Motorcycle Suspension, How They Work, Install and Set Up Presenters: Klaus Huenecke and Duane Kerzic of Wilbers USA Time: Place: Audience: Beginner to Advanced Street Riders who want to know more about what suspension tuning can do to improve their experience. 1
This is a work in progress We can t tell you that this presentation will ever be totally complete. Every time we give it we will update and change it. When we present it we learn more about what people want to know about suspension and will strive to meet those demands. Thanks for understanding. 2
Thanks to all who attended We wanted to thank all of you that came to see us at the BMWMOA Rally 2006. We enjoyed presenting to you and will continue to do so in the future. We wanted to also thank those of you that provided feedback, it was most valuable. This was the first time we gave the presentation so thanks for bearing with some of our mistakes and miscues. Hope to see you all again in the coming years. 3
Agenda Introduction, Overview & Agenda 3:00 Sag Adjustment 5:00 Low-Speed Damping Adjustment 4:00 High-Speed Damping Adjustment 4:00 Rebound Damping Adjustment 4:00 Ride Height 3:00 Summary 2:00 Q&A Session 4:00 Total Time 30:00 4
Introduction How can I tell whether my current shock is bad? What type of shock should I select for the riding I do? How does a shock operate, and what do certain adjustments result in? Adjustments for my personal set-up. Custom Motorcycle Shocks are very adjustable. Increase performance. Improve handling and comfort. Learn to adjust. Sag. High and Low Speed Compression Damping. Rebound Damping. Ride Height. Troubleshooting / Explore when to adjust which setting. 5
Overview This is for street riders. Racers have different needs. There is some transfer. There are many adjustments on a modern shock. They all work together. We want to keep the tire in contact with the road surface and have the least movement of the CG of the bike. We are going to look at the order to adjust the settings, cover them in order and what to do if you don t like what you end up with. 6
How Can I Tell My Shock Is Bad? The bike is lower to the ground then it was previously. Several Causes. You see leakage of fluid from the shock. It s making noises. Pogo stick effect, no damping. Lack of static sag. Broken parts. Changes in handling. Number of miles not always an indicator. 7
How do I Know Which Shock Is For Me? Have you adjusted your current shock? If you have, then you are interested in a better ride. Where and how do I ride? Willing to spend time to fine tune? Different loads? What is your riding style? Track days? Canyon scrape? Do you want to spend the extra money? Bike condition, good swing arm bearings and other suspension parts? 8
Adjusting Your Shock Before You Begin Make Only One Adjustment At A Time. This is important. If you change too much at one time you won t know which adjustment made the change. There are lots of settings. Take your time. If you forgot what you wanted or it doesn t feel right, go back to where you started. Take Notes. This will help you remember what you ve done and where you want to go. If you can use a familiar loop 1-2 miles long (like a track) for testing you ll have an easier time. 9
Sag Adjustment 1 Static and Dynamic Sag. Static sag is the amount of suspension compression when the motorcycle is on the suspension without rider or gear. Dynamic sag is when the motorcycle is loaded with rider and gear. Sag is the first adjustment you make to your shock. Repeated when loading is changed: Gear, Riding Apparel, Passenger. Sometimes called pre-load adjustment. Why do we need to adjust sag? If too much sag suspension will run out of compression (bottom-out) to often, if too little sag will run out of rebound (top-out). Want to be in the middle of the spring travel. Tools: Non-marking tape, tape measure and two buddies. Need to know the suspension travel of your motorcycle from manufacture Specs. 10
Sag Adjustment 2 Pre-load adjuster. This is used to set spring pre-load. This adjusts the sag by changing how much force is applied to the spring. Mechanical Simple. Good if you don t change load often and have no trim panels covering shock. Need to have tool. Hydraulic Very easy to use. Just turn the knob to change setting. Great if you change load often or have trim panels that would need to be removed. No tools needed. 11
Sag Adjustment 3 A is the maximum extension of the shock B is with weight of bike only. C is with all load. A-B = static sag. A-C = dynamic sag. 12
Sag Adjustment 4 To start, we have the motorcycle wheel off the ground and put tape with marks on rear axle and the frame or trim of the bike. This is so we can always measure to the same place and repeat our measurements. This bike still has the factory shock installed. 13
Sag Adjustment 5 Now, measure the distance between the axle and the tape with the suspension fully extended. This is measurement A. A = 530.5mm 14
Sag Adjustment 6 Next we measure the distance between the marks with only the weight of the motorcycle on the rear wheel. B = 517.5mm The Static Sag is A B and should be between 15 and 20 mm for street bikes, 20 and 25 mm for dirt bikes = 530.5 517.5 = 13mm. Wilbers shocks come pre-set for the correct static and dynamic sag based on the load information you give us when you place your order. 15
Sag Adjustment 7 We have the second buddy hold the bike and the rider mounts the bike with his riding apparel on. We measure the distance again. This is measurement C. C = 500 mm The Dynamic Sag is A C = 530.5 500 = 30.5mm Total Travel is 150mm. Dynamic sag should be approximately 1/3 of the total suspension travel or 50mm. Wilbers shocks have spring rates adjusted so you can get the proper Static and Dynamic Sag. 16
