Suspension 101 : Suzuki GSX-R Motorcycle Forums: Gixxer.com
» Insurance
» Suzuki GSX-R Prices
» Sponsors
Go Back   Suzuki GSX-R Motorcycle Forums Gixxer.com > Tech Forums > Chassis, Suspension & Tire Setup

Reply
 
Thread Tools Display Modes
Old 07-10-2005, 04:14 AM   #1
Gixxervan1000
Rookie
 
Join Date: Dec 2002
Location: San Antonio TX
Motorcycle: Gixxervan1000
Posts: 816
Suspension 101

Hey guys, I got this from someone on this board a long time ago...just came across it again. Since the same questions are asked time and again I thought this would be a good sticky. Hopefully Im not infringing on any copyright laws since I have no idea where this exerpt originally came from. If I am, Im sure one of the mod's will delete the thread quickly.
__________________________________________________ _________________________

Suspension 101.

Introduction

Unfortunately there is no literature that can give you the perfect machine setup. Also suspension setup is individually dependent on the rider (style, preference) and track conditions, which vary from race to race. We can therefore only try to give you guidelines and ground rules for the chassis setup of your machine.

General guideline
The general guideline in road racing is that the suspension has to support the tires to create the best possible grip. For this reason suspension plays it's most important role in corners, chicanes, acceleration and braking. In the straight line the suspension works satisfactory if it can absorb the bumps without causing instability.

Suspension stroke
A road race bike should normally not use its full suspension stroke, although on some circuit one or two big bumps or hollows can cause the suspension to bottom. Also landing of front wheel after wheelies can cause excessive use of the front fork stroke. If suspension bottoms in big bump or hollow, it should not automatically mean that the suspension should be set harder. However, if suspension bottoms at the place were the maximum grip is essential the tire cannot create the best traction, because it also has to perform as spring. Adjusting the setting is necessary. During every riding session the suspension stroke should be carefully checked. When tire grip and lap times improve, the suspension has a harder job. So, setting must be set harder. On the opposite, when it starts raining tire grip and lap times go down, in that case a softer setting should be applied.

Suspension setup
Before starting suspension setup, read the owners manual!
A tip, do your changes in suspension setup one by one, try to learn what effect each individual adjustment has on your bike and take notes!

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

Note: An RR 125 cannot afford to loose the momentum that the sag would give in a straight line (loss of top speed). The static sag is adjusted by the spring preload. The procedure is the same for the front fork and rear shock.
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.

Note: Ohlins racing shocks features a "top-out" spring to prevent the shock from extending to quickly, causing the rear wheel to jump under braking. The top-out spring also affects the negative sag, making it difficult to adjust the sag with the shock on the bike.

Your Ohlins shock is delivered with the correct spring preload set and we recommend you to use this value for the basic setup. Ride height should be adjusted with the ride height adjuster on the bike or on the shock.

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.


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




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.


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 itís 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.


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. Thatís 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?Ē

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 whatís 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.


CONCLUSION

With this information you should have a good idea what's going on with your bike on the track or street. Here's the bad news: You will always be adjusting it if you want to go faster!!!! DO NOT be afraid to make changes!!! You will never learn or improve if you don't. Nothing you do will make you go out and crash unless you are stupid. Make a change, and then slowly build up to your pace over a couple laps to feel out the difference. If it doesn't feel better to you, then come in and change it back. If it does feel better, you may still want to change it back to be sure it did. It is easy to convince yourself you made your bike "better", because you want it to be. This is how most people get "lost".

If you make a change and go out and crash, it is not because you made a change. You crashed because you crashed. If you think about it professional riders, they get different springs, forks, and shocks all the time. They aren't usually just making simple little changes. If you could crash from a few simple clicks of rebound or a turn of ride height, then pro riders would never finish practice! The point is not to be scared to make changes.

