1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Suspension Guide?

Discussion in 'Tech' started by craigcoble2000, Sep 29, 2008.

  1. craigcoble2000

    craigcoble2000 Well-Known Member

    I had supsension guide and lost......:mad:

    In the info it stated things like: Forks, Too Much Compression can cause....and then it would give its suggestions for a solution.

    Anyone have this link??? If so can you send it to me.....:bow:
     
  2. kan3

    kan3 Well-Known Member

    Suspension 101.

    Static sag without rider
    Hold the bike upright on a flat surface. Independently lift front and rear until the suspension is fully extended, the value should be approximately:

    Type Front sag Rear sag
    Super Bike 20-30 mm 5-10 mm
    Super Sport 20-30 mm 5-10 mm
    RR 250 15-25 mm 0-5 mm
    RR125 15-25 mm Just top out 0 mm

    Static sag with rider
    The accepted manner to adjust the spring ratio is to measure how much stroke is used with the rider sitting on the bike in straight line position (behind fairing) after you have set the correct static sag without rider. Normally 1/3 of the full stroke is a good starting point for all machines. This is only a guide line for the right spring ratio. The final check must be done on the circuit.

    Rebound damping:
    *Rear suspension
    Too much rebound damping can cause:
    - The rear "jumps" on the bumps instead of following the surface.
    - The rear "jitters" under braking.
    - It holds the rear down with the result that the bike will understeer!
    - It can cause overheating in the hydraulic system of the shock absorber and make it fade, in other words, it will loose damping when hot.

    Too little rebound damping can cause:
    - The rear "tops out" too fast under braking, causing the rear wheel to jump
    - The bike feels unstable.

    *Front suspension
    Too much rebound damping can cause:
    - Oversteering!
    - It will give poor grip of the front tire.
    - It feels like the front wheels will tuck under in corners.

    Too little rebound damping can cause:
    - Understeer!
    - The front can feel unstable.

    Compression damping
    Rear suspension
    Too much compression damping can cause:
    - The rear wheel to slide under acceleration .
    -It can give a harsh ride over bumps.

    Too little compression damping can cause:

    - The rear wheel start to bump sideways under acceleration out of the corner. - The bike will squad too much (rear is too low), that will cause the front to loose grip.

    Front suspension

    Too much compression damping can cause:
    - Good result during braking.
    - Feels harsh over the bumps.

    Too little compression damping can cause:
    - Strong diving of the front.

    Adjustment advice:
    Compression damping should be adjusted together with front fork oil level.

    Spring ratio:
    Rear
    Too hard spring ratio:
    - Gives easy turning into corners.
    - Makes the rear feel harsh.
    - Create poor rear wheel traction.

    Too soft spring ratio:
    - Gives good traction in acceleration.
    - Creates understeer in entry of corner.
    - Makes too much suspension travel which will make it difficult to "flick" the bike from one side to the other in a chicane.
    - Will give a light feeling in the front.

    Front
    Too hard spring ratio:
    - Good under braking.
    - Creates understeer.
    - It feels harsh in the corners.

    Too soft spring ratio:
    - Gives easy turning into corners.
    - Creates oversteer.
    - Can cause front to tuck under.
    - Bad under braking (diving).

    Front fork oil level
    First see manual. The modern front fork of cartridge type is very sensitive for oil Level changes, because of the small air volume Air inside the front fork works as a spring. The different level of oil affects the spring ratio from the middle of the stroke and has a very strong effect at the end of the stroke.
    When the oil level is raised:
    The air spring in the later half stage of travel is stronger, and thus the front forks harder.

    When the oil level is lowered:
    The air spring in the later half stage of travel is lessened, and thus the front forks are softer. The oil level works most effectively at the end of the fork travel.

    Note: Adjust the oil level according to your manual.




    BASIC SETUP - Check the following first:

    Forks/Rear Shock - Race sag 25-30 mm, 1 - 1 3/16 inch
    Forks/Rear Shock - Street sag 30-35 mm, 1 3/16 - 1 3/8 inch
    Check chain alignment. If not correct, sprocket wear is increased.
    Proper tire balance and pressure. If out of balance, there will be vibration in either wheel
    Steering head bearings and torque specifications, If too loose, head will shake at high speeds.
    Front end alignment. Check wheel alignment with triple clamps. If out of alignment, fork geometry will be incorrect and steering will suffer.
    Crash damage, check for proper frame geometry.

    --------------------------------------------------------------------------------

    TROUBLESHOOTING FORK DAMPING PROBLEMS

    Fork Adjustment Locations:

    Rebound adjustment (if applicable) is located near the top of the fork.
    Compression adjustment (if applicable) is located near the bottom of the fork.
    Spring preload adjustment (if applicable) is generally hex style and located at the top of the fork.
    Forks - Lack of Rebound:

    Symptoms

    Forks are plush, but increasing speed causes loss of control and traction.
    The motorcycle wallows exiting the turn causing fading traction and loss of control.
    When taking a corner a speed, you experience front-end chatter, loss of traction and control.
    Aggressive input at speed lessons control and chassis attitude suffers.
    Front end fails to recover after aggressive input over bumpy surfaces.
    Solution

    Insufficient rebound - Increase rebound "gradually" until control and traction are optimized and chatter is gone.