Sag Adjustment 8 If there is too little sag we decrease spring pre-load. If there is too much sag we increase spring pre-load. Questions on Sag adjustments? 17
Adjustable Compression Damping All Wilbers shocks have internal damping with shims and ports. The number and size of shims is custom to your shock based on the questions we ask you when you order it. These shims are chosen to give you maximum adjustability. Wilbers offers two types of Adjustable External Compression Dampers; Hose Mounted and Piggy Back. Both reservoirs have a piston to separate the Nitrogen from the shock fluid so the shock only pumps the fluid. Blue adjuster is for Low-Speed and Red is for High-Speed. 18
Low-Speed Damping Low Speed Compression Damping. This is the amount the shock is damped when it is operating at less than 20 inches per second (0.5 m/s) of vertical wheel travel. This is the prevalent damping when you are accelerating, corner turnin and applying the brakes. Effects how the bike sets up for corners. Controls weight transfer. This adjustment isn t for bumps or other road hazards. It s for very slow movements of the suspension. 19
High-Speed Damping High-Speed Compression Damping. This is the damping applied to the shock when it is operating between 1 2/3 (20 ) - 15 feet per second (0.5 4.6 m/s) of vertical wheel travel. This is the prevalent damping for road hazards. Effects how motorcycle reacts to defects in road surface. For example a pothole or bump where there is rapid movement of the suspension. 20
Compression Damping Circuits Questions on Compression Damping? 21
Rebound Damping Soft setting Hard setting This is the damping applied when the shock is rebounding or extending. All Wilbers Shocks have adjustable Rebound Damping in addition to the Internal Shims and Ports. Primarily effects how fast the shock rebounds. The rebound adjuster also effects Compression Damping on emulsion type shocks and to a small degree on shocks with external reservoirs. 22
Rebound Damping Questions on Rebound Damping? 23
Ride Height Adjusts seat height. Changes caster angle and trail of the front suspension. This allows you to change from a bike with fast turn-in (track) to a bike that wants to go straight (tour). Ability to better flat-foot the bike, if you feel the need. About +- adjustment on the seat (total 10mm on the shock) so it is really for fine tuning. Not for major inseam considerations. We offer other solutions. 24
Ride Height Adjustment Questions on Ride Height Adjustment? 25
Permanent Raising and Lowering Wilbers can lower many bikes by up to 2. Some bikes can be raised, but by smaller amounts. Front and rear need to be lowed together. We change the spring rate and damping characteristics of the shock to compensate for the difference in travel and linkage position. We maintain the ride and handling of your bike better then other lowering solutions. We offer advice and support on other changes that need to be made when changing rear suspension travel. We have TUV approval or pending approval on many of these modifications unlike others offering these services. We consider the total feel of the ride. 26
Troubleshooting We are going to cover the following symptoms: Harsh Over Bumps. Excessive Wheel Spin Exiting Corners. Wallowing Exiting Corner. Slow Turn-in. Mid Corner Push Front. 27
Testing Suspension Travel Us wire ties on the shock or fork tubes to show suspension travel. 28
Harsh Over Bumps Go Softer with low speed compression, 2 to 3 clicks at a time. Go softer with high speed compression, 1 to 2 clicks at a time. Increase rear spring sag. Note: Too soft on compression can bring about a harsh feeling by allowing too much shock travel. Riding on the bumper, short of bottoming out. 29
Excessive Wheel Spin Exiting Corners Rear wheel losing push into road. Repeat steps for Harsh over bumps. Rebound can be too fast, allowing the rear to unload and spin the tire. Use caution when changing rebound. 30
Wallowing Exiting Corner Fast yawing movement of bike. Feels like bike has a hinge in the middle and it swings back and forth like a door. Stiffen high speed compression, 1 to 2 clicks at a time. Stiffen low speed compression, 1 to 2 clicks at a time. Decrease rear spring sag. Slow down rebound, 1 to 2 clicks at a time. 31
Slow Turn-in Too much trail. Need to decrease trail at turn entry. Increase rear ride height. Soften fork compression. Increase front fork sag. Speed-up rear rebound. Raise fork legs in triple clamps. This effectively decreases trail. 32
Mid Corner Push - Front Front feels like it s pushing to outside of corner. Need to remove increase in trail as we accelerate through the turn. Stiffen rear low speed compression. Increase front rebound damping. 33
Summary We went over how to tell if your shock was bad. Discussed the different features of a shock and how to figure out what I want / need. We learned the steps for setting up shocks that have Sag, High, Low Speed and Rebound Damping. We covered how these adjustments effect the ride you experience. We learned about some handling deficiencies that can be easily corrected by adjustment of your suspension. It s time to try it on your bike. 34
Where to Get More Information Call us at 732.786.9777 for help with our products. Visit our Website, wilbersusa.com 35
Questions? Anything we didn t cover? Contact us at info@wilbersusa.com. Thanks for your time. 36
Shock Operation 37
Complete Shock 38
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