Post by Deleted on Mar 6, 2017 16:05:59 GMT 10
Understanding Suspension Basics and Function:
Your bikes suspension is designed primarily to absorb the imperfections in the roads, and ensure that tires keep contact with the road surface. In concert with suspension your tires must be properly inflated and DO NOT SWITCH TIRE COMPOUNDS OR BRANDS and expect your suspension to work correctly.
Most bike suspension is based on a spring that has specific compression values based on machine/rider and gear weight)
In order to prevent the spring from acting like a pogo stick, valving and oil emulsions are used to alter the compression and return forces and everything in between. “DAMPENING”
Dampening allows the fork fluids and spring to respond predictably depending on the size of the hole in the dampening valves or shim stack(s) and the oil viscosity. All bikes have some form of springs and dampers.
Locate your owners manual or tech guide supplied by the manufacturer. The handbook contains details on what can be adjusted and where on the bike via screw or Allen heads and or knobs for setting up your bike front and rear suspension. The manufacturers recommended suspension settings for your bike are very general and often inadequate (most manufactures expect you to be 170 lbs with gear). If you have aftermarket suspension, locate their website for specification and setting recommendations.
Depending on your bike you may be able adjust some, all or none of the following
Preload (Spring tension, based on your weight)
Damping (Speed the spring compresses and returns to normal)
Compression (Advanced damping control, alters the speed the spring compresses)
Rebound (Advanced damping control, alters speed the spring returns to normal after been compressed)
!! Note that compression and rebound are part of damping but have different results !! Every action has an equal or opposite reaction !!
Compare what your current settings are for your bike against the manufacturers setting. If they are different, and you think your bike could handle better, return your setting to manufacturers recommended settings and then begin noting its handling characteristics. You should be able to fiddle with your suspension and bring it back to the settings recommended by the manufacturer or your original setting before you go any further.
!!! DO NOT MAKE MULTIPLE CHANGES - ONE CHANGE AT A TIME !!! ALWAYS START WITH PRELOAD AND PROPERLY INFLATED TIRES !!!
SET UP BIKE TO YOUR WEIGHT(PRELOAD)
To set up your bike you will require the proper tools as recommended in your bikes handbook, usually a long screw driver, spanner wrench for the front and a rear shock spanner tool and tape measure!!. You will need patience. It is best to set the bike up where you are most likely to use it i.e. on the roads or race track. Check all seals, lubricate linkage, and change suspension fluids, check for damage and make sure you have correct tire pressure.
Fiddling about randomly with setting will not result in a better handling bike and in fact may kill you. if set up incorrectly.
!! DO NOT TRY TO MINIC OTHER RIDERS SETTINGS. WHAT WORKS FOR ME LIKELY WONT WORK WELL FOR YOU AND MAY BE DANGEROUS !!
Suspension can be broken down to the following
- Front wheel
Preload
Damping Compression
Damping Rebound
- Rear Wheel
Preload
Damping Compression
Damping Rebound
Ride Height
!! If your bike does not have some of these setting then you will have to compromise on the setting of your bike or buy aftermarket suspension if necessary !!
Rear Preload
Sit on the bike with gear and in a riding position, you want the bike to settle (about 30 - 40 mm). You need to ensure that the bulk of your rear suspension travel is available for when you actually ride the bike and encounter bumps etc.
Measure the fully UNLOADED length of your rear suspension.
Put your bike on its center stand or lifting the rear wheel up under the engine so that there is no weight (including the weight of the bike) on the rear axle and wheel. Measure the distance between the rear axle and a fixed point directly above like a bolt or mark. Note this measure measurement.
!! Do not use a rear wheel bike stand as there is still the weight of the bike on the swing arm!!
Measure the STATIC length of you rear suspension.
This is amount the suspension drops under the weigh of the bike alone without the rider. Put the bike on level ground and bounce it up and down to free any stickiness. Measure between the same two points as above, i.e. the rear axle and the fixed point directly above.
Measure the fully LOADED length of your rear suspension.
This is the length of the suspension with the rear wheel on level ground and the rider seated on it in a normal riding position in full gear.
