WARNING: EPIC POST!Ok, this is mostly cut and paste of stuff I have collected over a few years. I found it helpful as
I am definitely not an expert by any means, I just thought I would share it. Some of it may apply to you, some of it may not. So please do not ask me for any advice as I am not qualified to give it.
The standard general disclaimer applies, you do this at your own risk, myself and anyone involved with this forum will not be held responsible for anything you do or as a result. All I can add is no matter what you do be aware your bikes handling may change dramatically and be careful riding it after adjustment, always record everything you changed to quickly return to where you were before. This is a general guide only, take it or leave it, if you trash your bike then that is your fault so don’t post here that I caused it
It is a lengthy read so i suggest printing it out if you are going to use it, each subsequent post may cover the same ground as the others so forgive me for redundant information. ............... Read on...
Here goes....................................
SUSPENSION SETUP EXPLAINED The suspension setting process provided here is a "Basic" methodical guide to providing a way to update you current suspension to the style of riding to best suit your needs. When suspension works correctly the bike will be much more enjoyable to ride.
One of the major keys to a successful suspension setup is the condition of the components. Before attempting any setting changes, check to make sure your bike's fork and shock are in good working order. This includes replacing leaky seals, lubricating sticky linkage bushings, and changing old fork or shock oil. If your current components have more than 15,000 hard miles on them, you can bet it's time for a rebuild. Check your steering head bearings for notchiness or tightness and replace them if needed. And most importantly, squared-off or worn out tyres will mask almost any suspension change you make.
The following is an outline of the major steps that will be taken to bring you bike into a good riding setup that will help you enjoy your riding experience.
Steps of the Game
The following sections of this article go into the dynamics of what happens when changes are made to the suspension. I state that the adjustment process is a game because of the tradeoffs that must be made. There are tradeoffs that can be given for each adjustment that you make to your bike. These trade-off must be balanced against the gains that a specific adjustment makes to improve your suspension.
TYPES OF RIDING
The types of riding determine you expected setup. As a street rider typically expects a more compliant and plush suspension that needed to soak up the rougher roads and to be more comfortable while riding. This more relaxed stable setup will actually help over the long haul of street riding because of less rider fatigue with a stable. Track riding has different goals of pushing the bike so it provides the optimum effectives for the track. The track does not translate directly into a good street bike and vice versa.
Determining the style of the rider also affects the way your setup reacts for a particular person. A smooth rider will have a different setup compared to a point and shoot style of riding. It is all relative to you and your bike.
It's important to take good notes--and lots of them, especially for the track. Along with your initial settings, you should also write down some baseline figures for things such as fork oil weight and amount, ride height, spring rates, and so on. Record any changes you make so that you can refer to them later. Also, keep notes for different types of riding street, touring, tracks--as your setup will change depending where you are and the conditions. Once you find that "magic" setup, don't be afraid to deviate from it and experiment; you may be able to improve on what you have, and you can always go back to what you wrote down in your notes.
STREET SETUP
The first step to a good setup is setting static sag. For street purposes, front sag should generally be between 30 and 35mm, and rear sag between 25 and 30mm. Don't vary from these numbers if you're heavier or lighter--that's the whole idea of measuring sag while you are on the bike. An easy way to check if your shock spring rate is in the ballpark is to measure the rear "free" sag, that is, the sag without your weight on the bike. This number should be between 0 and 5mm--with the bike off its stand and on its own, you should be able to lift the rear end just slightly and top out the suspension. If your bike is topped out at rest, you need a stiffer spring, because you have got a lot of preload dialed in to achieve the correct static sag. Alternately, if your bike has a lot of free sag (you can lift the rear a bunch before it tops out), you need a softer spring.
Rebound damping can be initially set as follows: With the sag properly set and the bike at rest and off its stand, firmly push on the triple clamp (don't hold on the brake or push the handlebar) or seat. When you let go, the suspension should rebound quickly to its original position--but not beyond. If it takes more than approximately one second for the suspension to return to position, less rebound damping is needed. If the fork or shock over-extends past its free sag, and then compresses again, more rebound damping is required. Street riding entails many different pavement characteristics, and the road is generally bumpy compared to a racetrack, so it's better to err on the soft side if you are unsure. This will also give you the added benefit of a smooth ride for daily use; you can always dial in a tad more rebound when you get to your favourite road where the surface is more of a known quantity.