Make notes after you get off the bike while your thoughts are clear in your mind. If you are unsure about which way to go with your adjustments, your notes will be helpful to you when you seek advice. Keep a thorough log of all of your changes. The next time you return to the same track, you'll be able to set up better before you get there. You'll find that a properly set-up chassis will be worth more than all the horsepower money can buy!!!!!!!!!!!!!!!!!!!!!!

Traxxion Dynamics
Max McAllister
Gixxervan1000 is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 07-12-2005, 04:31 AM   #2
bmfgsxr
Highly unstable admin
 
bmfgsxr's Avatar
 
Join Date: Apr 2001
Posts: 32,025
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

that is great stuff for sure..
bmfgsxr is offline   Reply With Quote Quick reply to this message
Old 07-12-2005, 05:40 AM   #3
Gixxervan1000
Rookie
 
Join Date: Dec 2002
Location: San Antonio TX
Motorcycle: Gixxervan1000
Posts: 816
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

I thought so. I don't remember who PM'd it to me on here, but I just want to say thanks because it's helped me out A'LOT. Just wanted to return the favor.
Gixxervan1000 is offline   Reply With Quote Quick reply to this message
Old 07-12-2005, 06:02 AM   #4
Sexfreak1k
Club Racer
 
Sexfreak1k's Avatar
 
Join Date: Mar 2003
Location: AL
Motorcycle: aka RSIXER
Posts: 2,347
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

i watched the video my buddy bought while we were at the facility. pretty sightful information
Sexfreak1k is offline   Reply With Quote Quick reply to this message
Old 07-12-2005, 09:28 AM   #5
Philbie
Rookie
 
Philbie's Avatar
 
Join Date: Sep 2003
Location: Mesa, AZ
Motorcycle: POS 04 GSXR
Posts: 1,338
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

I think Quig was the guy who was sending it out. I know he posted it as a link under "Reading Material" in this forum.
Philbie is offline   Reply With Quote Quick reply to this message
Old 07-15-2005, 08:18 PM   #6
GSXR ONE
Rookie
 
Join Date: Apr 2005
Location: Sunny Weather
Posts: 466
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

Quote:
i watched the video my buddy bought while we were at the facility. pretty sightful information
Wasn't that the longest video!!!!!!!!!!!! Very helpful and worth the money, but hella long.
GSXR ONE is offline   Reply With Quote Quick reply to this message
Old 07-16-2005, 12:51 AM   #7
Gixxervan1000
Rookie
 
Join Date: Dec 2002
Location: San Antonio TX
Motorcycle: Gixxervan1000
Posts: 816
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

I still might get the vid...but I figure the written info is just the same.
Gixxervan1000 is offline   Reply With Quote Quick reply to this message
Old 07-16-2005, 03:35 PM   #8
WebCrush
Superbike Champ
 
WebCrush's Avatar
 
Join Date: Feb 2001
Motorcycle: 2004 CRF450r SuperMoto
Posts: 9,968
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

Kinda lame that this forum is monitored and created for GMD Computrack, a site sponsor, yet you sticky stolen info from Traxxion on here.

WebCrush is offline   Reply With Quote Quick reply to this message
Old 07-18-2005, 04:17 AM   #9
bmfgsxr
Highly unstable admin
 
bmfgsxr's Avatar
 
Join Date: Apr 2001
Posts: 32,025
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

kinda lame that your bitching about info that will help all riders regardless of who its from.. if pete has an objection about it then he can get in touch with me, and mr. gixxer and we will do what ever we have to. so go roll your eyes somewhere else mr. friendly.
bmfgsxr is offline   Reply With Quote Quick reply to this message
Old 07-18-2005, 06:11 AM   #10
Gixxervan1000
Rookie
 
Join Date: Dec 2002
Location: San Antonio TX
Motorcycle: Gixxervan1000
Posts: 816
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

Not to mention the fact that the "info" truly isn't stolen since almost every suspension shop has the same information. This guy just happened to write it all in a concise format.
Gixxervan1000 is offline   Reply With Quote Quick reply to this message
Old 07-18-2005, 11:29 AM   #11
WebCrush
Superbike Champ
 
WebCrush's Avatar
 
Join Date: Feb 2001
Motorcycle: 2004 CRF450r SuperMoto
Posts: 9,968
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

Quote:
kinda lame that your bitching about info that will help all riders regardless of who its from.. if pete has an objection about it then he can get in touch with me, and mr. gixxer and we will do what ever we have to. so go roll your eyes somewhere else mr. friendly.
Peter doesn't raise objections, he leaves that job to me.