First bounce up and down on the seat to loosen the suspension then get into your normal riding position with all weight on the bike and both feet on the bike. Have someone hold the bike upright but not affecting load.
STATIC SAG
It is how much the bikes weight acts on the rear suspension or how much you can lift the bike rear without the rider on it before it tops out.
It is how much the bikes weight acts on the rear suspension or how much you can lift the bike rear without the rider on it before it tops out.
RIDER SAG is the difference between Static and Loaded. This is the amount the bike drops when sitting on the bike.
If your rider sag is less than 30 mm then your preload is too firm, if it is more than 40 mm, then it is too bit soft. Once you have set your rider sag as close as possible to 30-40 mm, next check your static sag. If you have more than 10 mm then you need stiffer springs. If however, if your static sag is less than 5 mm or you have no static sag then your springs may be too hard for your weight.
!!If you have to compromise then try to have at least a bit of Static sag in order to stop the bike from topping out!!
Front Preload
Set the front suspension based on rider sag and static sag. This is helpful in determining if you need softer or stiffer springs. Use the same system as above to determine Rider sag
(NOTE: 35-48 mm) and Static sag (25-30 mm). You want your bike to use as much front suspension travel as possible without bottoming out and ideally at 50% travel while neutral riding (no bumps, no cornering forces).
Install a cable tie around the forks near the fork seal. Make sure that it does not scratch the fork tube and it is not too tight as to damage the rubber seals.
With the cable ties in place ride your bike as normal using as many riding conditions (corners, braking, hard braking, accelerating) Then increase or decrease your preload until the cable tie stops about 10 mm before bottoming out.
Reducing preload increases avaialble travel. If the forks bottoms out, reset the cable ties and increase preload until the cable tie stops around 10 mm above the limit for emergencies braking and big pumps or holes to prevent bottoming out.
FRONT DAMPING
The damping, both rebound and compression are best adjusted after riding your bike and feeling how it handles and the fluids are warmed. You have to find your own settings based on “feel” that you are comfortable with and take notes as you experiment with different settings.
Setting the right amount of damping depends on the type of bike, your riding style and shape and pressure of tires. Also it depends on and how much suspension travel you need at any particular moment.
If you can adjust the damping but cannot adjust the rebound and compression separately, then you will have to find a compromise between the two for your bike. If you run out of adjustment, depending on if the damping, rebound or compression is too slow or too fast then you may need to change the damping oil to thinner or thicker weight. (You can mix oils, i.e. 5 wt and 10 wt in ratios to get 13 wt - experiment)
Your suspension will handle differently under different conditions i.e. high or low speed, wet or dry conditions, therefore experiment with setting up your bike under the conditions you will to use it.
Front Compression
You need your front compression under braking and when riding over uneven surfaces.
You want your front suspension to compress slowly and controlled when you break. As your bike dives under braking, it transfers more weight over the front wheel. This helps slow the bike quicker but affects steering.
If the front suspension compresses too quickly (too soft) you risk the suspension bottoming out and then your bike will feel vague and since it nose dives too quickly, the back wheel may loose contact with the road and wander sideways.
The opposite, if compression damping is too high the suspension can't react quickly enough to compress over bumps and will skip and chatter. You will have an uncomfortable ride and your braking and steering is compromised, especially in the wet. Another important aspect of front compression is when you brake just before a turn. As you brake before the corner, the bike will naturally nose dive, this will shorten the wheel base and alter the geometry of the bike making the bike turn quicker into the corner. It is important that your bike compresses predictably and safely in a corner/turn. (ESPECIALLY IF TRAIL BRAKING)
SOFT: If your compression is too soft, your bike will nose dive too quickly, then as you turn into the corner, the bike will collapse into it and you end up having to ride through the issue or tuck the front and lowside.
HARD: Too much front compression damping, do not get enough nose dive and the bike will be reluctant to turn and may drift wide on entry to the corner and drift wider on exit.
Front Rebound
Front rebound damping is to control the rate the bike returns to its preload position after the front suspension has been compressed i.e. from nose down position. If it is too soft, the front end will return too quickly causing the front suspension to compress e.g. braking or cornering causing the bike to rocking horse. This may result in lack of traction If rebound damping is too high you may have lack of “feedback” and in extreme cases where the suspension can't react quickly enough to extend again it will pack down until it bottoms out,
You want your front rebound to work well through corners. As you brake before or trail brake into and partially through the corner, the front suspension compresses, then as you release the brakes, the front wheel will rebound fully. You do not want your front end to return too quickly especially mid corner.