    Forks - Too Much Rebound:


    Symptoms

    Front end feels locked up resulting in harsh ride.
    Suspension packs in and fails to return, giving a harsh ride.
    Typically after the first bump, the bike will skip over subsequent bumps.
    With acceleration, the front end will tank slap or shake violently due to lack of front wheel tire contact.
    Solution

    Too much rebound - Decrease rebound "gradually" until control and traction are optimized.

    Forks - Lack of Compression:

    Symptoms

    Front-end dives severely, sometimes bottoming out over heavy bumps or during aggressive breaking
    Front feels soft or vague similar to lack of rebound.
    When bottoming, a clunk is heard. This is due to reaching the bottom of fork travel.
    Solution

    Insufficient compression - Increase "gradually" until control and traction are optimized.

    Forks - Too Much Compression:

    Symptoms

    Front end rides high through the corners, causing the bike to steer wide. It should ride in the middle of suspension travel.
    Front wheel bounces over bumps while ripples and bumps are felt directly in the triple clamps and through the chassis.
    Ride is generally hard, and gets even harder when braking or entering turns.
    Solution

    Too much compression - Decrease compression "gradually" until the bike neither bottoms or rides high, and control and traction are optimized.

    Symptom

    Front end chatters or shakes entering turns. This is due to incorrect oil height and/or too much low speed compression damping
    Solution
    First, verify that oil height is correct. If correct, then decrease compression "gradually" until chattering and shaking ceases.


    --------------------------------------------------------------------------------

    TROUBLESHOOTING SHOCK DAMPING PROBLEMS

    Shock Adjustment Locations:

    Rebound adjustment (if applicable) is located at the bottom of the shock.
    Compression adjustment (if applicable) is located at the top of the shock or on the reservoir.
    Spring preload is located at the top of the shock.
    Shock - Lack of Rebound:

    Symptoms

    The ride will feel soft or vague and as speed increases, the rear end will want to wallow and/or weave over bumpy surfaces and traction suffers.
    Loss of traction will cause rear end to pogo or chatter due to shock returning too fast on exiting a corner.
    Solution

    Insufficient rebound - Increase rebound until wallowing and weaving disappears and control and traction are optimized.

    Shock - Too Much Rebound:

    Symptoms

    Ride is harsh, suspension control is limited and traction is lost.
    Rear end will pack down, forcing the bike wide in corners, due to rear squat. It will slow steering because front end is riding high.
    When rear end packs in, tires generally will overheat and will skip over bumps.
    When chopping throttle, rear end will tend to skip or hop on entries.
    Solution

    Too much rebound - Decrease rebound "gradually" until harsh ride is gone and traction is regained. Decrease rebound to keep rear end from packing.

    Shock - Lack of Compression:

    Symptoms
    The bike will not turn in entering a turn.
    With bottoming, control and traction are lost.
    With excessive rear end squat, when accelerating out of corners, the bike will tend to steer wide.
    Solution

    Insufficient compression - Increase compression "gradually until traction and control is optimized and/or excessive rear end squat is gone.

    Shock - Too Much Compression:

    Symptoms

    Ride is harsh, but not as bad as too much rebound. As speed increases, so does harshness.
    There is very little rear end squat. This will cause loss of traction/sliding. Tire will overheat.
    Rear end will want to kick when going over medium to large bumps.
    Solution

    Too much compression - Decrease compression until harshness is gone. Decrease compression until sliding stops and traction is regained.
     
    Last edited: Sep 29, 2008
    jd41 likes this.
  3. kan3

    kan3 Well-Known Member

    Front Fork Problems
    Possible Cure

    Race sag too small -
    Reduce preload.

    Race sag too great -
    Increase preload.

    Forks compress too far on smooth turns -
    Stiffer springs, increase preload.

    Forks dive too far (bottom out) -
    Stiffer springs, reduce air gap, possibly increase preload.

    Always losing front end on corner entry -
    Softer springs, adjust weight distribution.

    Front end chatters coming out of corners - Softer rebound springs or main springs, reduce damping.

    Bike difficult to turn in -
    Softer springs, reduce preload or compression damping, alter steering geometry

    Front wheel skips on bumps -
    Softer springs, reduce compression damping, increase air gap.

    Forks judder when braking on a straight -
    Reduce compression damping.

    Forks dive too fast -
    Increase compression damping.

    Forks pump down on fast bumpy corners -
    Reduce rebound damping.

    Excessive pogo action through chicanes -
    Slightly increase rebound damping.

    Front end shakes (not chatters) in corners -
    Increase rebound damping.

    Front end shoots up too fast after braking -
    Increase rebound damping.


    --------------------------------------------------------------------------------

    Rear Shock Problems
    Possible Cure

    Race sag too great -
    Increase preload.

    Race sag too small -
    Reduce preload.

    Rear squats on acceleration -
    Stiffer spring, increase anti-squat angle, slightly increase compression damping.

    Very Harsh ride over ripples -
    Reduce compression damping.

    Bike wallows - Increase rebound damping.

    Rear jacks up too fast on braking -
    Increase rebound damping.

    Rear end chatters exiting slow corners -
    Increase rebound damping.

    Bike kicks off ripples or bounces on bumps -
    Increase rebound damping.

    Rear end pumps down on bumpy corners -
    Reduce rebound damping.




