Suspension setup - How to set up your suspension

Most motorcyclists are well aware that the brakes on their motorcycle must be in good condition, and that this is the most important element for safe riding. They are also well aware that the tires are what create the contact with the asphalt and their grip forms the basis for you to stop in time. They also know that the tires are what form the basis for good grip on the asphalt when cornering.

But is it really that simple?

NO, it is not. There is an extremely important factor missing for both safety and stability during hard braking. The same factor is essential when cornering and, for that matter, your comfort.

Correct, the answer is suspension.

On this page we will tell you a little about how to get maximum safety and comfort from the suspension that is on your motorcycle, or that you are planning to install.

It should be said that the guide to the Pitbox setup manual assumes that your suspension is working properly. A front fork should be serviced at least every two years or every 10,000km, whichever comes first. The same applies to your rear shock. If we are talking track racing, the recommendation is 6-10 hours of driving for both.

Basic suspension setup – SAG

The first step in your setup is measuring SAG. SAG or sag if you will is divided into two terms: Static SAG and Rider SAG. Static SAG is the number of millimeters that the bike settles at each end from it, hanging freely and to the bike standing on the ground and supporting its own weight. Rider SAG is the measurement from each end hanging freely, to the bike standing on the ground with the rider, wearing full riding gear and in the riding position. The easiest way is to get a buddy to help keep the balance, however it is important that the buddy neither pushes nor lifts without measuring. Both measurements are made with the bike in a vertical position on a flat surface (roughly in padding)

Note that you first set the static SAG, i.e. without a driver. From here, it is the hardness of the spring(s) that determines the Rider SAG. If you hit a target that is greater than the tolerance, your spring(s) are too soft. Conversely, the spring(s) are too hard if the target is below the tolerance range.

Note, it is EXTREMELY important that you have SUFFICIENT static SAG, it is NOT enough to keep adding preload to get the rider SAG to fit, at the expense of the static SAG. Change the springs instead!

Guide to suspension setup with the Pitbox

F1 and Z1 measurements are taken with the bike hanging freely so that the suspension is fully extended. These measurements are the reference measurements from which the F2/Z2 and F3/Z3 measurements are subtracted to find static and Rider SAG.

F2 and Z2 measurements are taken with the bike standing in a vertical position on the floor. It is important that the bike is pressed down into the suspension twice before taking the measurements.

F3 and Z3 measurements are taken with the driver in full gear, sitting in the riding position on the motorcycle. It is a good idea to have two friends to help. One to measure and one to keep the balance.

Tools you need

1-2 good friends
A measuring tape or folding rule
Paper and pen (to write down the measurements)
Masking tape
A marker
Calculator
C spanner / hook wrench for rear shock absorber
Socket wrench for front fork preload
A cold Six-Pack for the friends ;-)

Detailed description – step by step

Lift the motorcycle off the ground, the wheels should hang freely so that the suspension both front and rear is stretched out. You cannot use a regular front and rear wheel lift, as these do not take the weight of the suspension. Good places to lift are in the head tube with a head tube lift. As well as through the axle to the rear swingarm. Alternatively, you can lift the bike up by the strap, under e.g. the fork bridge or similar.

Mark two reference points on the motorcycle, at the rear one should be on the rear axle and the other via a vertical line up to a suitable fixed point on e.g. the rear frame or seat part. It is important that the line is vertical and not slanted. Make clear markings in both places, e.g. by putting a piece of masking tape on the motorcycle at the places you have designated as fixed points, on the masking tape you can make a clear marking with a marker. At the front you measure (on upside-down front forks) the distance on the exposed inner leg, from the foot of the fork leg, to the rubber dust ring that protects the oil seal. On motorcycles with regular front forks you can measure the distance from the rubber dust ring, up to the underside of the lower fork bridge or similar. You now have reference points F1 (front) and Z1 (rear)

Measure the distance between the two fixed points.

Lower the motorcycle to the ground so that it supports its own weight. Keep it vertical, without using jacks, slowly compress the suspension twice and leave the bike in the same position when the bike returns to the return position.

Static SAG: Measure the distance between the reference points and subtract them from the reference measurements F1 and Z1. The numbers you are left with are your static SAG, called F2 and Z2.

The following applies in front:

Sports and naked bikes: 25-32mm

Enduro and similar 30-40mm

The following applies to the rear:

Sports and naked bikes: 5-15mm

Enduro and similar 10-20mm

If your SAG is outside these ranges, you should adjust your preload (spring preload).

You increase your SAG by loosening the preload/spring preload. On the front fork, the preload adjustment is usually at the top of the fork. On the rear shock, the preload can be a nut that requires a hook wrench (C Spanner), it can also be hydraulic and adjusted via a lever. There are many layouts of this on different front forks and rear shocks. If in doubt, you should check your instruction manual.

Each time you make an adjustment, repeat the process from point 4 of pushing the bike down slowly, twice.

Rider SAG: The driver, fully equipped, should now get up and sit on the bike in the normal riding position. The feet should be on the footrests and the hands should rest in the normal way on the handlebars. Now one helper should help keep the balance, while helper number two now takes the F and Z measurements again. These measurements are called F3 and Z3. Again, these measurements are subtracted from the F1 and Z1 measurements. You now have your Rider SAG.

The following applies in front:

Sports and naked bikes: 35-40mm

Enduro and similar 40-50mm

The following applies to the rear:

Sports and naked bikes: 25-30mm

Enduro and similar 30-40mm

If your Rider Sag measurement is less than the tolerances listed above, your springs are too hard. If the measurement is greater than the tolerances, your springs are too soft.

*Note: If you set the tolerance for your static SAG to the hard side, e.g. 5mm rear and 25mm front, your experience of the bike will be that the bike feels harder and more sporty, really good for brisk riding, e.g. road racing or trackdays. Conversely, if you set your SAG to the soft side, e.g. 15mm rear and 32mm front, you will get better comfort but also a less proactive suspension with more tendency to dive in the front and settle more in the rear. This solution will, in addition to being more comfortable, also be useful for track use in rainy weather.

The optimal SAG on the street will be in the middle of the tolerances, but since suspension is always a compromise, it can be difficult to hit the SAG right in the eye. If your static SAG at the rear is for example 10mm and your Rider Sag is 35mm, you will be able to tighten the spring up on preload and hit 5mm static SAG and about 30mm Rider SAG (theoretically). This is an okay solution, but if the numbers are for example 10 and 40mm, you will not be able to get within the tolerance range on your Rider SAG without compromising the static SAG. When you hit the maximum number of 30mm Rider SAG, your static SAG will theoretically be 0 and if you tighten it up even more, the damper will end up in either the mechanical stop, or in the working area of the top-off spring (if it is a sports damper with a top-off spring). Without a static SAG, the damper will stretch out when you drive through holes in the asphalt and the like. This causes some very annoying mechanical knocks and the comfort is severely compromised. It MUST be a static thing!

The solution in the latter case, where Rider SAGGET eliminates the Static SAG, is therefore a tighter spring.

**Note: All setup assumes that the suspension and link connectors are in good working order. If the links are dry and not sliding properly, it will affect your SAG measurements. The same will be true for defective needle bearings, etc. So always check that all joints are well lubricated and in good working order.

If you often mess with suspension, the perfect partner is the Slacker V4 special tool that we always use in the Pitbox. It is ultra accurate and you can save setups from REALLY many motorcycles directly in the MoTool app which can be connected via Bluetooth

Thanks to Bitubo Race Suspension for lending the image material. As well as inspiration from Race Tech

Thank you for using our guide to the perfect setup.