If it rebounds too quickly in the corner your bike will sit up very quickly creating a longer wheel base. This also causes the bike to drift wide or a feeling of the front end washing out. If this occurs, increase (stiffen) your rebound to slow the rate the front wheel rebounds.
If the rebound is too hard, when you release the brakes and roll on the throttle the wheel is compressed resulting in a shorter wheel base. This may cause the bike to feel quick and somewhat unstable. In this instance you need to soften it.
To set up your front rebound damping you are going to have to corner several times the preload and front compression adjusted properly.
1. Brake hard either before the turn or trail brake
2. Release the brakes smoothly
3. Roll on the throttle smoothly
!! Adjust only the rebound damping only at this point !!
NOTES
/NOTES/NOTES:
Keep a record of every adjustment, temperature, tire......... Keep a note of the settings you are using as well as the make and pressure of your tires. Different tires shapes, sizes and pressure.
Counting Clicks/Rotations
If your bike uses clicks or rotations for adjustments
!! DO THEM ONE CLICK OR ROTATION AT A TIME. DO NOT ADJUST MULTIPLE SETTINGS. ONE ADJUSTMENT AT A TIME !!
Altering Bike Geometry/Raising or lowering forks/Adjusting rear ride height
You can alter your bikes geometry by sliding your front forks up or down in the trees or adjusting your rear ride height (if equipped)
.
Raising the fork (More fork exposed at the top of the trees - This makes the bike turn in faster, but the front can tuck and lowside very quickly as well.
Lowering the fork (Less fork exposed at he top of the trees) – This increases your rake making the bike turn in slower. And tends to drift wide.
!! STRONGLY RECOMMENDED: DO NOT ALTER FORK HEIGHT MORE THAN 2 - 5 mm!!
Ride Height - No more than 5 - 10 mm (maybe 15 MAX)
Rear Dampening
This is a rider preference. You want the tire to maintain road contact but not be a pogo stick. The goal is a fluid feeling without wallow or chatter.
Rear Compression
If your rear compression is too hard you will have an uncomfortable, jarring ride because the rear wheel is bouncing over bumps and ripples in the road giving a vague and chattery “feel”. If it is too soft, you will have a wallowy feeling or squatting under heavy acceleration.
When you accelerate, you need a bit of rear end squatting to give the tires a chance to get some traction and absorb excessive power transmitted to the wheel. However, it is that squatting action under heavy acceleration that can cause problems when coming out of corners.
While exiting a corner the bike is leaned over and you start to accelerate aggressively. If the compression damping is too soft, you will get too much rear end “squatting” causing a “nose up” situation. This will cause your bike to drift wide on exit of the corner. This is not the same as a too much front compression damping which causes the bike to drift wide on entry to the corner.
If your rear compression damping is too hard, you will not get enough “squatting” and reduce traction. This may cause rear wheel spin, or the rear wheel suddenly break loose, regain traction and “kick” which is likely going to become a highside.
Rear Rebound
Rebound damping keeps the rear wheel in contact with the road, thereby giving you maximum traction
. Long sweeping corners demand precise rear rebound. If your rear wheel kicks up too quickly, it upsets the chassis becoming a wallow resulting in having to back off the throttle or a light application of rear brake
!! DONT DO THIS IF YOU ARENT PRECISE WITH REAR BRAKING!!
If your rear suspension is too hard, your back wheel will not neutralize. This will cause the back end squatting. This may cause you to drift wide similar to the effects of soft compression. Also since the rear shock does not extend quick enough, you may get a feeling of vagueness or loss of traction which can end in a lowside or a rapid return of traction resulting in a highside.
Suspension Balance
Take the bike off its stand and stand next to it or have a friend hold the bars. Compress the bike rapidly and let go. It should return quickly but not bounce. The front and rear of the bike should move in unison (compress and raise at the same rate). If not adjust rear damping compression and rebound to compensate.
