Courtesy of Ducati
MotoGP riders have a huge team of people to help with setup, as they have to deal with an almost infinite number of adjustments. Notice how almost everyone in this picture is taking notes: You might have to be your own suspension specialist, data technician, crew chief, and tire engineer all rolled into one, which means taking all the notes for those jobs as well.
In the Oct./Nov. issue of Sport Rider, we talked about chassis geometry and how you can make adjustments to change important characteristics of your motorcycle, such as rake, trail, anti-squat, and center of gravity position (“All About Geometry,” Oct./Nov. ’15). In this article, we will explain how you can put that information to use and make changes to your suspension setup for a better-handling and safer ride both on the street and at the track.
We, and many other publications, have published articles about setup and what all the various adjusters on your bike do and where they are located. We will not rehash that here but instead point you to the Suspension Guide, where you will find all the basic information about springs, preload, damping, sag, and so on. Additionally, your owner’s manual is a good resource for the basics, as they pertain to your bike specifically. In this article we will not concentrate on the nuts-and-bolts side of setup but rather the overall approach—what’s important and how all those geometry numbers interact—and present a method for obtaining the perfect setup.
But is there such a thing as the perfect setup? Yes and no. The goal for any chassis setup is that it allows you to concentrate 100 percent on your riding so that you can ride at your best without being held back by the motorcycle. On the street, that means you can ride comfortably all day at the pace you want, paying better attention to the traffic around you for more safety. Trackday riders want to also ride all day, be able to concentrate on their riding skills, and not worry about tearing up a set of tires. Racers need to be able to focus entirely on racecraft and winning the race, rather than being distracted by a handling issue or having to work around a problem. Attain that goal—whatever your element—and you have the perfect setup.
But that setup is only perfect for that rider, at that track or road, in those conditions. Your perfect setup for Mazda Raceway Laguna Seca most likely won’t work very well at Daytona; a setup that is perfect on Angeles Crest Highway in California might not be all that good at Deals Gap. And your perfect setup is not going to be perfect for your buddy who outweighs you by 50 pounds and has a different riding style. Even for you, as your riding skills improve, the setup will have to evolve accordingly. So, while it’s possible to have “the perfect setup,” don’t count on it being perfect for long.
You might have to con some buddies into helping you measure your sag, but the numbers tell a lot about where in the travel your suspension is working, and you must know the sag values to make progress. If you ever go to a suspension specialist looking for help, we guarantee the first question you will be asked is, “What’s your sag?”
Where to Start—Five Easy Rules
1. Have a baseline to work from.
This can be something from your owner’s manual, our own suggested settings we include with our road tests (also available on our website in the suspension guide), or settings from a previous outing. It doesn’t have to be a great setup, but you must choose it deliberately and be able to go back to it at any time.
2. Measure your sag.
Suspension sag—how much travel is used with you sitting on your bike at a stop—is a very useful reference number, as it tells us where in the range of travel we can expect to be operating. Too much sag and you are in danger of using all the travel and bottoming the suspension; too little and you might top out the fork or shock at inopportune times. Look for between 25mm and 30mm of sag at the rear, closer to 30mm on the street and closer to 25mm on the track. Up front, a lot depends on what’s inside your forks as far as springs and top-out springs; don’t worry so much about the specific setting unless a reputable suspension person gave you a number to aim for, but definitely record what your sag is for reference.
Zip-ties on your fork and shock can show you how much travel you are using and if they are in danger of bottoming. This Honda CBR1000RR SP fork has been modified, and the two orange lines represent soft bottom and hard (metal-to-metal) bottom internally.
3. Make one change at a time.
This might seem obvious, but we even catch ourselves breaking this rule and ending up with exactly the consequences you expect: If you make two changes and your bike works better or worse, how do you know what change is responsible? Keeping to a single adjustment with each iteration lets you pinpoint exactly what the change did and whether it was beneficial or not.
4. Take lots of notes.
Every time you ride your bike or make an adjustment, write down the change you made, why you made it, and how it affected your bike’s handling. Not only will this help you undo any changes you make if you get lost, but also you will be able to—for example—return to a setting you know works at a particular track or fix a problem that could creep up again two years from now.
