Coil Conversion Kit / Option

Dual Coil ABS
Equal force system



One spring sits inside the positive air chamber using the stock air cap with adjustable preload.
The other spring sits on top of the open bath damper hydraulic ABS system in the damper leg.
The air shaft system provides the support for the spring, the o-rings are removed and air flow paths are added to defeat the air spring affect.
Top-out support is provided by a coil top-out spring inside the open bath cartridge along with the bumper in the air shaft negative chamber.

Design Goals

Uneven compression from single spring systems adds friction and causes twisting of the arch and legs.
By placing a spring in each leg with very similar rates the fork can compress without twisting or leaning to one side.
Making two shorter and thinner wire springs keeps the weight of the coil system comparable to a single stiffer long heavy wire spring.
Shorter springs compress in a straighter line reducing rubbing forces and need less maintenance replacing shrink wrap and relubing.
Offering more increments is spring rates for the median weight rider allows for more precise matching of rider weights with the correct spring rate.
Hydraulic bottom out has no affect on midstroke over pressurization compared to air ramp up systems.
The hydraulic ABS and linear spring system allows for full travel on deep stroke square edged ledge and braking bumps.
Using the air spring system in conjunction with coil can create a hybrid spring system for use with heavier riders and a more progressive ramp-up if desired.

Initial Offering

Currently we are offering a limited production 2015-19 Fox 36 front fork coil conversion option available now for 160 mm travel forks and rider weights of 165-215 lbs. This is an add-on option that installs as part of our open bath cartridge and is retro fit-able for current owners of our cartridge. Dual fork springs to reduce weight and torsion when compressing. Uses standard air shaft system with minor modifications to defeat the air chamber pressure system. Current pricing is $249 installed. Total weight of system is 340 grams. Requires ABS hydraulic bottom-out system option with cartridge purchase.


The issue for coil conversion kits is the enormous amount of inventory required to suit all rider weights and fork travel differences. Currently we are only offering 3 spring rates and travel is limited to 160 mm for riders weights of 165-215 lbs. We can custom build the cartridge for 150 mm for riders weights of 160-180 lbs.

Spring rates available:

24 lb/in +24 lb/in=48 lb/in
24 lb/in +26 lb/in=50 lb/in
26 lb/in +26 lb/in=52 lb/in

Rider weight/travel
150 mm
160 mm  



Adjustable preload 3 mm increments from 5 mm to 11 mm. Oil height adjustment from 50 mm to 70 mm damper side add progression.
ABS bottom out resistance adjustment in 3mm increments to reduce or increase affect.

Requires minor modifications to stock air shaft piston and seal head to defeat air pressure system.

We are hoping to expand the options for firmer and softer spring rates as well as all travels of the Fox 36, Fox 34, Yari, Lyrik and Pike.



Anti-Bottoming System


Shown above and below is the movement of the open bath cartridge oil lock ring as it reaches the bottom of the stroke, it is also adjustable in 3 mm increments to reduce the affect if desired. This allows you to add only the amount of bottoming resistance needed. All cartridge rods have multiple grooves to select the desired oil lock ring position.


For those debating on the ABS vs FvAT/HSB here is our recommendation

The abs is not normally needed unless you want to create a very linear feel by converting to coil or modifying the air side to be more linear (because most air forks are very progressive for the last 10 mm and act like a air bump stop anyways). The FvAT/HSB is needed if you do varying types of riding such as park groomed trails or jump lines which need a firm compression feel, and backside natural rocky and rooty trails need very soft high speed compression. This will force us to compromise your set up somewhere in between the two valving options. If we valve it for the park jump lines we can then use the FvAT/HSB system to create a blow-off system to prevent the harsh feel on the high speed rocks, roots and ledge bumps and retain the firmer valving for jump lines and groomed park trails.


Add option here
Available Now

Only available as an open bath cartridge system option.


Spring Rate

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

Price $249