    LACK OF COMPRESSION DAMPING ( Front Fork )

    Front end dive while on the brakes becomes excessive.
    Rear end of motorcycle wants to "come around" when using front brakes aggressively.
    Front suspension "bottoms out" with a solid hit under heavy braking and after hitting bumps.
    Front end has a mushy and semi-vague feeling, similar to lack of rebound damping.


    TOO MUCH COMPRESSION DAMPING ( Front Fork )

    Overly harsh ride, especially right at the point when bumps and ripples are contacted by the front wheel.
    Bumps and ripples are felt directly - the initial hit is routed through the chassis instantly, with big bumps bouncing the tire off the pavement.
    The bike's ride height is affected negatively - the front end winds up riding too high in the corners.
    Brake dive is reduced drastically, though the chassis is upset significantly by bumps encountered during braking.


    LACK OF REBOUND DAMPING ( Front Fork )

    The fork offers a supremely plush ride, especially when riding straight up. However, when the pace picks up the feeling of control is lost. The fork feels mushy, and traction "feel" is poor.
    After hitting bumps at speed, the front tire tends to chatter or bounce.
    When flicking the bike into a corner at speed, the bike will tend to "porpoise" or wallow a bit, before settling down. Getting aggressive with the controls makes it worse. As speed increases and steering inputs become more aggressive, chassis attitude and pitch become a real problem, with the front traction feedback going numb after the bike is countersteered hard into a turn.


    TOO MUCH REBOUND DAMPING ( Front Fork )

    The ride is quite harsh - just the opposite of the plush feet of too little rebound. Rough pavement makes the forks feel as if they're locking up with stiction and harshness.
    Under hard acceleration exiting bumpy corners, the front end feels like it wants to "wiggle" or "tankslap." The tire feels as if it isn't staying in contact with the pavement when on the gas.
    The harsh, unforgiving ride makes the bike hard to control when riding through dips and rolling bumps at speed. The suspension's reluctance to maintain tire traction through these sections erodes rider confidence.



    --------------------------------------------------------------------------------

    LACK OF COMPRESSION DAMPING ( Rear Shock )

    Too much rear end "squat" under acceleration - bike wants to steer wide exiting corners (since chassis is riding rear-low/nose-high).
    Hitting bumps at speed causes the rear to bottom, which upsets the chassis.
    Chassis attitude affected too much by large dips and "G-outs" - steering and control become difficult due to excessive suspension movement.


    TOO MUCH COMPRESSION DAMPING ( Rear Shock )


    Ride is harsh, though not quite as bad as too much rebound - however, the faster you go the worse it gets.
    Harshness hurts rear tire traction over bumps, especially during deceleration.
    There is very little rear end "squat" under acceleration.
    Medium to large bumps are felt directly through the chassis - when hit at speed, the rear end kicks up.


    LACK OF REBOUND DAMPING ( Rear Shock )

    The ride is plush at cruising speeds, but as the pace increases, the chassis begins to wallow and weave through bumpy corners.
    Poor traction over bumps under hard acceleration - rear tire starts to chatter due to lack of wheel control.
    Excessive chassis pitch through large bumps and dips at speed - rear end rebounds too fast, upsetting chassis with a pogo-stick action.

    TOO MUCH REBOUND DAMPING ( Rear Shock )

    Very harsh ride - rear suspension compliance is poor and "feel" is vague.
    Poor traction over bumps during hard acceleration (due to lack of suspension compliance).
    Bike wants to run wide in corners since the rear end is "packing down" - this forces a nose-high chassis attitude, which slows down steering.
    Rear end wants to hop and skip when the throttle is chopped during aggressive corner entries




    Part 2.

    Suspension 101: Round 2, by Max McAllister (Traxxion Dynamics)


    Do not be embarrassed if you are unfamiliar with the basics. Most racers aren't. This is one reason some riders struggle as novices for years and never improve. Some racers crash frequently and don't understand why. If your bike isn't set up properly, it will frighten you and you will assume that you are going as fast as you can safely. In the meantime, some of your peers just continue to go faster while you stagnate. You can change this. Sometimes it's as easy as turning a couple of screws. Then you can be frightened because you're really haulin' ass!!!!!!!

    TERMINOLOGY:

    Sag....Distance a motorcycle compresses with weight on it. There are two types of sag we deal with. The first is "free" (static) sag, which is the amount the springs compress under the weight of the bike. The second is rider sag, which is the amount the springs compress with the rider on board.

    Preload....This is the amount a spring is compressed with no weight on it at all

    Dampening....this is the primary function of your suspension. It controls the movement of your springs as they encounter irregularities in the pavement. Without dampening, you are riding a pogo stick. There are two types we will address. The first is compression dampening, which controls the downward movement of your motorcycle (upward movement of the wheel). The second is rebound dampening. It controls the upward movement of your motorcycle (extension of the suspension).

    Rake....Angle of your steering axis.

    Trail....Distance the contact patch of the front tire trails the steering axis' imaginary point of contact with the ground. More trail makes your bike more stable. Less trail makes it steer faster. Watch the wheels of a grocery cart, they always fall in line behind the cart when you push it forward. This self-aligning effect is the result of trail.
    Ride Height....distance the motorcycle rides above the ground. Can be changed at the front or the rear (or both) to alter handling characteristics.
     