Compression damping can be initially set as follows: It is difficult to set compression damping without riding your motorcycle and feeling how its suspension works. What feels nice and plush at a standstill may turn out to be too harsh at speed, and compression damping is sometimes set by personal preference as opposed to a definite optimum. Start with the compression adjusters in the middle of their adjustment range, and take your bike for a spin. Working with the front and rear individually, soften the damping adjuster, and try your bike again over the same road. Is your handling better? Worse? The same? Try again, this time with the damping stiffer than what you started with. Continue experimenting, making adjustments accordingly. As with rebound damping, it's always best to err on the light side with compression, and for the same reasons.
One final check--with your bike off its stands, place your hands near the rear of the tank, and push down. A well-balanced setup will have both ends of your bike compressing and returning at approximately the same rate with this push. If the front compresses or rebounds different than the rear, attempt to match them, keeping within the parameters established individually.
TRACK SETUP
As with the street setup, first ensure that your bike's suspension components are in good working order, and you have relatively new tyres installed. One word of caution regarding setup and tyres: Don't get dragged into adjusting your suspension to account for tyre wear over the course of a track day without taking notes. You'll be amazed at how poorly your bike handles when you put new tyres back on and keep the shagged-tyre suspension settings.
In general, a bike set for track use is stiffer than a streetbike, due to the increased acceleration, braking and cornering forces involved. Static sag for track bikes should be in the range of 25 to 30mm--somewhat tighter on the fork than a street setup. Similarly, compression and rebound damping should be somewhat stiffer. Avoid tightening your rebound arbitrarily; you still want the suspension to rebound within one second to its static position after pressing on the bike, but not overshoot.
Ride Height can be initially set as follows: If you have a ride height adjuster on your aftermarket shock, set it to the same length as the stock unit for a start. Similarly, begin with your fork at the stock height in the triple clamps. Use the handling scenarios and the chart to determine if you need to change your bike's attitude. Generally, for a track bike with a steering damper, you'll want to quicken the steering as much as possible by lowering the front end or raising the rear, while still retaining stability and without sacrificing rear end traction.
Prior to making suspension changes
There are a few adjustment to your bike setup that should be done prior to making adjustments to your suspension. These adjustments could affect handling to a certain degree, and throw off getting the proper feedback. As stated earlier in this article it is important to have your bike in proper running order.
Fill out the check sheet
Check chain alignment. If not correct, sprocket wear is increased.
Proper tyre 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.
Chain Adjustment: Proper chain adjustment minimally affects the overall length of the rear swingarm. Although this is not significant it is a factor because of other the proper chain tension can have an impact on how the suspension reacts. This negative effect has become less pronounced with new motorcycle models because of the suspension pivot being located so close to the counter shaft.
MAX EXTENSION You should check the chain tension with the bike on its wheels and preferably with someone sitting on it. You want the chain at maximum extension - or with the front sprocket, swingarm and rear sprocket all in line with each other.
It probably won't be lined up perfectly, but plonking yourself in the saddle and using your own weight (or that of a friend) is a good start. Wiggle the lower run of the chain as close as possible to the middle. You should have about 15-20mm of slack up and down.
WHY BOTHER? Good question. A tight chain will place a lot of unnecessary strain on itself, the sprockets and even gearbox bearings. Keep running chains too tight and you can do a lot of expensive damage. Have it too loose and you risk the chain thrashing around and causing increased sprocket wear or, in a worst case, throwing itself off the sprockets altogether and causing a crash.
A well adjusted and lubricated chain transmits the power smoothly (you can actually see the difference on a dyno), lengthens the service life, smoothes out your gear changes and makes the bike feel better to ride.
Wheel Alignment:
If you have a conventional chain-drive bike, you'll see the back wheel's position can be altered with the adjusters. Whenever you tension the chain or move the wheel for any reason, you generally just line it up against the alignment marks stamped on the swingarm. If the axle is back three-and-half notches on one side, you make sure it's back three-and-a-half on the other. Simple.
The trick is to get a ball of twine, or you can do this exercise if you can somehow find two straight edges that are longer than the bike. The latter is a big call, so we'll stick with the string method - yep, this is ye olde "stringlining", of which you may have heard your mates speak.
