Tuning your suspension - Where to start?
Posted 30 January 2012 - 04:49 PM
Posted 22 March 2012 - 09:38 PM
Posted 28 August 2012 - 02:33 AM
Posted 12 September 2012 - 05:28 AM
TOO TECH RACING
SET-UP INSTRUCTIONS (For Non Twin Chamber Showa & KYB)
STEP 1: Measure suspension "Race Sag". (Most important adjustment there is)
First: Put the bike on a center stand and release the accumulated air from the front forks.
Second: Put an ink mark on your fender and measure the distance between the Rear Axle and the Mark on your fender.
Third: Take the bike off the stand and position it on level ground, stand on the foot pegs and support yourself against
some wall; then measure the distance between the Rear Axle and the ink Mark on your fender.
Forth: The difference between these two measurements should be adjusted to________ inches.
- To change your Race Sag, turn the large adjusting nuts on your shock using a long screwdriver and big hammer.
STEP 1a: Balance Turning with Stability by fine-tuning the Rear Race Sag.
- If the rear end squats too much under acceleration, and / or the bike doesn't want to turn sharp enough; tighten your rear
spring preload by adjusting your rear sag to ______ inches. (Remember- Raising the rear end helps turning)
- If the front end rides low, turns too sharp, and/or tends to Head Shake at high speed; loosen your rear preload by adjusting
your rear sag to _______inches. (Remember - Lowering the rear end helps stability and reduces head shake)
STEP 2: Adjust compression damping front & rear.
- If "bottoming" is noted, the compression adjusting screw should be turned "in" (clockwise) to stiffen the compression stroke.
The front fork compression adjuster is the Slotted Screw at the bottom of the fork.
The rear shock compression adjuster is the Slotted Screw and the Hex Nut (if available) at the top of the shock in the
reservoir. First turn the hex nut 1/8-1/2 of a turn “in”, then fine-tune the low speed damping using the slotted screw.
- If no bottoming is noted, but one end is stiffer than the other; turn the adjuster “out" (counter clockwise) at the stiff end. This
will soften the stiff end making it more compatible with the other “softer” end.
STEP 3: Adjust Rebound damping front/rear. (Critical adjustment, change 1or 2 clicks at a time)
- If either the front or rear tends to kick up (rebound) faster than the other after landing from a large jump, the rebounds are
not balanced front to rear. Slow down the end that kicks up by adjusting the rebound screw "in" (clockwise) 1 click at a time
The front fork rebound adjuster is the Slotted Screw at the top of the forks.
The rear shock rebound adjuster is the Slotted Screw at the bottom of the shock.
- If the front end bounces up after landing from a jump, turn the rebound adjuster on the forks "in" to slow the front return.
- If the rear end kicks side to side on straights or kicks up after landings, turn the shock reb. Adj. ‘in’ to slow the rear return.
(Remember; too slow a rebound setting causes "packing" because the suspension does not have time to return to its
original ride height in-between bumps. This causes the bike to feel stiff and kick side to side.)
Adjustment Notes: Bring a small screwdriver with you when testing and make your adjustments right at your test track.
Make all damping decisions with the suspension hot. Test your adjustments immediately back on the same test track.
Rule Of Thumb: On hard pack and fast tracks; run your rebound at both ends "one click faster” to follow the terrain.
On deep sand tracks, run your rebound “slower at the rear, to prevent bouncing up and out of the rollers.
DON’TS – Don’t make damping changes in the garage - this can lead to nasty surprises.
-- Don’t let your friends adjust your suspension – get involved yourself. Call me if confused!
Compression: (Hex Nut on Reservoir (Hi Speed)) _______ turns "out" from full hard. Shock Spring Rate _____
Compression: (Screwdriver Slot on Reservoir) ______ clicks "out" from full hard.
Rebound: (Screwdriver Slot at bottom of shock) ______ clicks "out" from full hard. Adjust between ____ and ____ clicks.
Oil: Torco RSF Lite. Nitrogen pressure 155 psi.
Compression (Screwdriver Slot at bottom) _____ clicks "out" from full hard. Fork Spring Rate _____ Preload _____
Rebound (Screwdriver Slot at top) ______ clicks "out" from full hard. Adjust between _____ and _____ clicks.
Oil: Maxima or Spectro _________ cartridge oil. Oil Height adjusted to ______ inches from the top.