Happy adjusting gents.
DG
Your bikes suspension is designed primarily to absorb the imperfections in the roads, and ensure that tires keep contact with the road surface. In concert with suspension your tires must be properly inflated and DO NOT SWITCH TIRE COMPOUNDS OR BRANDS and expect your suspension to work correctly.
Most bike suspension is based on a spring that has specific compression values based on machine/rider and gear weight)
In order to prevent the spring from acting like a pogo stick, valving and oil emulsions are used to alter the compression and return forces and everything in between. “DAMPENING”
Dampening allows the fork fluids and spring to respond predictably depending on the size of the hole in the dampening valves or shim stack(s) and the oil viscosity. All bikes have some form of springs and dampers.
Locate your owners manual or tech guide supplied by the manufacturer. The handbook contains details on what can be adjusted and where on the bike via screw or Allen heads and or knobs for setting up your bike front and rear suspension. The manufacturers recommended suspension settings for your bike are very general and often inadequate (most manufactures expect you to be 170 lbs with gear). If you have aftermarket suspension, locate their website for specification and setting recommendations.
Depending on your bike you may be able adjust some, all or none of the following
Preload (Spring tension, based on your weight)
Damping (Speed the spring compresses and returns to normal)
Compression (Advanced damping control, alters the speed the spring compresses)
Rebound (Advanced damping control, alters speed the spring returns to normal after been compressed)
!! Note that compression and rebound are part of damping but have different results !! Every action has an equal or opposite reaction !!
Compare what your current settings are for your bike against the manufacturers setting. If they are different, and you think your bike could handle better, return your setting to manufacturers recommended settings and then begin noting its handling characteristics. You should be able to fiddle with your suspension and bring it back to the settings recommended by the manufacturer or your original setting before you go any further.
!!! DO NOT MAKE MULTIPLE CHANGES - ONE CHANGE AT A TIME !!! ALWAYS START WITH PRELOAD AND PROPERLY INFLATED TIRES !!!
SET UP BIKE TO YOUR WEIGHT(PRELOAD)
To set up your bike you will require the proper tools as recommended in your bikes handbook, usually a long screw driver, spanner wrench for the front and a rear shock spanner tool and tape measure!!. You will need patience. It is best to set the bike up where you are most likely to use it i.e. on the roads or race track. Check all seals, lubricate linkage, and change suspension fluids, check for damage and make sure you have correct tire pressure.
Fiddling about randomly with setting will not result in a better handling bike and in fact may kill you. if set up incorrectly.
!! DO NOT TRY TO MINIC OTHER RIDERS SETTINGS. WHAT WORKS FOR ME LIKELY WONT WORK WELL FOR YOU AND MAY BE DANGEROUS !!
Suspension can be broken down to the following
- Front wheel
Preload
Damping Compression
Damping Rebound
- Rear Wheel
Preload
Damping Compression
Damping Rebound
Ride Height
!! If your bike does not have some of these setting then you will have to compromise on the setting of your bike or buy aftermarket suspension if necessary !!
Rear Preload
Sit on the bike with gear and in a riding position, you want the bike to settle (about 30 - 40 mm). You need to ensure that the bulk of your rear suspension travel is available for when you actually ride the bike and encounter bumps etc.
Measure the fully UNLOADED length of your rear suspension.
Put your bike on its center stand or lifting the rear wheel up under the engine so that there is no weight (including the weight of the bike) on the rear axle and wheel. Measure the distance between the rear axle and a fixed point directly above like a bolt or mark. Note this measure measurement.
!! Do not use a rear wheel bike stand as there is still the weight of the bike on the swing arm!!
Measure the STATIC length of you rear suspension.
This is amount the suspension drops under the weigh of the bike alone without the rider. Put the bike on level ground and bounce it up and down to free any stickiness. Measure between the same two points as above, i.e. the rear axle and the fixed point directly above.
Measure the fully LOADED length of your rear suspension.
This is the length of the suspension with the rear wheel on level ground and the rider seated on it in a normal riding position in full gear.
First bounce up and down on the seat to loosen the suspension then get into your normal riding position with all weight on the bike and both feet on the bike. Have someone hold the bike upright but not affecting load.
