In pursuit of speed, the level of sophistication and technology present in the latest two-wheeled machinery has reached unbelievable heights. However, that level of sophistication has brought along a few complications. The handling of today’s superbikes is similar to the best racing superbikes of a decade ago. This has led to so many adjustments of each suspension component, that it confuses every rider.
Sure, spring preload is easy enough to understand, but what the heck is rebound damping? And what does it do with regards to a motorcycle's handling? Should I go toward the stiff end of the spectrum, or the other way? Where do I begin?
Adrenalin Powersport is THE Suspension Specialist for your suspension tuning of your bike.
You want to ride faster & smoother? Let us help you!
With suspension tuning, we set the bike up to rider weight, riding style and conditions.
If it’s seconds around the track or a safer ride on the road we can help. Our suspension workshop is full equipped with the latest up to date suspension technology tools.
After the service of your suspension, we spend a whole day with you on the track, to make absolutely sure it is set up perfectly for both you and your riding style.
Adrenalin Powersport is the Official Technical Backup for Bitubo in Johannesburg, South Africa.
The Bitubo Factory Race Suspension and the Nitron Racing Shocks are available from Adrenalin Powersport - The Official Service & Support Workshop.
Here is your evidence Suspension Tuning works:
A Before and After picture of front tires after the same amount of laps on the same track by the same rider.
Left: Before Suspension Tuning;
Right: After APS Suspension Tuning with Bitubo Technoloy.
The Suspension Tuning did not only improve the Tire Life, it also took 5 seconds off lap times!
Every activity has its own language. Learning a new skill sometimes feels as if it requires scaling a linguistic learning curve. So, to make sure we're both talking suspension, have a look at the terminology below and speed yourself up on the lingo!
Bottoming (also called bottoming out)
When a suspension component reaches the end of its travel under compression. Bottoming is the opposite of topping out.
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.
Controls the initial "bump stroke" of the suspension. 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. Any change to the damping rod system, such as changing the size of the holes or altering the oil viscosity, affects the entire speed range.
Fork Oil Level
The level of oil within the fork as measured when fully compressed without the spring installed. It is used in tuning the amount of air contained inside the fork. Since compressing air makes it act as a spring, raising the oil level leaves less room for air, resulting in a rising rate throughout the fork's travel. Reducing the oil level reduces the force at the bottom, giving a more linear rate.
The amount the bike settles under its own weight. Both streetbikes and race bikes require 0 to 5mm of free sag on the rear. The bike should not top out hard.
Damping to control fast vertical movements of suspension components caused by road characteristics such as square-edged bumps. High-Speed damping is independent of motorcycle speed.
Damping to control slow vertical suspension movements such as those caused by ripples in pavement. (This is also independent of motorcycle speed).
A phenomenon caused by excessive rebound damping. When a series of bumps, such as ripples, are encountered the suspension does not rebound completely between bumps and compresses (packs) further down on each successive bump. This can drastically change steering geometry if packing occurs on only one end of the motorcycle.
The distance a spring is compressed from its free length as it's installed with the suspension fully extended.
A method of adjusting suspension components' preload externally. These can be ramped or threaded.
Material used to adjust a fork's preload internally. Typically, thin-walled aluminum or PVC tubing is used.
The steering neck angle (not the fork angle) relative to vertical, which varies with changes in ride height. For example, the rake angle decreases when the front end compresses or is lowered. Changes in tire diameter can also influence rake by altering the ride height.
Controls the extension of the fork or shock after it compresses over a bump--hence the term "rebound."
Suspension adjustments (raising or lowering the fork or lengthening or shortening the shock) to alter the chassis attitude of the motorcycle.
The amount the front or rear of the bike compresses between fully topped out and fully loaded with a rider (and all of his riding gear) on board in the riding position. Sag can also affect steering geometry. Extra sag on the front end will decrease the effective steering head angle, quickening steering, while too little front sag will slow steering. However, too much front sag combined with too little rear sag could make the bike unstable. How to set your sag
A mechanical device, usually in the form of a coil, that stores energy. When compressed, more energy is stored. Springs are position sensitive, caring only how much they have been compressed, not how quickly (as with damping).
Used inside a shock absorber to create damping when forced through orifices or valving. The fluid is also used for lubrication and should be incompressible.
Occurs when the suspension extends to its limit. A shock with a spring of the proper rate mounted should have just enough force to top out without a rider on board.
The horizontal distance between the front end's point of rotation (i.e. where a line drawn through the steering head would intersect the ground) and the contact patch of the tire. Since trail is dependent on rake, it is a variable dimension that changes proportionally with the variation of rake during suspension action. For example, trail drops off dramatically when the bike reaches full dive under braking, giving a rider more leverage to initiate steering inputs.
Triple Clamp Offset
The distance from the center of the fork tubes to the steering stem center. The greater the offset, the smaller the trail dimension.
The weight of every part of the motorcycle that is between the road and suspension (i.e. wheels, brakes, suspension components below the springs, etc.).
The mechanical hardware that creates damping. Valving is a combination of check valves, holes, ports, shims, springs, etc.