Either way, sponsor loyalty seems to go far here
WebCrush is offline   Reply With Quote Quick reply to this message
Old 07-19-2005, 02:50 AM   #12
Gixxervan1000
Rookie
 
Join Date: Dec 2002
Location: San Antonio TX
Motorcycle: Gixxervan1000
Posts: 816
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

See I thought this forum was about talk of suspensions and chassis development in general.

I didn't know it was a fishing pond for one particular suspension place to lure in customers.

Now that you mention it, I have noticed that most of the advice ends in something like "...you should send it here to get worked on....". Nothing wrong with that, the guy run's a busines so it's a logical thing to do. But when REAL advice is is not given in lieu of a sales pitch, that's where I call bullshit. Some problems WILL require the shop's assistance, but many will not with some simple understanding.

I thought Pete was a moderator because he liked talking about suspensions and helping others regardless of whether he gets paid from it. From what you're saying maybe not.
Gixxervan1000 is offline   Reply With Quote Quick reply to this message
Old 07-19-2005, 10:15 AM   #13
bmfgsxr
Highly unstable admin
 
bmfgsxr's Avatar
 
Join Date: Apr 2001
Posts: 32,025
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

sponsor loyalty does go far here so go roll your eyes someplace else adam. dont be so gay man..
bmfgsxr is offline   Reply With Quote Quick reply to this message
Old 07-22-2005, 07:56 AM   #14
Northwind
Back Marker
 
Join Date: Apr 2005
Posts: 100
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

Can't see what the big deal is... If it said "Come and buy my parts" then that'd be one thing, but it's good general advice. You could use parts from Max of from the sponsor and the directions would remain the same. If the sponsor wants to add better advice, then I'm sure everyone would listen.

If anything, this article's likely to help make the sponsoir business, since people will read it and think "OK, time to upgrade my suspension" then look around for a source for parts. If it weren't for the responses I wouldn't even have noticed the advice was from Max.
Northwind is offline   Reply With Quote Quick reply to this message
Old 07-22-2005, 08:17 AM   #15
MY02gsxr1000
Club Racer
 
MY02gsxr1000's Avatar
 
Join Date: May 2003
Location: LINY
Motorcycle: 02 Gixxer 1K
Posts: 3,291
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

Quote:
Kinda lame that this forum is monitored and created for GMD Computrack, a site sponsor, yet you sticky stolen info from Traxxion on here.


I didn't see anywhere that this forum was set up for GMD, maybe it should have be titled Chassis and suspension set up by GMD if it was set up for them. I see plenty of post by GMD offering advice to people for free and I see nothing wrong with him saying send me your work. I'm sure helping people is not his hobby but his living. I am also a site supporter does that mean any good advice should come from GMD? I could have copied and pasted this from a book would I also be wrong for putting this info up? I happen to think GMD offers a good service I know people who have used them but I think your taking this a little to far. If GMD sponsers you, then good for you and good job standing up for your sponsor but lets not get silly-crazy over good advice for everyone. Thats what this site is about or atleast thats JMO.
MY02gsxr1000 is offline   Reply With Quote Quick reply to this message
Old 07-27-2005, 12:36 AM   #16
bmfgsxr
Highly unstable admin
 
bmfgsxr's Avatar
 
Join Date: Apr 2001
Posts: 32,025
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

bottom line is pete from gmd computrack is a really good guy. i have personally done business with him in the past, and will again in the future..