    Last edited: Sep 29, 2008
  4. kan3

    kan3 Well-Known Member

    COMPONENT INSPECTION:

    A quick visual inspection of the components of your chassis will make sure that your chassis will be able to be adjusted into the ballpark. You'll need to look closely at the following areas.

    Rear shock....Look for external physical damage to the shock itself. The main thing to look for though, is oil leaking around the shaft. Turn the rebound adjuster in all the way and push on the seat. You want to see a very slow return action. Turn the compression adjuster in (if so equipped), and the shock should feel stiffer.

    Front fork....Look for misalignment, nicks in the tubes, and damage to the sliders. Again your primary concern is oil leaking around the seals. Turn the rebound adjuster in all the way (if your bike has one) and look for very slow action. Turn the compression adjuster in (if so equipped), and the forks should feel stiffer.

    Tires....Look for irregular wear patterns. This can tell you a lot about the function of your chassis. They should be smooth and clean with no major visible irregularities.

    Wheels....These should be round, no dents, cracks (2mm of run out is the service limit, up and down, and side to side) inspect the wheel bearings anytime you remove the wheels.

    Brakes....Check for fluid leaks by pulling hard on the lever and keeping pressure on it for a minute or so. There should be no fluid escape at all. Use a high boiling point racing DOT 3 or 4 fluid. Look closely at your rotors and be cognizant of their wear.

    Chain and Sprockets....This is simply the most commonly screwed up service item on motorcycles. Most people have their chains too tight. It should have slop in it even when you sit on the bike. A worn chain is the recipe for disaster. Don't mess around with a worn chain.

    Steering head....An improperly adjusted steering head is simply dangerous. If it's too loose, the bike will wobble and wallow. If it’s too tight, the bike will "track" (go where it wants to on the straights) and not steer properly. Try and find an expert mechanic to assist you with this


    BASELINE SETUP

    At this point, we're finally going to do some measuring and adjusting. We will use a known working baseline to set up your chassis. Then the next time you practice, you will be able to analyze how it works and fine tune it to work even better. All suspension adjustments made by pushing or bouncing on the bike should be made with the bike off the stands, on level ground, and with the bike in neutral.

    Rear Shock....The first and most basic adjustment is to set the sag on the shock. When you make these measurements, accuracy is important. If at all possible, use a metric tape measure with millimeter increments. If you use an S.A.E. tape, then measure to the sixteenth of an inch (1" = 25.4mm). You need to pick two fixed points on the rear of your bike for this. One on the rear of the swingarm (like a stand spool or the axle), and one on the sub frame (like one of the bolts that holds the rear passenger pegs on. never use the bodywork since it can sag when the rider gets on). Before you can measure the sag, you must first find the fully extended measurement between your two points. Have a friend help you by pulling up on the footpegs to fully extend the rear suspension. Your bike may be fully extended already. If it is, this is not a problem. Record the distance at "full extension" on your log sheet. Now have your friend balance the bike for you and push down on the seat several times to settle the suspension. Now measure and record the distance between your two points again. This is your static sag. There should definitely be a little static sag on the rear shock. Most expert race bikes have 5-10mm static sag. Your next measurement is rider sag. Have a friend stand at the front of your bike and balance it by the ends of the handlebars. Sit on the bike like you would ride it and bounce down on it three times to settle the suspension. Now have another friend measure between your two points for you and log the measurement in the log. This is your rider sag. Next you need to subtract your rider sag measurement from your full extension measurement. This is your rear sag measurement. You should have 30mm of sag. This is your baseline setting and can be adjusted after your test ride. If your spring tops out the bike, you will need a stiffer spring.

    Now we need to adjust the dampening. The object is to get the suspension to respond as quickly as possible to irregularities in the pavement. Dampening is required to control the movement of the wheel and the spring. Set your rebound dampening adjuster first. It is difficult to explain how it should appear in words, but as you push on the seat, it should return quickly, but not instantaneously. It should take approximately one second for it to return to the top from a hard push. You should be able to watch the seat rise. If it just pops back up right away, you need to add rebound. If it drags up slowly, loosen it up. If you have a compression adjuster, sit it up in the middle. You can determine how to adjust it after your initial test ride, too hard loosen it up, and to soft add.


    Front Forks....Start here by setting the sag on the fork the same way you did on the shock. First you need a fully extended measurement. Only way to get consistency is to have two guys pick up on the handlebars until the front wheel leaves the ground slightly. Measure the exposed area of the fork slider. On a conventional fork, this will be from the bottom of the lower triple tree to the top of the dust seal on the slider. For an inverted fork, this will be from the dust seal down to the top edge of the aluminum axle clamp. Record this measurement on your log sheet. Push down on the fork hard three times, to settle the suspension. Now measure the static sag. Finally, get on the bike and push down three more times, while a friend balances the bike. Have your friend with the tape take the final measurement. The measurement you are looking for on the front fork is 35mm. If your spring is of the correct rate, the free sag should be about 65 percent of the rider sag, or about 20mm. The front fork has to have a great deal of free sag so that the front wheel may move down into a hole as well as over a bump. If your fork has too much sag turn the preload adjuster in. If you don't have preload adjusters, then you will have to remove your fork spacers and cut longer preload spacers. Adjust in 10mm increments. When you get close, you can go to 5mm increments.

