Motorcycle suspension setup can be confusing and downright scary, especially if you hope to figure it out on your own. Or you might wonder: Does it really make a difference in how my bike handles? The answer is, yes, it does.
Suspension is what keeps your wheels in contact with the road, your bike balanced, and your weight distributed in a way that’s optimal for the type of terrain you’re covering, whether it’s silky-smooth tarmac or gnarly off-road. Stock motorcycle suspension is typically set up for an average rider doing average roads, and let’s face it, that person just doesn’t exist. Everyone has a different weight, height, riding skills, the type of riding they do, and so on. Customizing your motorcycle’s suspension to your own needs is the biggest favor you can do to yourself as a rider.
Better yet, adjusting motorcycle suspension isn’t that scary once you know how to do it. Learning about motorcycle suspension tuning is the quickest way to get your motorcycle suspension setup perfectly for you.
How to adjust motorcycle suspension to your weight in 7 quick steps
If you already know what you’re doing and just need a quick reminder of how to adjust motorcycle suspension to your weight, here are the steps:
1. Check that all components are mechanically sound and there are no oil leaks
2. Lift the front wheel off the ground using the center or side stand. Measure the exposed part of the fork leg and write it down in millimeters as L1
3. Position the bike on the ground with the rider in full gear on it. Measure the exposed part of the fork. Write it down as L2
4. Calculate the sag, L1-L2. The sag should be about 1/3 to ¼ of the total suspension travel. Sport rider suspension settings usually have 30mm to 40mm rider sag.
5. Adjust the preload on the forks to achieve the suggested rider sag. More preload = less sag, less preload = more sag.
6. Do the same for the rear. Lift the rear wheel using the center or side stand. Measure between the axle and a distinctive point on the tail. Write it down in mm as L1. Put the rider in full gear on the bike, and measure the same distance to get L2. Your sag follows from L1-L2. Determine the ideal sag for your bike and riding requirements. Adjust the preload on the rear shock.
7. Set your compression and rebound damping for the front and rear.
These steps are easy to do if you’re already familiar with suspension tuning. If you’re just starting out and are hoping for a “motorcycle suspension setup for dummies” guide, fear not – we got you covered!
Motorcycle suspension explanations
Let’s dive into the lingo of suspension adjustment first:
Sag is the distance the suspension compresses from a fully extended, unloaded position. This is the first thing you check and adjust when setting up your suspension. Free sag is the distance the suspension compresses under the weight of the bike alone. Rider sag is where the suspension settles with a fully geared-up rider on the bike.
Preload is how much the spring is compressed from its original length with the suspension component fully extended. Preload alters how much force it takes to initiate suspension motion. More preload makes the bike sit higher. More force will be needed to compress the spring, making it harder for the bike to bottom out. Less preload on the other hand makes the bike sit lower and closer to the bottom of its suspension travel. The main purpose of adjusting the preload is to set sag.
Damping means the reduction of the amplitude of a mechanical oscillation. On a motorcycle, damping regulates the extensions and compression speed of the suspension. When the suspension moves, the oil in the forks and rear shock gets pushed through a small hole or other restriction. The oil’s resistance to flowing through this restriction slows down the suspension motion.
Compression damping determines how fast the suspension can compress when you hit a bump. Rebound damping determines the speed at which the suspension extends after you’ve gone over a bump, to keep the wheels in contact with the road.
Spring rate is the spring’s stiffness in pounds/inches or kilograms/ millimeters. It describes how much force it takes to compress the spring at a given distance. Having the right spring rates for your body weight is important. Springs need to be soft enough to handle bumps, yet stiff enough to prevent bottoming out.
How to set up my motorcycle suspension
Step 1 Check over
Before you start adjusting your motorcycle suspension, make sure all your suspension components are in good nick. Check the seals for leaks and replace them if needed. Lubricate linkage bushings so they move with ease. And, if this hasn’t been done for a while, replace the oil in the forks. You also want to check your steering head bearings and tires. Squared-off tires or notchy steering head bearings will overshadow any improvement your motorcycle suspension tuning attempts will create.