5: Don’t forget about tires.
Your bike’s handling depends on tire choice and condition almost as much as on any setting adjustment you make. What we are concerned with here is consistency: You want to be sure the changes in your bike’s handling that you experience are from the adjustments you make and not from a change in tire compound, pressure, temperature, or even wear. Use tires with the appropriate street/track bias to match where you are riding, and minimize variables by regularly checking pressures, using warmers at the track, and keeping an eye on wear.
Tire wear can tell you a lot about how well your suspension is or isn’t working. Look for an even pattern across the cornering surface, with no obvious tearing or narrow bands of extreme wear. If it doesn’t look right, check with your tire vendor before making suspension adjustments; it might be a pressure, temperature, or compound issue that will need to be sorted first.
In the Oct./Nov. ’15 issue we broke geometry down into three parts: Trail and front-end geometry; anti-squat and rear-end geometry; and center-of-gravity position. To recap, this table outlines the adjustments you can make to affect each property.
Lower rear ride height, raise front ride height, increase rake, or decrease triple clamp offset
Raise rear ride height, lower front ride height, decrease rake, or increase triple clamp offset
Raise rear ride height to increase swingarm angle, fit shorter gearing, or raise the swingarm pivot
Lower rear ride height to decrease swingarm angle, fit taller gearing, or lower the swingarm pivot
Raise center of gravity
Raise front and rear ride height an equal amount
Lower center of gravity
Lower front and rear ride height an equal amount
Move center of gravity forward
Move axle rearward in the swingarm; move rider forward
Move center of gravity rearward
Move axle forward in the swingarm; move rider rearward
Also in the last issue, we briefly touched on dynamic geometry and how rake, trail, anti-squat, and center-of-gravity height change as the bike goes around the track and the chassis moves on the suspension. The takeaway here is that we can make adjustments to change chassis geometry under certain conditions rather than making a static change that affects geometry in all conditions. For example, to increase front ride height you can lower the forks in the triple clamps; this changes the static geometry. Another option though is to increase front preload, a dynamic change which has the same effect in that it raises the front of the motorcycle with any given load. Provided the suspension is not topping out (which is more likely once you do increase front preload), the fork-height change and the preload change will feel almost exactly alike when you ride the bike.
Another example: We can raise the rear of the bike to increase swingarm angle for more anti-squat (a static change), but that also affects rake and trail. If we didn’t want to change that front-end geometry on corner entry, when the rear suspension is close to topped out, we could fit a stiffer rear spring to keep the rear end higher only when it’s deeper in the stroke mid-corner. Anti-squat would be increased, with a smaller effect on rake and trail. Most street and trackday riders will be fine with OEM adjustments and won’t have to resort to swapping springs, but know that it’s an option if you can’t find a compromise that works for your riding.
With your baseline setup duly recorded, how to proceed? Most setup changes are made to correct existing handling problems: ride, address an issue with an adjustment, and repeat. The riding part is just as important as the adjustment part, and the better you can identify and isolate a troublesome issue, the better you will be able to decide how to correct it. For street riders, don’t simply go out and ride and hope for the best: Have a planned, repeatable route that includes the type of roads and riding you want to match your bike to and has fairly consistent conditions, and pick a time that has as little traffic as possible. Ride your route in its entirety the first couple of times you work on setup so that you don’t end up making changes based on just one type of road.
Street or track, ride at a comfortable pace that lets you focus on how your bike is behaving and what characteristics could be improved. That comfortable pace means you won’t be going your quickest, as you will have to split your concentration. On top of that, be sure to leave enough leeway in your attention span so that you don’t sacrifice safety, especially on the street. The conundrum here is that your pace needs to be close to your usual so that your setup suits that speed and not your slower, comfortable pace. Don’t be surprised if you are quite a bit slower the first few times you ride; as you get more experience with the process and the important handling characteristics, the setup side will fade into the background and you will be able to ride closer to your regular speed. Most top-level riders can ride at race pace and still provide significant feedback about the motorcycle after a session, but that ability comes from years of experience.