NOTES: After “Suspension Break-in”, the compression will become softer and the rebound will become faster.
(This may require the adjusters to be turned in slightly after “Suspension Break-in”)
- At least once a day put your bike on the stand and release the accumulated air from your front forks. (I have speed
- Check your Race Sag at least once a month to adjust for spring settling and chain adjustments.
- Change suspension fluid every 6 months to maintain maximum suspension performance.
- Do not use Impact Wrenches to disassemble your suspension – this can cause loosening of your internal valving stacks.
Call Rick Johnson @ (310) 371-3887 to discuss your suspension's performance.
Visit our WEB SITE at www.tootechracing.com
STEP 1 - BALANCE REAR SPRING PRELOAD WITH FRONT FORK HEIGHT
ADJUST RACE SAG - The most important adjustment
Typical Starting Measurement: 3 7/8" Short track and Super cross
4" Natural terrain motocross
4 1/8" Gran Prix & Desert
Adjust the forks to the standard height in the triple clamps before starting any adjustments. (Usually ≈ 3/16” above clamp)
- Increasing the preload on your rear spring will decrease the Race sag. This will raise the rear of your bike placing more
weight on the front wheel and reduce the caster angle. This will always make the bike turn sharper; but if you tighten the
spring too far, it will make the bike twitchy and promote head shake.
- Decreasing the preload on your rear spring will increase the Race sag. This will lower the rear of your bike putting less
weight on the front wheel and cause it to ride like a "Chopper". This will reduce head shake, make the bike go straighter, and
be more secure in high-speed sections; but if you loosen the spring too far the bike will be harder to turn.
- To fine tune the spring preload (Race Sag), try tightening the rear spring adjusting nut (1) turn at a time and mentally note
how much easier the front end will dive into a turn and hold the inside line. Continue this spring tightening until the bike
becomes twitchy and unstable or it feels like you're always pulling up on the handlebars. Measure and record your Race
- Then try loosening the rear preload (1) turn at a time and mentally note how the rear end "Squats" down and traction
increases as you exit each turn. When you reach the point of excessive front-end lift (wheelies) and loss of steering, or you
begin to have trouble holding a tight turn, the spring is too loose and you have too much Race Sag. Measure and compare
these two extremes and then reach a compromise between them that balances 'stability' and 'tight turning'.
ADJUST the front end ride height to match the rear end:
- If the Race Sag compromise you determined above is close to the typical measurements listed above, your fork height
adjustment in the triple clamps is probably about right.
- Raising the forks in the triple clamps will lower the front end making the bike turn sharper but will reduce high-speed
stability. (Similar to increasing the rear preload)
- Lowering the forks in the triple clamps will raise the front end making the bike harder to turn but will increase high-speed
stability. (Similar to lowering the rear preload)
Note: Once you have established the best overall ride height front and rear; record these settings as your baseline. For
added stability on a Desert or Gran Prix track, I will push my forks down about 1/8". For Motocross I will pull them back up to
improve turning. To further improve turning on a flat Supercross style track, tighten the rear spring about 1 turn.
The goal is balance front to rear. The front should dive into a turn about the same as the rear squats out of a turn.
STEP 2 - ADJUST COMPRESSION DAMPING FOR BOTTOMING –
Increasing your compression damping (the Screw & Hex on the shock reservoir), will slow down the compression stroke and
decrease rear end bottoming. Use the Hi Speed Hex Adjuster to make major changes to the Shock compression damping,
then fine tune with the slotted adjuster. Turn your compression adjuster "in" (clockwise) to reduce bottoming. If you never
bottom, try turning your adjuster "out" (counterclockwise) to soften the compression damping and use more travel. Slight
occasional bottoming is OK but don't allow the bike to crash down when bottoming.
HI/LO Speed Adjuster – Try stiffening the Hi and softening the Lo to make the bike use more travel in hard pack.
Try softening the Hi and stiffening the Lo to make the bike bide higher in the soft sand.
Increasing the compression damping (the screw at the bottom of the forks), will slow the compression stroke, which will hold
the front end up higher and decrease front end bottoming. Turn your compression adjuster "in" (clockwise) to reduce
bottoming. If you never bottom, try turning the adjuster "out" to soften the compression damping.