STATIC SAG
It is how much the bikes weight acts on the rear suspension or how much you can lift the bike rear without the rider on it before it tops out.
It is how much the bikes weight acts on the rear suspension or how much you can lift the bike rear without the rider on it before it tops out.
RIDER SAG is the difference between Static and Loaded. This is the amount the bike drops when sitting on the bike.
If your rider sag is less than 30 mm then your preload is too firm, if it is more than 40 mm, then it is too bit soft. Once you have set your rider sag as close as possible to 30-40 mm, next check your static sag. If you have more than 10 mm then you need stiffer springs. If however, if your static sag is less than 5 mm or you have no static sag then your springs may be too hard for your weight.
!!If you have to compromise then try to have at least a bit of Static sag in order to stop the bike from topping out!!
Front Preload
Set the front suspension based on rider sag and static sag. This is helpful in determining if you need softer or stiffer springs. Use the same system as above to determine Rider sag
(NOTE: 35-48 mm) and Static sag (25-30 mm). You want your bike to use as much front suspension travel as possible without bottoming out and ideally at 50% travel while neutral riding (no bumps, no cornering forces).
Install a cable tie around the forks near the fork seal. Make sure that it does not scratch the fork tube and it is not too tight as to damage the rubber seals.
With the cable ties in place ride your bike as normal using as many riding conditions (corners, braking, hard braking, accelerating) Then increase or decrease your preload until the cable tie stops about 10 mm before bottoming out.
Reducing preload increases avaialble travel. If the forks bottoms out, reset the cable ties and increase preload until the cable tie stops around 10 mm above the limit for emergencies braking and big pumps or holes to prevent bottoming out.
FRONT DAMPING
The damping, both rebound and compression are best adjusted after riding your bike and feeling how it handles and the fluids are warmed. You have to find your own settings based on “feel” that you are comfortable with and take notes as you experiment with different settings.
Setting the right amount of damping depends on the type of bike, your riding style and shape and pressure of tires. Also it depends on and how much suspension travel you need at any particular moment.
If you can adjust the damping but cannot adjust the rebound and compression separately, then you will have to find a compromise between the two for your bike. If you run out of adjustment, depending on if the damping, rebound or compression is too slow or too fast then you may need to change the damping oil to thinner or thicker weight. (You can mix oils, i.e. 5 wt and 10 wt in ratios to get 13 wt - experiment)
Your suspension will handle differently under different conditions i.e. high or low speed, wet or dry conditions, therefore experiment with setting up your bike under the conditions you will to use it.
Front Compression
You need your front compression under braking and when riding over uneven surfaces.
You want your front suspension to compress slowly and controlled when you break. As your bike dives under braking, it transfers more weight over the front wheel. This helps slow the bike quicker but affects steering.
If the front suspension compresses too quickly (too soft) you risk the suspension bottoming out and then your bike will feel vague and since it nose dives too quickly, the back wheel may loose contact with the road and wander sideways.
The opposite, if compression damping is too high the suspension can't react quickly enough to compress over bumps and will skip and chatter. You will have an uncomfortable ride and your braking and steering is compromised, especially in the wet. Another important aspect of front compression is when you brake just before a turn. As you brake before the corner, the bike will naturally nose dive, this will shorten the wheel base and alter the geometry of the bike making the bike turn quicker into the corner. It is important that your bike compresses predictably and safely in a corner/turn. (ESPECIALLY IF TRAIL BRAKING)
SOFT: If your compression is too soft, your bike will nose dive too quickly, then as you turn into the corner, the bike will collapse into it and you end up having to ride through the issue or tuck the front and lowside.
HARD: Too much front compression damping, do not get enough nose dive and the bike will be reluctant to turn and may drift wide on entry to the corner and drift wider on exit.
Front Rebound
Front rebound damping is to control the rate the bike returns to its preload position after the front suspension has been compressed i.e. from nose down position. If it is too soft, the front end will return too quickly causing the front suspension to compress e.g. braking or cornering causing the bike to rocking horse. This may result in lack of traction If rebound damping is too high you may have lack of “feedback” and in extreme cases where the suspension can't react quickly enough to extend again it will pack down until it bottoms out,
You want your front rebound to work well through corners. As you brake before or trail brake into and partially through the corner, the front suspension compresses, then as you release the brakes, the front wheel will rebound fully. You do not want your front end to return too quickly especially mid corner.
