AIR PRESSURE FILL PROCEDURE
1. Unthread and remove the negative air chamber cap found on the
bottom of the spring leg.
2. Attach a high-pressure, suspension specific pump to the valve and
using the pump’s bleed button, remove all pressure. Remove the pump.
3. Locate the positive air chamber cap at the top of the spring leg.
Unthread and remove the positive air chamber cap and attach a high-
pressure suspension specific pump to the valve.
4. Fill the positive air chamber to the desired pressure. Remove the
pump and re-install the positive air chamber cap.
5. Return to the negative air chamber; attach the pump, fill to the
desired pressure, remove the pump, and re-install the negative air
chamber cap.
AIR SPRING SETUP
The Raven uses MRP’s FulFill™ air spring system with independent
positive and negative chambers. It is critical the you follow the steps
below in order for proper suspension function.
Because the Raven is a high-performance fork and its desired
feel is highly subjective, we recommend experimenting with different
air pressure settings in conjunction with air-volume modifications (using
the included Huck Pucks).
In testing, we’ve found that the common usable range for air
pressure is between 48 - 150 PSI. A good starting point for most riders
on our 150 and 160mm forks seems to be a positive pressure (in PSI)
equal to approximately 40-45% of body weight in pounds (lbs.). For
example, a 175 lb. rider should start with 70 PSI in the positive chamber.
Shorter travel forks may require more pressure than this, and longer
(170mm) forks less, but this a good baseline. Most riders like slightly
more pressure in the negative chamber. You may inflate the negative
chamber to as much as 10% or 10 PSI (whichever is greater) more than
the positive chamber.
HUCK PUCK (AIR VOLUME) TUNING
Some Raven models come stock with Huck Pucks installed. The
maximum number of huck pucks your fork can accomodate depends
on chassis (wheelsize) and travel. The installation of Huck Pucks
reduces the volume of the positive air spring and thereby changes the
overall spring curve. With additional Huck Pucks, the biggest change
occurs at the end of the stroke, where it becomes more progressive
(less susceptible to bottom-out).
HUCK PUCK INSTALLATION OR REMOVAL
1. Release all air pressure from the negative air spring by depressing
the Schrader valve core on bottom of the air leg of the fork. Repeat
the same for the positive spring (at the top of the air leg of the fork). To
ensure all air is released from both chambers, cycle the fork 2-3 times
and depress the positive valve core again.
3. Unthread the spring-side top cap from the crown of the fork using a
cassette tool.
4. With the top cap removed, install or remove Huck Pucks. Use up to
a 4mm hex key or something of similar diameter inserted into the side
of the pucks to tighten or loosen the pucks. Tighten any installed pucks
onto the bottom of the top cap snugly so they do not come loose over
time.
5. Re-install the top cap by threading it back into the fork crown and
tighten to 12 Nm.
6. Inflate the air spring as outlined in the previous section. Added Huck
Pucks will require slightly lower air pressure values to preserve the
previous sag level.
27.5” MODELS
170 and 160: 0 installed, 5 max.
150: 0 installed, 6 max.
140: 1 installed, 7 max
27.5+ / 29” MODELS
160: 0 installed, 5 max.
150: 0 installed, 6 max.
140: 1 installed, 7 max.
130: 2 installed, 8 max.
120: 3 installed, 8 max.
If you are unfamilar with lbs. (pounds) the conversion from kg.
(kilograms) is:
kg. x 2.2 = lbs.
Here, below, are some examples of baseline settings, including
rebound settings (counted as “clicks from closed”):