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Adjusting Suspension
You should now have the rear of the cycle
serviced with good bearings, proper spring, correct sag, and good oil and
nitrogen pressure in the shock. The forks should have good oil, proper
oil height, and proper springs and race sag. This article will deal
with learning how to adjust the forks and shock to achieve the base settings
for your riding style.
To start, you need a little knowledge of how
the adjusters work. When you turn the clickers you are allowing a
portion of the oil to bypass the valving mechanism. This will either
stiffen or soften the dampening depending on the direction you turn the
clickers. With most clickers, turning the screw clockwise will stiffen
the action and turning the screw counter-clockwise will soften the action.
If you have a KTM 1998-2001 with a black knob on the shock compression
adjuster it will work just the opposite: clockwise softens the action,
counter-clockwise stiffens the action.
The clickers located on the rear shock work as
follows: the clicker on the top of the shock (as installed on the
cycle) is the compression adjuster. The clicker at the base of the
shock is the rebound adjuster. On the forks, the clickers on the top
are the rebound adjusters and at the base of the fork are the compression
adjusters. But on Showa twin chamber forks (found on Suzuki 125’s from
1993 to present, Suzuki 250’s from 1993 through 2000, and Honda 250’s and
450F’s from 1997 to present), the clickers are reversed. At the
top of the fork is compression and at the base of the fork is rebound.
If a shock has only one adjuster, normally it will be rebound. If a
fork has only one adjuster, normally it will be compression.
The next points are very important when you
start to adjust the clickers. First and VERY IMPORTANT – ALWAYS START
WITH REBOUND. Rebound dampening is where your control comes from.
If rebound is too hard (slow) it will Pack (not return fully) causing the
suspension to be harsh – therefore fooling you into thinking the compression
dampening is too stiff. If the rebound is too soft (fast) it will pogo
(bouncing around) this time causing someone not experienced in suspension
tuning to think the compression dampening is the problem. The next
step is to turn the clicker clockwise until seated, then turn
counter–clockwise, counting the number of clicks. Then, using a magic
marker, write your base settings on the fork and shock for both compression
and rebound-i.e. 12C -- 10R. You can either use the factory original
settings or, if units have been worked on by suspension tuners, their
recommendations, or the middle adjustable range if you do not have a
recommended setting. The next step is to use a short practice trail –
1/2 mile long or less – with a variety of different types and sizes of
bumps. You do not want a long trail. You need a short trail that
can be ridden a lot of times so that the computer under your helmet can
average out what your suspension is doing. You can’t do this on a long
trail.
Now for the fun part: Start the cycle
and, with screwdriver on hand, head out to the practice trail. Wear
full riding gear, have race sag properly set, proper spring rates, and the
clicker positions written on the suspension units. 0Start riding your
practice trail as close to race speed as possible for about 10 minutes so
that you can get a good feel for how the suspension is working with these
base settings. Now you are going to screw up the suspension on purpose
to get a feel for how it reacts when one of the adjusters is improperly
adjusted. This is called CONTROLLED SCREW-UP. Start with the
rebound adjuster on the suspension unit that felt the worst to you
(remember, you ALWAYS start with rebound), turning it clockwise 6 clicks
(harder or slower). Now the unit will tend to pack. Remember, if
you are adjusting forks, you normally have a rebound adjuster on each fork –
be sure to turn both an equal amount. Now start riding, slower at
first, and as you get a feel for how the improperly adjusted unit is
reacting, try picking up the pace to get the feel of a packing suspension
unit. After about 10 minutes, stop riding and make a mental note of
how the unit worked compared to how it worked at your base setting.
Now turn the rebound clicker back to it’s base setting (6 clicks
counter-clockwise) and then turn it another 6 clicks counter clockwise so
that the suspension unit will be softer or faster and will tend to pogo.
Again start riding slowly and build speed as you feel comfortable.
After about 10 minutes, stop riding and judge how the suspension unit felt
in the 3 different settings. Now turn the rebound clicker 2 clicks clockwise
and start riding. Hopefully this will feel a little better than your
last ride. After a period of time, stop and adjust another 2 clicks
clockwise and ride. Keep doing this, 2 clicks at a time, until the
quality of ride begins to get worse. Then, turn the rebound clicker 1
click counter clockwise and ride, continuing to adjust 1 click at a time
until you find your NEW base setting. You now have the rebound on the
suspension unit (i.e. fork or shock) that you started with adjusted for the
best setting for you. Write this setting down on the suspension unit.
Now do the same procedure with the compression
adjuster or adjusters: six clicks stiffer than base, 6 clicks softer
than base, then 2 clicks at a time toward stiffer until it gets too stiff,
then 1 click toward softer until you reach the ideal setting. Do the
same for the other end of the cycle. Now you have both ends adjusted
for your practice trail and you have experienced poorly adjusted suspension
units. When you ride or race somewhere else the computer under your
helmet will be able to help you get things tuned in very quickly.
Remember – write down these NEW base settings on the suspension units and in
a race log. This will help you get things set up right when you
go back to a previously ridden course.
A FEW TIPS. From the base settings that
you have tuned for yourself: For Sand runs, adjust to stiffen
compression and slow rebound. For Rocks, Roots, and Potholes, adjust
to soften compression, slow rebound. For Mud, adjust to stiffen
compression, speed up rebound. If your shock has a high speed
compression adjuster, it does not have clicks. Therefore, you will need to
adjust by PARTS OF A TURN from full stiff (clockwise) turning out – i.e.:
1 turn, 1 5/8 turns, etc. Work on tuning this adjuster just as
you would the screw clickers. Remember: Always start with
rebound adjustment and, if in doubt as to which adjuster is off, always do
rebound. The rebound adjustment is the most important but the hardest
to determine if it is right or wrong. By doing rebound first you will
not get fooled into thinking the problem is compression. |