Usually this is easiest with the bike on the side stand (the center stand usually gets in the way) and propped up as close as possible to vertical. A race stand is often a good option.
Wrap the string around the front of the front wheel, as high as possible without snagging fairings and associated under-bike hardware when you run each end of the twine under the machine. The pics will give you the idea.
From there the plan is to get the front wheel straight, and then the rear wheel adjusted so it is too. What you want to end up with is what we've shown in the main diagram - where the distances "A" (the gap between the string and the edge of the tyre) and "B" (ditto) on the trailing edge of the front wheel are equal to each other; And the distances "A" and "B" on the trailing edge of the back wheel are equal to each other. (Note: the A/B up front does not have to match A/B on the back.)
This is often best done with two people, one working on each end of the bike. It is a great help to have oil cans/bricks/jackstands to hold the loose ends of the string for you while you fiddle.
Getting it all lined up will be a bit of a fiddle, but simple enough assuming the bike is straight. The exact method isn't critical, so long as you end up with a result that looks like our diagram.
If you cannot get them to align, it is likely the frame isn't straight, or the bike might even have been designed with the rear wheel offset from the front.
Tyre Pressure:
You'll get a lot of opinions on what tyre pressure to run, but the correct tyre pressure for you is not a matter of polling other rider's opinion. Here are the basics you'll need to decide for yourself. Dennis Smith of Dunlop's Sport Tyre Services recommends an increase of two to four pounds in front tyres and six to eight in the rear. While the most scientific means of determining if a particular pressure is the use of a pyrometer to assess whether the rubber has reached the manufacturer's recommended temperature, charting the pressure increase of a tyre after track sessions will give a good impression of how hard a tyre is working.
Stamped on the outside of many of your tyres is a recommended tyre pressure range. (At least an upper limit.) For longest tyre life it is my recommendation that you strive to keep them at the higher limit of those recommendations (regardless of what your motorcycle owner's manual might say to the contrary.) Further, this pressure should be determined while the tyres are cold - meaning, have not been used for a couple of hours.
Start with the bike manufacturer's recommendation in the owners manual or under-seat sticker. This is the number they consider to be the best balance between handling, grip and tyre wear. Further, if you're running alloy wheels on poor pavement, consider adding 2 psi to the recommended tyre pressure just to reduce the likelihood of pothole damage. Just as you would for a car, increase the pressure 2 psi or so for sustained high speed operation (or 2-up riding) to reduce rolling friction and casing flexing.
In order to get optimum handling a tyre has to get to its optimum temperature, which is different for each brand of tyre. Most of us don't have the equipment needed to measure tyre temperature directly so we measure it indirectly by checking tyre pressure since tyre pressure increases with tyre temperature. Tyre temperature is important to know because too much flexing of the casing of an under-inflated tyre for a given riding style and road will result in overheating resulting in less than optimum grip. Over-pressurizing a tyre will reduce casing flexing and prevent the tyre from getting up to the optimum operating temperature and performance again suffers. Sliding and spinning the tyres also increase tyre temperatures from friction heating.
A technique for those wanting to get the most out of their tyres on the street is to use the 10/20% rule.
First check the tyre pressure when the tyre is cold. Then take a 30-40 minute ride on your favorite twisty piece of road to get your tyre temperature up, then measure the tyre pressure immediately after stopping.
If the pressure has risen less than 10% on the front or less than 20% on the rear, the rider should remove air from the tyre (to increase heating affect of carcass flex). So for example, starting at a front tyre pressure of 32.5 psi should bring you up to 36 psi hot. Once you obtain this pressure increase for a given rider, bike, tyre, road and road temperature combination, check the tyre pressure again while cold and record it for future reference.
Each manufacturer is different. Each tyre model is different.
A tyre design that runs cooler needs to run a lower pressure (2-3 psi front) to get up to optimum temperature. Remember carcass flex to generate additional heat.
The rear tyre runs hotter than the front tyre on both road and track. So the rear tyre cold-to-hot increase is greater.
Dropping air pressure has the additional side effect of scrubbing more rubber area, and can additionally add more traction at the cost of a little stability
As an example for aprilia RSV Mille recommended starting temperatures for road use are.