If it rebounds too quickly in the corner your bike will sit up very quickly creating a longer wheel base. This also causes the bike to drift wide or a feeling of the front end washing out. If this occurs, increase (stiffen) your rebound to slow the rate the front wheel rebounds.
If the rebound is too hard, when you release the brakes and roll on the throttle the wheel is compressed resulting in a shorter wheel base. This may cause the bike to feel quick and somewhat unstable. In this instance you need to soften it.
To set up your front rebound damping you are going to have to corner several times the preload and front compression adjusted properly.
1. Brake hard either before the turn or trail brake
2. Release the brakes smoothly
3. Roll on the throttle smoothly
!! Adjust only the rebound damping only at this point !!
NOTES
/NOTES/NOTES:
Keep a record of every adjustment, temperature, tire......... Keep a note of the settings you are using as well as the make and pressure of your tires. Different tires shapes, sizes and pressure.
Counting Clicks/Rotations
If your bike uses clicks or rotations for adjustments
!! DO THEM ONE CLICK OR ROTATION AT A TIME. DO NOT ADJUST MULTIPLE SETTINGS. ONE ADJUSTMENT AT A TIME !!
Altering Bike Geometry/Raising or lowering forks/Adjusting rear ride height
You can alter your bikes geometry by sliding your front forks up or down in the trees or adjusting your rear ride height (if equipped)
.
Raising the fork (More fork exposed at the top of the trees - This makes the bike turn in faster, but the front can tuck and lowside very quickly as well.
Lowering the fork (Less fork exposed at he top of the trees) – This increases your rake making the bike turn in slower. And tends to drift wide.
!! STRONGLY RECOMMENDED: DO NOT ALTER FORK HEIGHT MORE THAN 2 - 5 mm!!
Ride Height - No more than 5 - 10 mm (maybe 15 MAX)
Rear Dampening
This is a rider preference. You want the tire to maintain road contact but not be a pogo stick. The goal is a fluid feeling without wallow or chatter.
Rear Compression
If your rear compression is too hard you will have an uncomfortable, jarring ride because the rear wheel is bouncing over bumps and ripples in the road giving a vague and chattery “feel”. If it is too soft, you will have a wallowy feeling or squatting under heavy acceleration.
When you accelerate, you need a bit of rear end squatting to give the tires a chance to get some traction and absorb excessive power transmitted to the wheel. However, it is that squatting action under heavy acceleration that can cause problems when coming out of corners.
While exiting a corner the bike is leaned over and you start to accelerate aggressively. If the compression damping is too soft, you will get too much rear end “squatting” causing a “nose up” situation. This will cause your bike to drift wide on exit of the corner. This is not the same as a too much front compression damping which causes the bike to drift wide on entry to the corner.
If your rear compression damping is too hard, you will not get enough “squatting” and reduce traction. This may cause rear wheel spin, or the rear wheel suddenly break loose, regain traction and “kick” which is likely going to become a highside.
Rear Rebound
Rebound damping keeps the rear wheel in contact with the road, thereby giving you maximum traction
. Long sweeping corners demand precise rear rebound. If your rear wheel kicks up too quickly, it upsets the chassis becoming a wallow resulting in having to back off the throttle or a light application of rear brake
!! DONT DO THIS IF YOU ARENT PRECISE WITH REAR BRAKING!!
If your rear suspension is too hard, your back wheel will not neutralize. This will cause the back end squatting. This may cause you to drift wide similar to the effects of soft compression. Also since the rear shock does not extend quick enough, you may get a feeling of vagueness or loss of traction which can end in a lowside or a rapid return of traction resulting in a highside.
Suspension Balance
Take the bike off its stand and stand next to it or have a friend hold the bars. Compress the bike rapidly and let go. It should return quickly but not bounce. The front and rear of the bike should move in unison (compress and raise at the same rate). If not adjust rear damping compression and rebound to compensate.
Happy adjusting gents.
DG