Note: -Softer, “adjuster screw out", compression settings provide a plush, mushy feel which works well for cross country
racers trying to go straight and conserve energy.
-Stiffer, “adjuster screw in", compression settings hold the suspension up and out of holes and provide more lift on
jump take-offs. Additionally, body english and throttle changes transfer directly into the dirt instead of getting lost in a mushy
STEP 3 -ADJUST REBOUND DAMPING for STABILITY and JUMPING
- This adjustment is extremely important and must be fine-tuned by the rider very carefully. This adjustment determines how
much time it takes the wheel to return to its original position after compressing into a bump. In steps 1 & 2 you determined
how much compression travel would be used as you hit each bump. The rebound damping must now be "tuned" to return the
suspension to its original ride height before contacting the next bump. Faster riders will have less time between bumps
causing them to need a slightly faster rebound.
- If the rebound is too fast, the bike will bounce up after landing from a large jump or kick sideways through rough sections. If
the rebound is too slow, the wheel will not have enough time to return between bumps, causing it to "pack down" becoming
harsh on the next bump. Rebound "Packing" can occur on the second bump and can be confused with too much
- Experimentation is required to fine-tune this adjustment. Stick a small screwdriver in your boot and concentrate on the
highest speed and most aggressive portions of your test track.
- Start by speeding up the front rebound by turning the screw at the top of your forks "out" (counterclockwise) 2 clicks then
ride your test track. Continue turning the adjuster out until the bike kicks up after landings or bounces up for no good reason.
Record this setting for reference.
- Then try turning the rebound "in" (clockwise) 2 clicks at a time until the front end begins to get stiff or your arms begin to get
tired quickly (arm pump). These are signs of packing. These two extremes define your rebound working range.
- I prefer to run my rebound as fast as possible. I would rather have the front end kick up occasionally than pack down.
Note: - "Slightly fast fork rebound will reduce headshake and arm pump." –
- “Slightly slow fork rebound will help the front end stick in a berm.” --
- Start by speeding up the rear rebound by turning the screw at the bottom of your shock "out" (counterclockwise) 2 clicks
then ride your test track. Continue turning the adjuster out until the bike kicks up after landings or kicks side to side. Record
this setting for reference.
- Then try tuning the rebound "in" (clockwise) 2 clicks at a time until the rear end begins to pound and get stiff. It may also
feel like you have a flat tire, the rear is riding low, or like the rear is "dead". You will probably get tired faster. These are signs
of packing. These settings define your rebound working range.
- I prefer to run my rebound as fast as possible, but always prefer the front to be faster than the rear..
Note: -- "Slightly faster rebound settings will help you clear double jumps and ride aggressively."
-- "Slightly slower rebound settings conserve energy in deep sand and desert whoops."
STEP 4 -BALANCING FRONT AND REAR
Regardless of personal preference on compression stiffness and rebound speed, both ends must be balanced and work
- The front spring and compression setting must coordinate with the rear spring and compression setting.
- If the front forks are too soft and plow through a whoop but the rear end rides up and over it, the bike will go into the "endo"
position. To cure this you would try to stiffen the front compression to make the front ride higher over the bump to match the
rear end. First try a combination of turning the fork compression adjuster screw in, adding 1/4" fork oil, adding preload to the
front fork springs, and pushing the fork tubes down in the triple clamps. Also try speeding up the front rebound, clicker "out" 1
or 2 clicks. All the above changes combine to make the front end ride higher which minimizes the dreaded “endo”.
- When you reach the limit on making the front stiffer, try adjusting the rear end softer. A softer rear will reduce the load to the
front end causing the front to bottom less. Try a combination of turning the shock compression setting "out", and reducing
rear spring preload. Also try slowing the shock rebound, adjust the clicker "in" 1 click, to make the rear stay down after the
- Reverse the logic listed above if the fork is stiffer than the rear.
The front and rear rebound settings must coordinate to throw the bike up level on jump take-offs. (First the compression
balance adjustments above must be made.) If the front end continuously jumps higher than the rear, try a combination of
slowing the fork rebound, clicker "in" 1 click, and speeding the rear rebound, clicker "out" 1 click. This will cause the front to
ride lower and the rear to ride higher.
General Note: Heavier Riders, Very Aggressive Riders, and Desert Riders will usually prefer heavier spring rates
Posted 07 June 2013 - 10:23 PM
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