Spring Conversion Kit

Change your forks from air pressure to coil spring with our Spring Conversion Kit.

No more checking fork psi before each ride. No more losing all air pressure with a blown seal.

Precision Concepts air fork to spring conversion kit

Convert From Air To Spring For More Consistency

For riders wishing to change their WP AER (or Showa TAC/SFF) air forks to traditional coil spring, we offer a Spring Conversion Kit Service. The kits we use are high quality and offer different options depending on your needs and preferences.

WP 6500 Dual Spring Conversion Kit

The 6500 dual spring conversion kit is our most popular kit for the WP AER forks, which replaces the internals with dual springs and WP parts for smooth installation and consistent action.

Starting at $1,299.00

Kayaba Dual Spring Conversion Kit

The Kayaba dual spring conversion kit replaces the internals and axle clamps with KYB parts for the performance and tolerance that Kayaba offers.

Starting at $1,795.00

K-Tech Single Side Function Spring Conversion Kit

The K-Tech kits offers an affordable option to convert an air fork to spring. It replaces the air chamber fork internals with a coil spring, which offers good performance as a single-side-function fork.

Starting at $699.00

Benefits of Our Spring Conversion Kit

Consistent Action While Riding
Even when everything is working perfectly, the air fork will build pressure due to ambient temperature, altitude, and heat. This phenomena can't be controlled and leads to a stiffer and often harsher feel while riding. Switching to a coil spring offers the more consistent handling character of a conventional spring fork.
No Catastrophic Failure if Seal Blows
If something internal in the air fork were to fail, such as a fork seal, the air fork can lose pressure to the point that the fork loses travel. At the motocross track, this can make for an early end to your day. Alternatively, a failure on a trail ride could leave you stranded miles from camp. Switching to a coil spring eliminates this risk as the fork is held up by the spring instead of air pressure.
Reduced Stiction Feel
A result of sealing the fork chamber(s) to maintain the air pressure required in an air fork is a noticeable increase in stiction. Switching to a coil spring reduces this stiction to more common, conventional levels, which improves small bump absorption and handling feel over chatter.

Additional Info

How To Get Started

Once you give us a call—(951) 697-8488—we'll get your Spring Fork Conversion Service scheduled and give you and estimated completion date. If you're dropping off your suspension, we'll collect any further information we need form you at that time. We also offer a suspension removal and remounting service, if you'd like to bring in your bike. If you're shipping your suspension and we need any additional information, we'll give you a call.

CLICK HERE to view our Shipping Info page.

After gathering your information, we'll then make a determination of the spring rate you need based upon numerous factors, including your weight, skill, riding style and preferred terrain/discipline.

If you're having us install the Spring Conversion Kit in conjunction with our Suspension Revalve Service (highly recommended!), we'll additionally gather the info we need to customize your valving and create a unique spec for you.

Learn more about our Revavle Service by CLICKING HERE.

Air Fork Drawback #1: Forks Build Pressure While Riding

Even when everything is working perfectly, the air fork will build pressure due to ambient temperature, altitude, and heat. This phenomena can't be controlled. Using nitrogen in the fork instead of air may cut down the build up of pressure by a percentage. However, in our testing, even nitrogen does gain some pressure.

As a result, the action of the air fork actually changes. We've seen air pressure changes during testing as high as six pounds, which is equivalent to three steps stiffer on a standard spring rate. Of course, continually bleeding the outer chamber is an option. But to adjust the inner chamber pressure requires a pump. Additionally, it demands continuous bleeding between motos at a track, or carrying a pump while on a longer trail ride in order to maintain consistent performance.

Air Fork Drawback #2: There is a Risk of Catastrophic Failure

A fact became very apparent on the highest stage of motocross in 2016, when Ken Roczen's forks dropped lower and lower throughout the first moto at Glen Helen. That fact was that the air fork carries with it the risk of failure and resulting loss of pressure.

If something were to fail, such as a fork seal, the air fork can lose pressure to the point that the fork loses travel. At the motocross track, this can make for an early end to your day. Moreover, a failure on a trail ride could leave you stranded miles from camp.

Air Fork Drawback#3: Stiction is Noticeably Increased

A result of sealing the fork chamber(s) to maintain the air pressure required is a noticeable increase in stiction. If you want to feel the difference in stiction between a spring fork and an air fork, just go to your local dealership. Push down on the front end of a RMZ or KX from the mid-to-late 2010's that comes with a TAC fork. Then, push on a newer Japanese model that has spring forks and feel the comparison. There will be a huge difference in stiction. Now, the air forks do work better when you're riding than they feel on the showroom. Nevertheless, that stiction is still there and has an impact on the performance of the forks.

Is There A Benefit To Air?

Any of the traits listed above might be worth the trade-off if the performance of the air fork was worth it. However, through testing we've found the biggest benefit to the air fork is the weight savings. And while the weight difference is a benefit, it doesn't outweigh the performance difference. In all of our testing, we've always been able to get better overall performance out of the spring fork.