    Next is the dampening adjustment. The fork needs to move much faster by comparison than the shock. Again, you should be able to watch it rebound, but not as slowly as the shock. Grab the front brake and push down on the front of the bike as hard as you can. Don't release the brake and don't resist the rising action of the fork. Observe the action. You want it to rise back as quickly as possible without topping out and settling back down again. Loosen the rebound until the bike does want to settle back after topping out, and then dial in just enough rebound to make that settling tendency go away.

    The compression adjuster should be set as softly as possible, but prevent the fork from bottoming over severe bumps or under hard braking.

    If you do not have these adjusters available to you externally, then you must change your fork oil weight to adjust the dampening. Thicker oil affects both compression and rebound dampening.

    If your forks works properly over bumps, but bottoms under hard braking, you can add more oil, or "raise the level" to help prevent bottoming. This reduces the air cushion you fork has above the oil.


    Steering Dampener....This is primarily a safety device and should be thought of as such and treated with great respect. Anyone racing without one might as well not wear leathers or a helmet. It's very dangerous. It should not be used to mask a bad handling motorcycle. When you go out to test your suspension, have the dampener set so that is barely drags when you sweep the wheel from side to side. It should not make your bike difficult to steer in the pits. Test ride the bike and analyze what it's doing before you crank up the dampener. A dampener that is too stiff will make the bike track from side to side and will be difficult to steer. After you make changes always return to this base setting, and then adjust.


    Jockey check....quick test method. Have a friend balance the bike while you get on and assume your riding position. Lift up off the seat slightly and bounce down on the bike. It should compress and rebound in a balanced fashion from front to rear evenly. If your bike isn't balanced, it won't work right. Your initial adjustments are only to get to this simple test. If the bike isn't acting balanced, adjust it until it does regardless of the initial adjustments you made. Balance is the single most important facet of chassis setup. A bike that is too soft or too stiff is still easier to go fast on than one that is out of balance. If you bounce lightly, it should act balanced, as well as if you bounce with great force.
     
  5. kan3

    kan3 Well-Known Member

    PERFORMANCE ANALYSIS/DIAL IN
    Now that you have a good baseline set-up, it's time for a test ride. Ensure that your tires have the correct pressure in them, and head to the track or your testing grounds. In order to make an assessment of your bike's chassis, you need to be conscious of what's going on while you are riding it. Someday when your a racing god, you'll have data acquisition equipment to tell your chassis engineers what to adjust. But until then, you are the only suspension sensor on your motorcycle. This is actually the best way to learn. There are several things you need to analyze as you ride.

    High speed stability.....this should be self explanatory, and the easiest to analyze. Go fast in a straight line and your bike should never scare you. If it does, you have some adjusting to do.

    Performance under braking....Is the bike stable? Does it squirm underneath you? Does the front wheel bounce? Does the rear wheel bounce? Does the forks bottom? How does the bike behave trail braking?

    Performance in the corners....This needs to be analyzed in three segments: Turn in, mid corner, and exit. Be conscious of these things within each of these segments: Overall stability, steering effort, ground clearance, front wheel action, and rear wheel action. That’s a bunch of stuff to think about, especially when you're just trying to circulate and learn to ride. If any of these things are out of whack, they'll usually let you know, consistently, in most turns. Here is an explanation of what to look for.

    Overall stability....The main thing to look for here is wallowing action. There should not be any. Wallow indicates a need for more spring.

    Steering effort....Does the bike track well in the corners? Do you have to fight to keep it on the racing/riding line? Are your arms completely worn out after riding/practice?

    Ground clearance....If you have anything dragging the ground, you have a problem that could result in injury. Some guys think they're cool because they drag stuff around the track/road. These people are a hazard to themselves and others. If you have anything dragging, fix it! Raise your footpegs, bend your pipe in, or
    whatever it takes. If you lean in hard enough on a bike that's scraping the ground you will lift a tire off the ground, and then you will immediately take its place on the pavement; this is serious business. If you are happy with the way your chassis works, then don't alter your ride height to stop things from dragging. Just get
    the dragging stuff up and out of the way. Changing ride height alters the bike's handling characteristics.

    Front wheel action....The wheel should roll smoothly through the corner and inspire confidence. Does the wheel bounce? If it does, you need to pay close attention to the way it bounces. If the wheel is bouncing and you can't really feel it in the bars, then this is a lack of rebound dampening. If the handlebars are jarring you, then
    you may have too much spring preload or compression dampening.

    Use rebound dampening carefully. Too much rebound dampening creates a situation where the fork is packing down. This means your forks has collapsed and is not re-extending fast enough. This is a VERY DANGEROUS situation. A fork that has packed down has no suspension travel left. A crash is eminent. You need to
    speed up your rebound dampening. You may also need a higher fork oil level, or more compression dampening to keep the forks from bottoming. This situation is usually set up by hard braking that compresses the fork followed by trail braking into the turn which never lets the forks recover. Some additional spring may help this too.

    Rear wheel action....Your rear wheel can exhibit many of the same symptoms as the front wheel. If your bike feels like a pogo stick then this is typically an all around lack of dampening. This condition will also cause a bunch of wheelspin on exit and tear up your tire. Wheelspin also fools riders into believing that they are going fast; that is until some novice on a GS500E goes railing around the outside of them in a turn. Too much rebound will cause the rear wheel to "swim" under the bike side to side under hard straight line braking. This is because the shock is packing up and the rear wheel is hanging in the air instead of returning to the ground to keep you pointed straight.

