FOX vs KING
OEM FIT COILOVERS

“What’s the difference between Fox and King?” We get this question a lot and this article we will help explain some of the main differences between the two brands. This article is intended to educate, and allow YOU as the customer to make the best decision for your budget, build and lifestyle.

*Before reading, the coilover examples we will be referencing are:

Vehicle: 2016+ Toyota Tacoma
Shocks:
Front Extended length coilovers (most common)

Fox 2.5 Coilover, Remote Reservoir 0-3” Extended length with DSC (FOX-880-06-418)
Compressed Length: 17.59″ | Extended Length: 22.48″


King 2.5 Coilover, Remote Reservoir 0-3” Extended length with Adjuster (KRS-25001-119A-EXT)
Compressed Length: 17.3″ | Extended Length: 22.6″

Springs

FOX: Silver color. Eibach has a full line of silver springs if new rates are needed. They use a high quality wire & manufacturing. Heavier rate springs need to be purchased separately.

KING: Blue color. Blue replacement springs are available from King. Silver Eibach springs also fit and look great. Shocks can be special ordered with heavier rate springs for no additional charge.

Shock Body

FOX: Steel Body, Zinc plating

KING: Steel Body, Cadmium plating

Notes: Both have similar corrosion resistance.

Shafts / Piston Rods

FOX: 17-4 H900 Stainless Steel, Surface Hardened, 45 HRC 
KING: 1045/1050 Steel Chrome Plated, Through Hardened, 23 HRC

Notes: A shock leaking oil is one of the most common issues we encounter with customers. This is usually due to a damaged shaft which then cut the seals. Surface hardening helps prevent the piston rod/shaft from being damaged after being hit with sand or rocks. The Fox Stainless Steel shafts are twice as strong as Kings and will take more abuse.

HRc is a measure of hardness on the Rockwell C scale. Hardness is measured by pressing a ball into the material at a preset force. The further the ball deforms the metal the softer (lower) on the scale it registers.

Pistons

FOX: Linear 
KING: Linear. However some shocks do come as Digressive, but we revalve them to be  linear. 

Shock Seals

FOX: Buna
KING: Buna & Urethane
Notes: Both shocks use a high quality urethane wiper. Fox uses two Buna main seals. King uses a main Buna o-ring and urethane secondary u-cup. The King sealing package is much higher friction which can cause issues with ride quality. To mitigate the high friction King charges their shocks to 150 psi, which can cause issues with cavitation.

Shock Oil

FOX: Conventional Oil, rated up to 400F, viscosity index of 370
KING: Conventional Oil, rated 14 to 230 F, viscosity index of 150

Notes: Fox oil offers substantially better lubrication across a wide range of temperatures, and is less likely to break down due to heat. High lubricity and resistance to breaking down are critical for a long lifespan. Viscosity index (VI) is a measure of how much the damping will fade due to heat.  Fox’s VI of 370 is very high and provides exceptional performance.  King’s VI of 150 is an average rating which means it is much more prone to shock fade when getting hot.

Bearings & Bushings

FOX: Fox coilovers use bearings top and bottom from FK Rod Ends. These bearings are sealed with an o-ring for increased durability. OEM fit smoothie shocks mainly use bushings.
KING: All of King Shocks use bearings except for stud mounts. 

Notes: In corrosive environments bushings are a lot more durable and can easily be replaced. In racing environments the bearings are more durable.

Internal Top Out

FOX: At full extension the Fox shocks have a rubber top out bumper that prevents hard metal to metal contact. This rubber bumper makes the shocks quieter and smoother, and is a noticeable improvement when lifted two or more inches.
KING: At full extension, Kings internal stops are metal on metal. Although this doesn’t not harm the shock, it can be noticeable when the shock tops out.  

Remote Reservoir Hose Fittings

FOX: -6 hose fittings, using hard 90s and soft 90 degree fittings.
KING: -6 hose fittings, using hard 90s and soft 90 degree fittings.

Notes: Bigger hoses flow more oil and ride better. -6 hose is adequate for this application.
(
-6 Hose Fitting = 3/8″ Tube ID)

Remote Reservoir Hoses

FOX: Black cloth wrapped hose
KING: Blue/rubber with white/label writing

Notes: No real difference in strength. King hose is easier to manipulate and mount the reservoir.

Reservoir Mounts

FOX: Yes, mounts using OEM bolts. Black powdercoated

KING: Yes, mounts using OEM bolts, silver finish with zinc plating

Shock Adjusters

FOX: DSC, Dual Speed Compression adjuster. Allows you to manually adjust the high speed and low speed compression. [TECH about DSC Adjusters]

KING: Mid Speed Adjusters. One knob to adjust mid speed compression.
[TECH about King Adjusters]

Rebuild Kits and Parts

FOX
Rebuild Kits Viton: $19 / Buna $17
Fox Shock Oil (1 Gallon): $65
Replacement Shafts: $79
*Prices as of 5/1/2020

KING
Rebuild Kits Viton: $32 / Buna: $25
King Shock Oil (1 Gallon) : $35
Replacement Shafts: $75
*Prices as of 5/1/2020

Accutune Offroad can rebuild or repair most Fox & King shocks, click here for pricing

Shock Tuning

Both Fox and King OEM Coilovers come standard with soft valving that tends to be bouncy and handle poorly. This may work ok for a mostly stock vehicle with no additional upgrades, but we feel there is room for improvement. Depending on what vehicle you have, and how you plan on driving it, we can work with you to valve the shocks for the ultimate performance.

If you are interested in having you Fox or King Shocks custom valved, contact us today to learn more (424) 377-0808 | Sales@Accutuneoffroad.com

SUMMARY:

Both Fox and King have great products to offer the OEM market. Most of their OEM shocks can be tuned, rebuilt or upgraded. Rebuild kits are usually stocked by suspension shops or can be easily acquired from the manufacturer.

So what are some things that would make you pick one over the other?

Fox is considered one of, if not the largest shock manufacturer in the off-road industry. They build shocks for everything from Mountain Bikes, Snowmobiles, UTVs, and Trophy Trucks to Factory options on trucks like the Ford Raptor & Jeep Rubicon.

Compared to other shocks, Fox uses better seals, shock oil and shafts, but are considered one of the more expensive options on the market. However, with price comes quality and you “get what you pay for”. The Fox shafts are more durable which will prolong the life of the shock. The surface hardening on these shafts are ideal for areas that may see harsh winters with snow/salt on the roads. Shock seals like clean and undamaged piston rods. In addition to the high quality materials Fox uses, their DSC Adjuster is one of the most advanced shock adjusters on the market. For towing or fine tune adjustments, the DSC Adjusters are a great feature to have.

King Shocks is one of the most well known shock brands in the off-road industry. They are Family Owned & Operated – 100% Designed, Manufactured & Assembled in the U.S.A since 1996. Their high performance shocks can be found on top tier race trucks all over the world. King offers a great variety of OEM fit high performance shocks at a reasonable price. These shocks look great, can be tuned, rebuilt and upgraded to fit your needs.

King carries over most of their race parts to their OEM line so your daily driver can have a touch of trophy truck technology. Their anodized blue components definitely stand out and look amazing. If you want the coolest off-road shocks look no further than King.

As you can see from this article there are some differences between the brands, and both are great choices with the AccuTune magic inside.

Related Tech Articles

Fox vs King 2.0 Coilover Shocks

How King Adjusters Work

How DSC Adjusters Work

Should I Get DSC Adjusters?