As you ride your bike then, what are you looking for? You want to pick one or two issues that are either making you uncomfortable or are preventing you from going faster. It might be something that you know could be improved because of experience—for instance, you know your bike should turn quicker because you rode your buddy’s identical bike and his arcs into corners better, or maybe your bike steered quicker when you had different tires on it. Or it may be a comfort issue—your bike loses traction over bumps on corner exits, and you don’t have the confidence to open the throttle as early as you’d like. After your ride, you should be able to pick one characteristic that you’d like to improve.
Courtesy of Kawasaki
One of the most difficult aspects of setting up your bike might be this part. At first, don’t expect to (or try to) ride anywhere close to your usual pace while at the same time focusing on setup and handling issues. At the track, your pace should be comfortable and consistent; you are not out to set a lap record, but still keep an eye on lap times to see how your setup is progressing.
Time to Spin Wrenches
We’ve prepared a handy chart at the end of this story that outlines some common maladies with recommended adjustments to resolve them. Most items in the table list more than one potential fix, and here you must use your best judgment to pick which adjustment to make. If you are just starting out, stick to the easy adjustments like preload or damping adjustments if they are an option; an important part of the process is getting a feel for what adjustments do what, so it’s all good experience. Make the adjustment (remember, just one adjustment at a time) and go for another ride. If your bike works better and the change improved what you expected it to improve, then good work. Maybe try another adjustment in the same direction and see if things improve even more. If handling is not better, however, then go back to what you know and try something else.
How drastic should your changes be? You want to make adjustments such that you will notice a definite difference when you ride your bike again, either good or bad. In terms of ride height, a 4mm change equates to about 1mm of trail on most bikes, and experienced riders will notice a handling effect with that adjustment; newer riders, or those experimenting for the first time, will want to make steps of 6mm or even 8mm so that those differences are easily felt and categorized. Note that the same applies to preload and sag: A 4mm change in sag will affect trail by about 1mm through most of the suspension’s travel.
A 2mm change in shock length or spring preload equates to a 4mm change in ride height or sag on most bikes, in turn affecting trail by about 1mm. If your shock has a remote preload adjuster, it’s worth determining how many clicks or turns equal 1mm of actual preload adjustment. This shock has been marked “4cl=1mm” (four clicks equals 1mm).
Up front, remember that lowering the fork tubes in the triple clamps by 1mm will raise ride height by 1mm. Fork preload adjusters typically have a 1mm pitch, making one turn of adjustment equal to 1mm of sag (and effective ride height). Out back, collar-type preload adjusters and shock ride height adjusters are usually also 1mm pitch, but the linkage must be taken into account; a ratio of 2:1 is a good ballpark for most linkages, making a two-turn shock length or preload change equal to 4mm in ride height. On big bikes especially, be wary when making rear ride height adjustments. Even a 4mm change can have a big impact on anti-squat.
A good rule of thumb for damping adjustments is to make changes in increments of one-third the current setting for riders new to setup. For example, if front compression is set to 10 clicks out from full stiff, a change of three clicks should be noticeable. If your rebound adjuster is at two turns out, try steps of between a half and three-quarters of a turn. Experienced riders will want to work in smaller increments, down to single clicks or quarter-turns even.
After each riding session, take a moment to collect your thoughts and write down some notes on your bike’s handling. Consider each aspect as we’ve outlined them in the chart: straight, braking, corner entry, midcorner, corner exit, and over the full course of a lap or your street route. Match the issues you want to address with what adjustments would be required, and decide on one adjustment to make for the next session.
