fox stands out with superior durability in piston rods, seals, and oil. Neither shock offers optimal performance out-of-the-box without re-valving, but with proper tuning, both can enhance your off-road experience. Whether you’re equipping a daily driver or a race truck, we can help you select and tune the right shocks to maximize the potential of your Fox 2.0 Coilovers or King 2.0 Coilovers.