Front Tyre 34.8 deg. Cold which in turn should be approximately 37.5 -38.5 deg Hot (3-4psi increase)
Rear Tyre 39.4 deg Cold which in turn should be approximately 45-47 deg Hot (7-9psi increase)
For the track you'll have to drop the cold tyre pressures an additional 10/20%. Track operation will get tyres hotter (increasing the cold-to-hot pressure range) so starting at say 32/30 psi now should bring you up to the same temperature (and pressure) that 35/39 psi gave you for the street.
Since track riding put tremendous stresses on a tyre the tyre heats up more than if it was on the street. run at a racetrack, unless of course you're running a race tyre. The lower the tyre pressure the more the tyre deforms. The more the tyre deforms, the more friction there is between the tyre and the road surface. The more friction, the more heat. The more heat, the greater the opportunity the tyre has to regenerate itself by shedding the 'used' layers of rubber (to a point). This deformation of the tyre also creates a bigger contact patch at the cost of a little stability.
When you are accounting for your riding style and the way different days, streets, tracks can be accounted for. All bikes will have different characteristics which means my starting riding temperature is different than yours.
Additionally with the colder months of the year tyre pressures and the effect of temperature can greatly affect the overall pressure.
Time and outside temperature effect the pressure within your tyres. It is NORMAL for a tyre to lose about 1 pound per square inch (psi) per month. Outside temperatures affect your tyre pressure far more profoundly, however. A tyre's pressure can change by 1 psi for every 10 degrees Fahrenheit of temperature change. As temperature goes, so goes pressure.
For example, if a tyre is found to have 38 psi on an 80-degree mid-summer day, it could lose enough air to have an inflation pressure of 26 psi on a 20-degree day six months later. This represents a loss of 6 psi over six months and an additional loss of 6 psi due to the 60 degree temperature reduction.
At 26 psi, your tyre is severely under inflated and dangerous!
What is being illustrated here is that you MUST check your tyre pressure on a regular basis (about once a week is reasonable) and to be particularly aware of it on cold days
Reference of James R. Davis, sportsrider.com, Larry Kelly mad-ducati.com
Suspension stroke
A sportbike 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 more hard. However, if suspension bottoms at the place were the maximum grip is essential the tyre 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 tyre grip and lap times improve, the suspension has a harder job. So, setting must be set harder. On the opposite, when it starts raining tyre grip and lap times go down, in that case a softer setting should be applied.
Lets Get Busy with how to adjust Suspension Setup
Types of Adjustment
On most forks,
Rebound Damping (1) - the screw adjustment at the top is rebound damping (not to be confused with the larger spring preload adjuster)
Preload adjuster (3)- Is the larger nut on the top of the front forks (not to be confused with the smaller rebound damping). Movement of the Forks within the Triple Clamps, can be substituted for the preload adjuster.
Compression Damping (2) - the one on the bottom near the axle is compression damping.

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Rear Shock
Preload adjuster (3&4) - Is adjusted by using a C-Spanner or the appropriate wrench/spanner.
Compression Damping (2) - is the adjuster on the reservoir usually a knob or a screw.
Rebound Damping (1) is the adjuster knob on the shaft .

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On late model shocks it can be located down below the dial #1 near the lower pin but not always.
What is becoming more common these days is low and high speed adjusters for dampning, so this diagram is out of date in this case...
Spring Preload - Release the ring nut (4) by means of the appropriate spanner. Adjust (B) through the adjusting ring nut (3) After adjusting, tighten the ring nut (4).
Rebound Damping - Work the ring nut (1) to set shock absorber rebound damping.
Compression Damping - Adjustments are made by turning the knob or, by turning the screw (2) depending on types of models.
Rear Ride Height Adjustment, proceed as follows:
Slightly loosen the lock nut (5) .
Turn the adjuster (6) to change the overall length of the rear suspension shock absorber length (A) (distance between centers).
Hold the adjuster (6) with the appropriate wrench and tighten the lock nut (5) (aprilia 40Nm)
Miscellaneous
Contrary to the fork's controls, rear rebound damping is changed from the bottom of the shock.
Change the shock's compression damping on the reservoir
The fork rebound adjuster, like all the damping controls, screws in for firmer and out for softer.
The compression damping adjuster usually resides on the lower portion of the fork.
Last edited by
Jonno on Fri May 15, 2009 8:32 am, edited 9 times in total.