    A lack of compression dampening will cause the bike to pogo while under acceleration. This will be a vertical "sawing" motion; vertical relative to the bike even though it is still leaned over. Too much compression dampening will make the bike "buck" or kick you in the butt over sharp bumps. This can also cause excessive wheelspin. The shock should be soft enough to let the bike squat some. This transfer of weight helps give the tire more grip.

    When you notice a flaw in your suspension, note where it occurred in the turn. Was it as you rolled into the turn, was it in the middle of the turn, or was it as you accelerated out of the turn? This is critical information to help you (and a suspension tuner) decide what the correct changes should be.


    Chassis geometry....If your bike's chassis is soaking bumps properly, but your bike isn't steering around the track properly, then you need to adjust the "attitude" or "geometry" of your bike. This will affect it all the way around the track.

    The variables you have to work with are the fork height, and the swingarm angle. Here's what each does.
    Fork angle....Will increase or decrease your trail. Moving the nose of the bike lower (forks higher in the clamps) will make it steer faster, but will be less stable. Moving the nose of the bike higher (forks lower in the clamps) will require more steering effort, and will increase stability. Most expert riders say this increases "feel" at extreme lean angles.

    For most novice riders, will find it the easiest way to evaluate this is to ride through a high speed sweeper and evaluate how the bike steers into the turn and notice how much effort it takes to make it steer to the apex of the turn. In other words, "How does it hold a line?”

    If the bike is too low in the front, it will steer dramatically, and try and drive off the inside of the track. It will be unstable all the way through a turn, and sometimes even on the straight-aways.

    If the bike is too high in the front, it will steer in slowly and require that you pull on the bars to hold it down to get it to the apex. This condition will make it very difficult to steer the bike to the apex. It will fatigue your arms and they will feel tired after riding.

    Swingarm angle....tunes the way the bike reacts to acceleration. Your motorcycle wants to "squat" under acceleration due to the rearward weight transfer.

    If the swingarm is too flat, the bike will squat too much, and the bike will sit back and the front will extend like a "chopper". This will make the bike want to "run wide" or run off the edge of the track. The front end will feel light and dance about as you are leaving a turn. The result is that you have to wait to get on the throttle. You should raise the rear of the bike to correct this.

    If the swingarm angle is too steep, then the bike will not squat enough, and the result will be poor traction. This is "wheelspin" If you can whack the gas, and the wheel spins up, then you need to lower the back of the bike.

    Here's where it gets more complicated. Changing one end of the bike affects the other. There is a simple way to figure it out. If your problem occurs from steer-in to mid-corner, then change the front. If your problem
    occurs from mid-corner to the exit, then change the rear. Although there is no way to accurately mathematically describe what happens when you make a change, here is a VERY crude way to think about it.

    Changing the front ride height has an effect of "5" on the front and an effect of "1" on the rear. Changing the rear has an effect of "5" on the rear, and an effect of "1" on the front.

    A common example of where riders improperly change their bikes comes when the bike steers in too slowly. Many confused riders and tuners will raise the back of the bike. This makes the nose steeper, and the bike will steer more sharply. But remember, in order to get an effect of "1" on the front of the bike, you have now make an effect of "5" on the rear. Your bike may now turn in better, but you will get less traction, more wheelspin, and more tendency to high-side. This is not what you wanted... The correct change is to lower the nose of the bike. This affects the turn in "5 (front)" and the exit "1 (rear)". Much better!!!!

    If you have no idea where to start with your geometry, look around the pits or ask a suspension tuner. There is no correct answer or magic formula for what you personally want your bike to do. Your personal style of riding will dictate to you what to do with the bike. You will find that most production bikes are way off of what’s is generally "good" Find a range of "good" seems to be for your model of bike and start on the "safe" or "stable" side of the range.


    Traxxion Dynamics
    Max McAllister
     
    Last edited: Sep 29, 2008
  6. peakpowersports

    peakpowersports Well-Known Member

    Did you copy and paste all that or type it up?

    Nick
     
  7. kan3

    kan3 Well-Known Member

    Copy and Paste
    That information was written by Max McAllister from Traxxion

    It's actually kind of old
     
  8. panthercity

    panthercity Thread Killa

    Does Max not care aboout copyrights?
     
  9. kan3

    kan3 Well-Known Member

    Last edited: Sep 29, 2008
  10. craigcoble2000

    craigcoble2000 Well-Known Member

    WOW!!!! Good info but still not the one I was looking for......If there is anyone else who would like to post, please do so......

    Thanks.
     
  11. Smalls

    Smalls 2012 Blue...

    are you looking for the suspension flow chart?????
     

    Attached Files:

  12. Longhair

    Longhair Old Foole

    Or is this the one?

    SUSPENSION EFFECTS and ADJUSTMENTS

    Faster rider does not need more damping. Faster means quick enough moving suspension and just right damping.

    1. Set sag with rider aboard first, then check static sag with no rider (to affirm spring rate is within range).
    2. Set front compression then front rebound damping.
    3. Set rear compression then rear rebound damping, in that order.

