Optional Coil Conversion Kits

Hybrid Coil/Air Open Bath Cartridge Damper System

Hybrid coil requires our open bath cartridge damper system as a starting point.

Equal force system Technology

Add option here
Hybrid Coil/Air system

Are you having trouble setting your sag on your air fork and not getting full travel?

Hybrid coil/air cartridge damper system

This is the key to a plusher more coil like feel because
the spring rate is not over sized compared to coil only MTB coil forks.

The reason you have to play with spring rates to get the best compromise is the reason you need ramp up through the
entire stroke, ramp up allows you to run much softer spring creating a plusher feel and
increased bottoming protection. In other words the lack of ramp up forces you to an over sprung system.

Think of the fork as creating 3 almost equal separate forces to create a properly uncompromised suspension.
1.damping force, 2. spring to support your weight at proper sag and preload, and 3. ramping to increase the spring
rate as it gets deeper in the travel. If the damping is missing(compression open or all the way out) then it needs to be
over sprung or more ramp up is need to come up with a compromised solution. If the ramp
up is missing then the damping or spring needs to be over done for a compromised solution

This 3 part solution is what all forks have been using for 50 years, only MTB suspension tries to eliminate 1 of the 3
or 2 of the 3 parts for lighter weight and reduced cost.

How can we better make a coil fork even better!

A little history as to how this happened:

 The original or traditional coil forks were
designed for MX and the early MTB forks with a damper and spring in each
side, filled about 2/3’s with oil. This allowed the fork to create a coil
spring like feel for the first half of the travel. The air space above the oil
is compressed which produces an additional spring force in the last half of the
travel. This additional air spring effect does two things, it allows the
selected coil spring rate to be much softer because the air supplements and
increases the spring rate and the ramp up or progression can still be
controlled by the air volume compression by changing the oil height.

 MTB forks eliminated one damper to save
weight and reduce the cost to produce over the past 20 years and used a single
long over rated spring with no oil in the coil leg. This led to an air spring
version that emulates a coil to further reduce the  weight.
 This is essentially is where we are now with
your typical air spring system single damper front fork.

 Our hybrid coil conversion brings back the
ideal coil/air spring system without the added weight of traditional spring/oil
filled fork. The air side is still used to create the additional spring rate
and ramp rate at a much lower pressure. We use our open bath damper with a
lighter and shorter coil spring on top of it. The air spring side remains
unchanged and creates the additional spring rate. The air side now uses about
1/3-1/2 of the pressure that you currently used to create the additional
spring rate which can be adjusted to support your weight and ramp up desired.
 This hybrid system works in conjunction with
our open bath custom valved damper with our exclusive midvalve and high speed
blow off system (FvAT/HSB). Our damper creates a very supportive compression
system that prevents fork dive and still feels plush on small bumps. This
midvalve system and base valve will still blow off to prevent deep square edged
harshness without bottoming.


How our customer describes this system, "Motocross forks utilize a combo of coil and air (they use oil volume to adjust air pressure progression) because it tends to work the best. You get a fork that isn't initially too soft/ divey and a well supported mid stroke due to the coil and then you get the progression needed at the end to prevent harsh bottom outs. No doubt a hydraulic bottom out works as well but then you might lose some other benefits of a hybrid setup, mainly spreading the spring force between both legs so that they work in better harmony. With all the spring force in one leg of a mountain bike fork some have reported notably different amounts of travel being used by each fork leg due to the flex."

The hybrid coil kit supports about half the rider weight and the air spring makes up for the other half of the support needed. Now the air side can be used to fine tune the spring rate needed as well as adjust the ride height for different riding conditions, also the air ramp-up can be controlled with the traditional tokens or aftermarket ramp up adjustment devices. The advantage of the hybrid system is versatility, performance, weight, and cost savings. It simply drops on top of our open bath damper side, only adds about 180 grams(250 grams for 8 inch fork), it solves most of the air spring issues in the first half of the stroke, where the friction forces and small bump compliance are critical, more supportive, it fills in the midstroke wallow of the air spring and corrects the ride height with physical adjustable preload. When the fork gets deeper in the stroke the spring force is more dominant and the stiction and air spring concerns are not as noticeable, so the final spring force is not as sensitive as long as it is more linear and removal of the tokens is now possible with proper damping. The air spring can be set to very low pressures and as linear as possible where it is nearly negligible. Ride height and spring rate can be fine tuned with the air spring pressure which is very helpful when in between spring rates and allows for different riding conditions. The equal force system is a very important feature because now the fork compresses equally with about the same spring rate in both stanchions, a single spring system causes the unsprung side to compress ahead the spring side because of the flexibility of the crown and lowers, this causes stiction in the first half of the travel which is more of a contributor than the air spring stiction. The abs system that we sell as an option to our damper is not necessary because of the air hybrid ramp up is sufficient to prevent bottoming.

Hybrid Coil and Open Bath Damper System

Hydraulic ABS is not required for bottom-out protection but will improve deep square edged performance if used in lieu of air rampup.

Only available as an open bath cartridge system option.

Available for Fox 40 Float (203/190), Boxxer WorldCup(203/180), Fox 38 (150/160/170),Fox 36/Z1 Bomber(180,170,160/150/140), Zeb (150/160/170,180)
MRP, Pike 29er (2014-17) 150, Lyrik/Yari (160/150/140 limited to riders under 210lbs)



Single Crown Forks

Hybrid Coil/Air Option

Fox 36/Z1 Bomber(180/170/160/150/140)

Fox 38 (150/160/170)

Zeb 38 (150/160/170/180)

MRP 160/150/140 mm limited to riders under 220lbs

Lyrik/Yari (160/150/140) limited to riders under 220lbs

Download: Hybrid Coil Air Cartridge Installation and Set-up Manual beta(3 MB)

Keep in mind the required spring rate for heavier riders can still be achieved
with a combination of the coil and air spring, but the hybrid affect will be lessened
(the coil like feel will be less as more air pressure is required to make up for the spring rate needed)


Choose rider weight.
Rider weight is without gear, we add 5-7 lbs for DH gear, 7-10 lbs for All-Mtn/Freeride.

Rider Weight


Fork Travel

Fork Travel

Only available when orfered with the open bath cartridge system option

Price $199 single spring system

The second additional spring will cost aditional $99 for heavier rider option only avaiable on some models, call or e-mail for assistance.





Dual Crown Forks

Fox 40 Float, Fox 49, Bomber 58 (203/190), Boxxer WorldCup(203/180)

Download: Hybrid Coil Air Cartridge Installation and Set-up Manual beta(3 MB)



Choose rider weight.
Rider weight is without gear, we add 5-7 lbs for DH gear, 7-10 lbs for All-Mtn/Freeride.

Rider Weight

Fork Travel

Fork Travel

Only available when orfered with the open bath cartridge system option

Price $259 single spring system