Keep in mind that quite often when you make an adjustment to fix one problem, that exact same adjustment may introduce a new problem that needs addressing. For instance, if you do raise the rear ride height to increase anti-squat as in the earlier example, you have also decreased rake and trail and will have to deal with those consequences—good or bad. With experience comes the knowledge of what change to make to fix a certain problem but with the least impact on the setup as a whole. This is why it’s important to measure and keep track of sag: If you know your sag is at the far end of an acceptable range, you can use that to your advantage when making a change. If you wanted more anti-squat and you know your rear sag is on the high side, as an example, it would make sense to add preload. That would add anti-squat dynamically, and at the same time put sag closer to optimal. Always look at your setup as a whole in this manner, rather than just focusing on each issue as it comes up; chasing problem after problem without looking at the big picture will let you fix all those individual problems, but at the end of the day you might not have made any headway on your overall setup.
As mentioned, once you find a setup that works, don’t count on it working forever. You will have to make constant changes to account for different roads or tracks, conditions, tires, changes to your bike, and even as your riding improves. And if you do find that perfect setup, how do you know it couldn’t be even better? Many riders and race teams are constantly experimenting with settings, even once they’ve found a decent race setup; some go as far as always making a change for every session, regardless of how well the bike is working. Just like your riding, your chassis setup should be constantly evolving, and you should always be on the lookout for ways to make improvements.
Once you’ve made an adjustment, always record the change immediately; you’ll forget if you leave it to the end of the day—guaranteed. Your notes should be elaborate enough to serve two purposes: One, you can go back to any point in time and set your bike up exactly the same. Two, if the same handling issue crops up in the future, you can refer to your notes and see exactly what steps you took to fix the problem the first time. It’s a good idea to go over all the adjusters every few sessions and make sure your notes match and nothing gets changed accidentally.
Harsh ride over bumps; chassis is unstable and flighty
Reduce compression damping to improve compliance
Ride gets increasingly harsh over a series of bumps
Reduce rebound damping to avoid packing
High-frequency wobble or headshake
Increase trail to add stability
Check tires, wheel bearing ,and steering head bearings for wear and adjustment; check wheel balance; add rear low-speed compression or rebound damping to minimize oscillation
Rear tire lifts or skates over pavement
Reduce rear rebound damping to keep rear tire on the ground; lower center of gravity or move center of gravity rearward (but not by changing rear wheel position); increase rear sag
Add front preload, low-speed compression damping or increase fork oil level to improve bottoming resistance; increase front spring rate
Lack of braking feel
Reduce front preload or low-speed compression damping to increase load transfer to front tire; decrease fork oil level; decrease front spring rate
Excessive chassis pitch
Lower center of gravity to reduce load transfer; add front low-speed compression damping or rear rebound damping
Front tire locks in reduced traction conditions
Raise center of gravity to increase load transfer
Lack of feel when brakes are released
Increase front rebound damping to prevent fork extending too quickly and unloading front tire
Front tire tucks or turns in too abruptly, especially in slow turns
Increase trail to reduce steering quickness and add stability
Heavy, slow steering
Decrease trail for quicker steering; raise center of gravity
Bike resists turning while brakes are applied
Increase both rake and trail by raising front ride height or lowering rear ride height
Heavy steering in side-to-side transitions
Raise center of gravity
Bike is unstable in side-to-side transitions
Lower center of gravity; add rebound damping and/or reduce low-speed compression damping to keep chassis settled
Ground clearance issues
Raise center of gravity
Lack of compliance or traction feedback
Reduce compression and/or rebound damping; decrease front and/or rear spring rate
Bike is unstable and loose over rough pavement, or wallows over rolling bumps
Increase compression and/or rebound damping
Steering input is required to keep a constant line
If you have to countersteer into the corner (push the bike down) to keep a steady line, reduce trail; if you have to countersteer out of the corner (lift the bike up), add trail
Bike runs wide and resists holding a line
Increase anti-squat to keep load on the front tire; increase rear compression damping or increase rear spring rate to reduce squat; increase front sag
Reduce anti-squat for more load on the rear tire; reduce rear compression damping or reduce rear spring rate for more squat; move center of gravity rearward
Lack of traction feedback or compliance
Reduce rear low-speed compression and/or rebound damping; reduce rear spring rate
Rear suspension pogos during acceleration
Increase rear compression and/or rebound damping
Lower center of gravity; move center of gravity forward
Increase anti-squat; increase spring rate; increase preload