    Sag: Warning, always have MORE FRONT sag than REAR sag, or at least have them equal. Avoid more rear sag than front sag especially with the SV
    Front: Rider on board = 32-33mm range 30-38mm. Static= 20mm range 18-24mm (less static sag hints at too soft a spring).
    Rear: Rider on board = 29-30mm range 25-33mm. Static= 8-9mm range 5-12mm (more static sag[if you ever see it] hints at too stiff a spring).
    These are numbers for a tight street setup for a fairly proficient rider. Easy going riders can use a bit more laden sag numbers, excluding static sag (as bigger static sag numbers could be too stiff a spring for rider weight, and not good for more laid back riders).
    In general problems coming into corners relate more to the front end, and problems accelerating out of them relate more to the back end (not completely applicable to front end tank slappers relating to reduced front wheel traction etc.).

    Stiction: If you have a friend help set sag and know how to measure your stiction, the range is
    0-10mm stiction front.
    0-5mm stiction rear.
    More than this and you may need a suspension service at that end of the bike.

    DAMPING:

    AFTER you have dialed in the front forks stand besides the bike holding the handlebar. Then you push down on the foot peg with your foot and the seat simultaneously with the other hand REAL HARD all your weight (don’t drop the bike). Set the rear shock compression and rebound so the bike goes down and returns at very similar rates in the rear to the front (goes down and comes up pretty level). One or the other should not apparently go down or return well ahead of the other. If the front goes down just a little bit faster than the rear, that will quicken steering coming into a turn though. Now the bike is ready to ride and adjust the rear shock further from ride testing.

    Compression damping front and Rear: Goal is to use as little as possible, and get a straight wound spring rate to do the bulk of the work in conditions where you are not braking. Make sure the fork spring rate isn’t stiffer acting than the rear spring rate though.

    Front compression: Use only enough to control bottoming and brake dive, get the right spring rate for your weight. A spring getting correct sag settings, and needing just a little bit of compression damping is good.
    When checking front compression on the road, see that hard braking doesn’t cause too much dive and test if the forks bottom on large-ish bumps.

    Front rebound: Use just enough rebound to keep from drifting wide at full throttle on low speed corners, and just enough to keep from topping out the forks. Use a little less than feels tight enough.
    When checking front rebound on the road, get on the brakes hard release normally and go to light throttle. The forks should not bounce up. Then check braking firmly to a turn, release turn in and go to light throttle, there should be no seesawing from the front.

    Rear Compression: Use only just enough rear compression to allow a small amount of squat on acceleration for traction and keep the bike from running wide on exit under acceleration. Avoid so little compression damping that it allows too much squat on acceleration during corner exit, and reduces traction and or alllows running wide on exit. Avoid so much compression damping the ride is over harsh, or traction is reduced on corner exit.
    Rear rebound: Use just BARELY enough to prevent wallowing in high-speed sweepers.
    __________________________________________________ ____________________________
    Compression Damping Adjustment –
    Adding more compression damping will make the shock firmer, more difficult to compress. Bumps will be felt more. Reducing the compression damping will make the shock feel softer.

    Rebound Damping Adjustment –
    Adding more rebound damping will cause the shock to uncompress slower. The shock will rebound slower. Reducing the rebound damping will cause the shock to extend faster.

    FORK ISSUES?ADJUSTMENTS:
    Set forks first then shock.

    Forks increase compression damping if:
    Front end dives over much under aggressive braking.
    Bottoming out over heavy bumps or under hard braking.
    Lack of feedback and vague feeling.
    Bike collapses into turn and needs correction to lean angle.
    Rear chatters or slews sideways under heavy braking on corner entry.

    (Increase compression in small increments until control is established).


    Forks decrease compression if:
    Bike steers wide on corner entry, feels hard to turn in.
    Front end chatters or shakes entering turns (also possible too high oil level, if oil is right decrease compression).
    Bike steers in sluggishly.
    Mid turn corrections tightening line require too much counter-steering pressure.
    Bumps are felt harshly through chassis up front and bars.
    Ride feels harsh up front and feels harsher braking over bumps.
    Front of bike skips or runs wide over multiple square edged bumps (could cause wash out of front).
    Front end shakes or tank slaps on corner exit having multiple bumps.


    Forks Increase Rebound if:
    Plush forks reduce control and or traction when speeds get high.
    Bike see saws front to back when brakes are released.
    Bike runs wide after releasing brakes or turns in poorly after releasing brakes.
    Front wheel feels like it’s washing out after brake release.
    Chassis disrupts and control is poor just after aggressive input at speed.
    Front fails to recover after aggressive input over bumpy surfaces.

    Forks decrease Rebound if:
    Ride is harsh.
    Road feedback is poor and feels dead.
    Bike front skips over multiple bumps of any type and steering quickens (could cause front end tucking, wash out or steering turn in and out).
    Steering gets quicker through the turn.
    Steering gets twitchy (more sensative) after you are in a turn for a ways, on little to no throttle (not when you are accelerating out smartly [this can happen more strongly when too much front rebound is combined with too much rear compression also]).
    Front end shakes or tank slaps on corner exit having multiple bumps.