i also know max, and he didnt seem like a bad guy when i met him.. although i personally wouldnt have him do work for me. but that has more to do with the fact that pete is more local to me and is always at my home track and will help set up a bike he has done work for.
bmfgsxr is offline   Reply With Quote Quick reply to this message
Old 08-16-2005, 09:02 AM   #17
RussZTT
Non Bearded Super Moderator
 
RussZTT's Avatar
 
Join Date: Apr 2000
Location: Jacksonville, Fl
Motorcycle: 2003 Copper and Black 1000
Posts: 41,577
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

I thought it was great information no matter where it came from. However I don't think doing suspension tips is a secret.
RussZTT is offline   Reply With Quote Quick reply to this message
Old 08-29-2005, 06:29 AM   #18
rideordie4life
Novice
 
rideordie4life's Avatar
 
Join Date: Aug 2005
Location: ND
Motorcycle: 2005 gsxr 1000
Posts: 50
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

I have a 2005 gsxr 600 and was wondering why suzukis are the only bike from factory i cant clutch up in second without standing up. Why are suzukis like this is it the suspension that has something to do with it and is there a way i can adjust it.thx
rideordie4life is offline   Reply With Quote Quick reply to this message
Old 10-01-2005, 12:58 AM   #19
bmfgsxr
Highly unstable admin
 
bmfgsxr's Avatar
 
Join Date: Apr 2001
Posts: 32,025
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

its technique man.. it has nothing to do with suspension.. ive seen plenty of guys clutch up the gixxers. although i never clutch up a wheelie, just power it up.
bmfgsxr is offline   Reply With Quote Quick reply to this message
Old 12-18-2005, 12:59 PM   #20
gsxr_45
Rookie
 
gsxr_45's Avatar
 
Join Date: Dec 2004
Location: N. Vancouver
Motorcycle: K5 K1 / K3 K1 / HRC RS250R GP/ APE RSZ / 02 954 / 05 Husky 450 TC /
Posts: 461
Re: Suspension 101 from Traxxion Dynamics Max Mcallister

thankx for the input, it's riders like your self thats helping us keep coming home . my k3 is set up by the seat of the pants trail and error , rails like a dream and does,nt do anythinkg stupid , the best bike i,ve ever owned or rode , i run pro corsas on the street and will never run anything other than d.o.t. ,s all hooked up is part of alot of suspenion woos ,so faster riders will have to be awear of this at both ends posers and lunitics . thankx again , ride safe ride free p.s. i have rode a k5 love it great track bike fits me perfectly , i'm ok with my k3 with some mods for the street and some track days / i.m going to get a 250 tz for the crazy racing lol lol peace
gsxr_45 is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Suzuki GSX-R Motorcycle Forums Gixxer.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in


Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Powered by vBadvanced CMPS v3.2.2

All times are GMT -5. The time now is 07:07 AM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright © 2008 ó 2013 Gixxer.com
Motorcycle News, Videos and Reviews
Honda Grom Forum Harley Davidson Forum Honda 600RR Forum Kawasaki Forum Yamaha R6 Forum Yamaha FZ-09 Forum
1199 Panigale Forum Roadglide Forum Honda CBR1000 Forum Vulcan Forum Yamaha R1 Forum Yamaha R3 Forum
Ducati Monster Forum Harley Forums Honda CBR250R Forum ZX10R Forum Star Raider Forum Yamaha Viking Forum
Suzuki GSXR Forum V-Rod Forums Honda Shadow Forum Kawasaki Motorcycle Forum Star Warrior Forum KTM Duke 390 Forum
SV650 Forum BMW S1000RR Forum Honda Fury Forum Kawasaki Versys Forum Drag Racing Forum Ducati 899 Panigale Forum
Suzuki V-Strom BMW K1600 Triumph Forum Victory Forums Sportbikes BMW NineT Forum
Volusia Forum BMW F800 Forum Triumph 675 Forum MV Agusta Forum HD Street Forum Suzuki GW250 Forum
Yamaha Motorcycles Victory Gunner Forum Honda Vultus Forum HD LiveWire Forum Ninja H2 Forum Ducati Scrambler Forum Kawasaki Ninja 250SL Forum