Now, to set up your suspension you will need: the bike, the rider in full riding gear, a friend to do the measurements, pen & paper, tape measure (preferably metric), preload adjustment tool (also called a c-spanner), your bike’s manual, additional spanners, allen keys to adjust the front preload as well as the damping settings, and a wheel chock if you have one.
If you have a wheel chock, you can do this anywhere. Otherwise, position yourself next to a workbench or wall so the rider can hold themselves upright. When measuring, always use the same reference points.
Alternatively, you can use a handy digital sag measuring tool like the Motool to figure out your suspension settings faster.
Step 2 How to adjust motorcycle suspension to your weight – Front forks
This method takes into consideration the drag of the suspension components. This makes it the most accurate way to measure sag in order to set your motorcycle preload.
L1 Lift the front of the bike by leaning the bike onto the side stand or up on the center stand. With the front wheel of the ground, measure the exposed part of the fork. Write down the number in millimeters and call it L1. You measure the part that slides in and out. This is the top part on a traditional fork, or the bottom part on an upside-down fork.
L2 Put the bike on the ground and in the chock. Have the rider with all their riding gear sit on it. Now push down on the front of the bike and let it slowly rise again. Measure the exposed part of the fork again. Write down this measure as L2.
L3 With the bike in the same position, lift up on the front of the bike and let it settle again. Measure the exposed part of the fork and write it down as L3.
Get out your calculator.
Work out the average of L2 and L3. This looks like: (L2+L3)/2. Write it down.
Now take L1 and subtract the average of L2&L3 from it.
Or you can do it in one step by putting it in your calculator like this: L1 – ((L2+L3)/2) = sag
Step 3 Adjusting motorcycle preload on the front forks
If your sag figure is outside of 1/3 to ¼ of total suspension travel (30mm to 40mm for sport rider suspension settings), you should adjust the preload in the front forks. Too much sag, increase the preload. Not enough sag, decrease the preload.
Grab your manual and find out how and where to adjust the preload on the forks. Keep in mind that not all bikes have the option to do this. Write down the changes you make as you go along. Preload adjusted? Determine your new sag figures by repeating the steps above. You might need to give it a few tries to get it perfect.
Step 4 How to adjust motorcycle suspension to your weight – Rear shock
With the front taken care of, you’re ready to start your motorcycle rear shock adjustment.
L1 Lift the rear wheel off the ground. Much like with your front wheel, lean the bike over the side stand or dip it forward on the center stand to lift up the rear wheel. Measure from the rear axle to a distinctive point on the subframe or tail, directly above the axle. This is L1.
L2 Put the bike back on the ground in the wheel chock, or next to your wall or bench. The rider sits on the bike again with their gear on, helmet, boots, gloves, and all. Push down on the back of the bike and allow it to come up slowly. Measure again from the axle to your point on the tail; this is L2.
L3 Then, lift up the rear of the bike. Let it settle down, and measure between the same points to find your L3.
Repeat the calculations you did for the front: L1 – ((L2+L3)/2) = rear rider sag
Ideal figures for rear rider sag range from 25mm to 40mm. They depend on the bike and how you use it. For track riding, you’re aiming around 25mm. Sports bikes on the road perform well with approximately 30mm of rider sag. Consider your bike, riding environment, and style of riding before making changes to the rear shock preload.
Step 5 Adjusting motorcycle preload on the rear shock
Sag figures out? Grab your owner’s manual to find out how to change the preload on the rear shock. This is often done by turning two rings at the top of the rear spring. Like on the front, more preload = less sag, less preload = more sag.
Alternate between measuring and adjusting until you reach the desired sag level.
Can’t get the sag figures in the desired range? If you’re serious about your riding and you want your motorcycle to perform optimally for you, consider changing the springs. Motorcycles roll off the factory belt equipped with springs for the average height and weight rider. If you’re not that, changing your fork springs and/or rear shock spring could make a big difference to the handling of the motorcycle.
How to adjust motorcycle suspension
Once you have set the preload to your weight, you have completed the most tedious part of your motorcycle suspension setup. You’re now ready to adjust the compression and rebound damping. This will determine the level of control, traction, and comfort that you experience while riding.
