Chassis attitude and pitch become a real problem, with the front end refusing to stabilize after the bike is counter steered hard into a turn. Symptoms: Forks are plush, but increasing speed causes loss of control and traction The motorcycle wallows and tends to run wide 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. The ride is quite harsh—just the opposite of the plush feel of too little rebound. The harsh, unforgiving ride makes the bike hard to control when riding through dips and rolling bumps at speed.
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. Front end dive while on the brakes becomes excessive. The front end has a mushy and semi-vague feeling—similar to lack of rebound damping.
The ride is overly harsh, especially at the point when bumps and ripples are contacted by the front wheel. Brake dive is reduced drastically, though the chassis is upset significantly by bumps encountered during braking. Symptom: Front end rides high through the corners, causing the bike to steer wide. It should maintain the pre-determined sag, which will allow the steering geometry to remain constant.
Symptom: Front end chatters or shakes entering turns. Solution: First, verify that oil height is correct. Symptom: Bumps and ripples are felt directly in the triple clamps and through the chassis. This causes the front wheel to bounce over bumps. The ride is plush at cruising speeds, but as the pace increases, the chassis begins to wallow and weave through bumpy corners. This causes poor traction over bumps under hard acceleration; the rear tire starts to chatter due to a lack of wheel control.
There is excessive chassis pitch through large bumps and dips at speed and the rear end rebounds too quickly, upsetting the chassis with a pogo-stick action. 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.
This creates an uneven ride. Traction is poor over bumps during hard acceleration due to lack of suspension compliance. The rear end wants to hop and skip when the throttle is chopped during aggressive corner entries. Symptoms: Ride is harsh, suspension control is limited and traction is lost. Rear end will pack in, 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 to keep rear end from packing. Hitting bumps at speed causes the rear to bottom out, which upsets the chassis.
The chassis attitude is affected too much by large dips and G-outs. Steering and control become difficult due to excessive suspension movement. 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. The ride is harsh, though not quite as bad as too much rebound; the faster you go, the worse it gets, however.
Harshness hurts rear tire traction over bumps, especially during deceleration. Medium to large bumps are felt directly through the chassis; when hit at speed, the rear end kicks up. 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. Tire will overheat. Rear end will want to kick when going over medium to large bumps. Solution: Decrease compression until harshness is gone. Decrease compression until sliding stops and traction is regained. Too hard spring ratio: — Gives easy turning into corners. Too soft spring ratio: — Gives good traction in acceleration. Too hard spring ratio: — Good under braking. Too soft spring ratio: — Gives easy turning into corners.
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 effects 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.
The factories plan on designing a bike that works moderately well for a large section of riders and usages. To accomplish this as economically as possible, manufacturers install valving with very small venturis. These are then matched to a very basic shim stack which creates a damping curve for the given suspension component.
At slower speeds this design can work moderately well, but at higher speeds, when the suspension must react more quickly, the suspension will not flow enough oil, and will experience hydraulic lock.
The solution is to re-valve the active components to gain a proper damping curve. It does not matter what components you have, Ohlins, Fox, KYB, Showa , matching them to your intended use and weight will vastly improve their action. Furthermore, if you can achieve the damping curve that is needed, it does not matter what brand name is on the component. Often with stock components, when you turn the adjusters full in or out, you do not notice a difference.
In part, this is due to the fact that the manufacturer has put the damping curve in an area outside of your ideal range. Also, because the valves have such small venturis, the adjuster change makes very little difference. After re-valving, the adjusters will be brought into play, and when you make an adjustment, you will be able to notice that it affects the way the way the fork or shock performs.
Trying to figure out a handling problem can be tricky. Is it the front or rear causing it? And how do I know if rebound or compression damping adjustments will help? Some of these problems occur entering the corner, some of them happen in mid-corner, and others can even cause difficulty exiting a corner.
Then try our suggested solutions to see if they make an improvement. Remember take it one step at a time, take a test ride after each change, and take notes on whether that change made a difference. Problem: A tank slapping bike feels unstable, especially when entering turns.
Cause : If the bike feels this way, then probably there is too much front end weight bias. Hard cornering makes the bike feel loose, almost as if it has a hinge in the middle. Try stiffening up the rebound damping in small steps, and remember to do the front and rear separately, not simultaneously; that way he can readily see if one or the other makes a difference.
If the rebound damping is cranked up to the maximum and the bike still feels soft and wallowy, you may need to rebuild the suspension components.
Cause: The cause is too much front end weight transfer under braking. Try increasing the fork spring preload first, and progressing in small increments until the handling begins to be negatively affected remember to watch the rebound damping when increasing the spring preload.
Other solutions to try—although less effective—are to increase the compression damping in the forks if possible , or to decrease rebound damping in the rear to allow the rear tire to follow the pavement quicker.
Again, watch for adverse handling reactions in other riding situations when test riding. Problem: The bike is uncomfortable and he feels every little bump in the road. Diving into corners during track days, the bike is unstable and jumps around over every little bump and crack in the tarmac. Cause: The rough ride is most likely due to a generally too-stiff setup—with too much compression and rebound damping. Solution : First off, the rebound adjusters as outlined in the setup section, and back the compression adjusters out to no more than the middle of their range.
This will give a starting point to work from, and get rebound damping in the ballpark. Dialing in the rebound more accurately can be accomplished by riding the bike over a rough section of pavement; the suspension should not pack down too stiff , nor should the bike be wallowy like a Cadillac too soft. Riding the bike repeatedly over the same road after making small changes to the damping adjusters is a good way to distinguish between the characteristics and determine a good setting.