    REAR SHOCK ISSUES/ADJUSTMENTS

    Reduce Rear compression damping if:
    Rear end feels jarring over ripples or bumps.
    Ride feels harsh (but not as harsh as too much rebound damping).
    The feedback from the rear tire feels vague over bumpy patches
    Rear spins and kicks up on exit especially over bumps, has less traction on exits, again especially bumpy ones.
    Rear end “kicks up” on sharp bumps hit at speed in turns or on straights.
    Rear end has poor traction during braking/deceleration.

    Increase Rear compression damping if:
    Slow turn in.
    Bike drifts wide on exit.
    Mid turn corrections tightening line require too much counter-steering pressure.
    Bike suspension feels sluggish.
    Bike squats too much when cornering.
    Less acceleration traction.
    Rear end squats excessively during acceleration.
    Rear end bottoms out over bumps.

    Reduce Rear rebound damping when:
    Bike runs wide on exit.
    Ride feels quite harsh.
    Rear end feels vague.
    Rear kicks up over multiple bumps on exit.
    Rear end has poor traction during acceleration, tire spins.
    Rear hops and skips on corner entry.
    Rear end packs down in bumpy corners.
    Rear feels like it’s getting lower after each bump, and ride feels harsher after each bump.
    Tire wear has a band of tearing tread an inch or so up from the edge of the tire.

    Increase Rear rebound damping when:
    Bike wallows or lurches on high-speed turns.
    Bike wallows or lurches mid turn on long lasting bends.
    Rear end “jacks up” under braking and feel like it’s riding too high in the rear.
    Rear end “bounces” after a bump (i.e. pogo stick feeling).
    Rear end seems to deflect or kick off of multiple sharp edged bumps.
    Rear end feels soft at low speeds but harsh at high speeds.
    Rear end feel like it hops, skips or weaves during hard braking
    (***Note This can also be caused by too little compression in front forks)

    Lastly:
    Of course chassis geometry, weight distribution (especially of rider), chassis stiffness, throttle position, and steering input also play a part in these things.
     
  13. GixxerBlade

    GixxerBlade Oh geez

  14. goodmatt78

    goodmatt78 Well-Known Member

    I would like to see an updated article with the use of both High and Low speed compression.
     
  15. dusty20

    dusty20 #97 North Central Ex.

    according to David Moss on the introduction to suspension video highspeed is basically not adjustable his best recomendation is to screw it all the way out, then screw it in 2/3 of the way and leave it. I would assume he would know the best having looked at suspension on dyno's and tuning for different teams.
     
  16. Dr. GoFast

    Dr. GoFast Well-Known Member

    ^^ i think he was talking only about the stock yamaha highspeed damping adjuster if i remember correctly though. he was saying it's just there to look cool and that it doesn't actually do anything. i'm sure ohlins, etc... highspeed adjusters DO work tho..
     
  17. JP OTTO

    JP OTTO Well-Known Member

    I've heard that as well and that to me seems like a very bold statement. (or a good way to sell Ohlins 25 kits that have no high speed adjustments) And as far as Ohlins go, it sounds like a $2500 downgrade when you loose high speed adjustment. Why wouldn't you want it? Or maybe you do want it if it works. I've also heard that Ohlins doesn't have the HS adjustment because most the GP/European tracks are super smooth, where as in the States we have some bumpy ass tracks that can use the separate adjustments and maybe US tracks aren't Ohlin's focus. I don't know for sure.

    (Please don't take this as me talking SH#T it's just that I would really like to know as well)

    Jim at Lindeman Engineering Suspension (le-suspension.com) told me that the 06 R6 HS comp doesn't really work that well. It's not to say that it wouldn't work, it's just that the shim stack and small spring need to be replaced. So, I purchased his comp kit, installed it, and it works awesome! I can see it working. I put a tie wrap on the fork tube and easily adjust for the big bumps with the HS comp by checking the position of the tie wrap. (If I feel a harsh bump and the forks aren't bottoming then I back out the HS so the fork can move a little faster and soak up the bump) IMO it works. This is the newest bike I've owned and I'm drooling over all the new technology. (I've also have a '76 TZ250 that is very low tech in comparison)

    I'm just starting to learn about suspension so I'm just talking from my experiences. I'm not trying to be a know it all cause I don't really know too much. I just really like to gather info on suspension. So please chime in if this info seems wacked out!

    (sorry for thread jacking):tut:

    .
     
  18. JP OTTO

    JP OTTO Well-Known Member

    I forgot to say thanks for posting the suspension tuning info. It's a lot easier to read than the notes I look!!!!
     
  19. 4yamahas

    4yamahas Well-Known Member

    The hi-lo doesnt work , thats why T man takes it out. 25MIL Kit with out the hi-lo works great and is lighter , less unsprung weight.
    I would like to see hi- lo adjustment of rear shocks discussed .
     
  20. JP OTTO

    JP OTTO Well-Known Member

    What exactly doesn't work with the H/L? I keep hearing people say it doesn't work with out any explanation. Is it like a 2x4 for front forks or a pogo stick? It seems to work to me but then again I may not be sensitive enough to make that call and I've never tried the Ohlins 25 kit in an R6. There are some guys that go faster with re-valved stock stuff than Ohlins. I guess it comes down to preferences and rider styles? There is a lot of conflicting information coming from many top level tuners. Maybe there is no right answer?

    As far as the rear stock shock goes. I was told (lol) that there is not enough HS. I have mine turned all the way in. It seems to work great.

    anyone else?
     

Share This Page