Step 6 How to adjust suspension damping on a motorcycle
First of all, check your manual to find where and how to adjust these. You’ll likely find that the front fork adjusters are bolts or dials either on top of the fork or at the bottom of the fork leg. The rear shock adjusters are usually at the top or the bottom of the shock unit.
As a general rule of thumb, damping is measured in clicks from the zero position, which is one click out from all the way in. The more you wind the adjusters in, the more damping you’ll have, the slower the suspension moves. This is also referred to as stiff suspension.
You can eye-ball test your rebound damping settings by holding the motorcycle upright, pushing down on it firmly, and observing the movement before it settles to its zero position. Not enough rebound damping results in the suspension shooting up quickly, overshooting the zero position, and all around feeling bouncy before finding the zero position. Too much rebound damping makes the suspension come up very slowly after being compressed.
A good way to start setting your damping is to use the suggested damping adjustments in your manual. Once those are set, ride the bike and pay close attention to how it handles bumps, braking, acceleration, and steering. Write down your experiences, change the settings slightly, and go ride again. Take your time to repeat this process to land on the perfect suspension damping for you.
Riding on the track will require the stiffest suspension setup. The rougher the terrain gets, the softer you want your suspension to enable it to follow the bumps and dips in the road. The weight of the motorcycle should also be taken into account. That is the weight of the rider in full gear, as well as any luggage or passenger.
How to adjust motorcycle suspension for a passenger?
Your weight is one of the main variables in setting up motorcycle suspension. Above we explained how to adjust motorcycle suspension to your weight. When you take a passenger, the weight and weight distribution on the motorcycle change, which might require suspension adjustment.
With the weight of the passenger on the rear, the front is extensively de-loaded upon acceleration, turning the bike into a wheelie-hungry monster. Upon braking, the opposite happens. The increased total weight on the bike quickly compresses the forks further than usual and the bike is ready to catapult your passenger over your head. Ok, we might be exaggerating slightly here, but you get the point. Getting acquainted with how to set up motorcycle suspension for a passenger is the best way to make your ride comfortable and safe again.
The main thing here is to check sag and likely adjust the preload on the rear shock and the front forks.
The process is similar to what is explained above. However, you will need three people this time: a rider, a passenger, and a friend to take the measurements.
1. Lift the front wheel of the ground using the side or center stand, measure the exposed part of the fork leg, and write it down in mm as L1
3. Position the bike on the ground with the rider in all her riding gear, and the passenger fully geared up too. Measure the exposed part of the fork. Write it down as L2
4. Calculate the sag, L1-L2. The sag should again be about 1/3 to ¼ of the total suspension travel.
5. If needed, adjust the preload on the front forks to achieve the suggested rider & passenger sag. More preload = less sag, less preload = more sag.
6. Do the same for your motorcycle rear shock adjustment. Lift the rear wheel using the center or side stand. Measure between the axle and a distinctive point on the tail. Write it down in mm as L1. Get the fully geared up rider and passenger to sit on the bike again, measure the same distance to get L2. Your sag follows from L1-L2. Determine ideal sag for your bike and riding requirements. Adjust the preload on the rear shock.
7. Take the bike for a ride and assess the handling. If you’re not happy with the handling, consider adjusting the compression and rebound damping on the front and rear.
Motorcycle suspension tuning
You made it this far, congratulations! You now know more about motorcycle suspension tuning than most riders. You’re no pro yet, but this knowledge forms the basics on how to set up your suspension yourself. Just keep in mind that adjusting motorcycle suspension to your weight is the first and most important step.
If you’ve now developed a taste for motorcycle suspension tuning, keep playing with it. There is a lot to test and experience, especially in setting the damping. Figuring out how to tune your motorcycle suspension to perfection is also a great excuse to ride more. Go on lots of test rides, take lots of notes, and learn as you go.
We bet that setting and adjusting motorcycle suspension isn’t the black magic you thought it
was! If you’re patient with learning, precise in your measuring, and diligent with your note
taking, you can have your perfect suspension set up dialed in in an afternoon. Following the
steps of measuring sag, adjusting preload, and setting rebound and compression damping,
will become a standard routine for each bike you ride.
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