Once the rebound is set properly, the compression damping can be fine-tuned according to the setup section. Once again, make small changes between test sessions over the same road to feel and compare the different settings.
Problem: When braking hard approaching a corner, the front fork bottoms out severely, especially over bumps. However, the fork action and overall bike handling is fine everywhere else. Cause : The problem here is the ride height is set up correctly for his riding style, but the fork action is obviously too soft whenever weight is transferred to the front as when hard braking.
The cure here would be to raise the fork tubes in the triple clamps starting in increments of 4mm , which lowers the front end; you could then increase fork spring preload without causing the ride height problems mentioned previously.
If the preload adjuster becomes maxed out during testing and dial-in, a set of heavier rate springs or a larger preload spacer inside the fork may be necessary. Cause : These characteristics could be the result of a squared-off rear tire too much straight-line riding or notchy or too-tight steering head bearings;. Solution : if the bike has a steering damper mounted, it may be adjusted too tight. Suspension-wise, heavy steering is a typical result of having rear ride height set too low, raking out the chassis like a chopper.
Front and rear sag should be checked and set correctly, followed by another ride to check for any changes in handling. If there is little or no change, gradually change the geometry by either raising the fork tubes in the triple clamps or—and has a rear ride-height adjuster—raising the rear of his bike. The steering is a bit heavy, and on uneven sections of pavement the front tire skips over bumps and threatens to fold if pushed too hard.
Cause : The trouble is probably due to a combination of sag and ride height settings that leaves his bike riding high up front. Solution : Having a front tire skip over bumps on the exit of a turn is a sign that the fork is topping out—without enough sack to allow the suspension to sink into depressions in the road. If the problems persist, backing off the front preload will drop the front of the bike a bit, quickening the steering and letting the wheel track over bumps more effectively.
If, however, the fork starts to bottom under braking with the preload backed off, the fork tubes can be raised in the triple clamps to sharpen the steering while keeping the original preload setting. Every activity has its own language. Learning a new skill sometimes feels as if it requires scaling a linguistic learning curve that makes surmounting Mt. Everest seem like a day hike. To the uninitiated—not that any Sport Rider reader could be accused of this—the language of motorcyclists can seem just as daunting.
Bottoming also called bottoming out —when a suspension component reaches the end of its travel under compression. Bottoming is the opposite of topping out. Cartridge Fork—a sophisticated type of fork that forces oil through bending shims mounted to the face of damping pistons contained within the fork body.
The primary advantage of cartridge forks is they are less progressive than damping rod forks. The shims allow damping control at very low suspension speeds while high speeds deflect the shims more—causing less high-speed damping than fixed orifice damping rods. The resulting ride is firmer with less dive under braking while simultaneously lessening the amount of force square-edged bumps transfer to the chassis.
Damping General is viscous friction. It is caused when liquids are forced through some type of restriction. The key thing to remember about damping is that it is dependent on fluid movement. Damping cares about vertical wheel velocity, not bike speed. As the wheel is forced upward by the bump, the compression circuit controls the speed at which the suspension compresses, helping to keep the spring from allowing an excessive amount of travel or bottoming of the suspension.
Damping—viscous friction caused by forcing a fluid through some type of restriction. Damping force is determined by the speed of the fluid movement, not the distance of suspension travel. Damping Rod Fork —a simple type of fork that utilizes a tube with holes in it to create compression and rebound damping, delivering an extremely progressive damping curve.
The faster the wheel moves vertically, the more oil that is shoved through the holes. Typically, damping rod forks have very little low-speed damping and a great deal of high-speed damping. The ride is characterized by excessive fork dive under braking and hydraulic lock when encountering square-edged bumps.
Having either too much or too little sag will affect the geometry of the motorcycle, which impacts its behavior both on road and off road. Especially if you are an ADV or dual sport tourer, adding weight to your motorcycle is going to affect its sag numbers. Large bags, Zega panniers , or other accessories are going to cause the motorcycle to squat more than it normally would.
Setting off on a long road trip with a hefty load? Be sure to check out that sag number with the bike fully loaded before departing. Suspension preload is the science behind finding the correct sag numbers, but it is very simple. By tightening the adjusting collar or external preload adjuster on the shock you will increase the preload force, which will decrease the sag and vice versa. Using preload to set a proper sag number is vital in making your motorcycle handle properly.
Too much preload will cause the motorcycle to ride high in the suspension stroke and push wide in corners, while not enough will likely reduce the amount of travel you are able to work with on the road.
Unfortunately, preload is often used as a Band-Aid to cover up issues with under- or over-sprung fork and shock springs. For example, its common that motorcycles with too light of springs will have a lot of preload to hold the suspension up and achieve proper sag numbers, but the light spring will let the suspension dive and bottom out much too easily.
Likewise, a spring that heavy will force a very small amount of preload to get the right sag measurement, but will have a very harsh ride. Thus, finding the proper spring rate is key. To do so, measure the amount of free sag the bike has in the rear of the bike—a ballpark number will be somewhere between 5 and 10 millimeters.
On the other hand, a lighter spring rate would be recommended if the free sag is more than 10 millimeters—or the recommended amount your manual calls for. These clickers are in charge of controlling the amount of oil that bypasses the internal valving stacks inside your forks and sock. Small clicks can make big results, especially in terms of performance over bumps or harsh terrain.
Your motorcycle has adjustable suspension for a reason. In 6 easy steps you can have your suspension working perfectly and giving you the best ride of your life. Related Posts. January 5th, 2 Comments. December 30th, 1 Comment. December 23rd, 0 Comments. December 16th, 0 Comments.
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