Suspension Explained


Your motorcycle suspension is designed to keeep in contact with the ground, make for a comfortable ride, allow you to turn a corner as you like and provide forward drive. Many experts will tell you that the single biggest benefit to making a rider go faster is suspension. Get this right, and you will have a ride that is very rewarding. With so many different ranges of adjustment available, many people are not keen to set up their bikes. Hopefully after reading this beginners guide, it may encourage riders to try and learn how to make adjustments and improve the capability that their bikes can provide. Then once understood, settings can be confidently made for the different tracks and terrain that the rider is likely to use.

Before you start

Tyre Pressures
On many MX tracks, set both front and rear tyre pressures to 12psi. MX tracks are generally very similar with a mix of sand, mud, rock and dry clay base. Many tyres also benefit from this pressure so it is easier to have one thing that never changes. If you change your tyre pressures to suit a particular track, you will need to adjust your suspension settings to suit as well. It is far easier to make changes to your suspension only rather than tyre pressure and suspension.

SAG settings
SAG is the beginning of all suspension settings to be performed. Static Sag is used to find of the travel on the bike without a rider on board. Rider/Race sag is the suspension setting for the rider on the sitting in their normal riding position. To set these up, refer to your motorcycle owners manual. Depending on the weight of the rider and their gear, fork and shock suspension springs might have to be changed. If these aren't done before adjustments, the suspension may bottom out or not reach full travel.

Rebound Damping
After the spring has compressed during travel, rebound is how quickly the spring returns back to it's normal state before being compressed. If the rebound is set too fast, the bike may kick up over bumps or when accelerating out of corners. If the rebound is too slow, the suspension may 'pack' meaning the suspension will not return back to it's normal state before hitting the next bump.

High Speed Compression Damping
When hitting a square edged bump, whoops or corrugations will cause the the spring to be compressed very fast.

Low Speed Compression Damping
When hitting a soft round edged bump or landing on the down ramp of a jump, the spring will compress slowly. Low speed compression can also help reduce brake dive and reduce the amount of rear end squat under hard acceleration.

Now the fun begins!!

Make sure the sag settings are correct as per your manual to suit you and your normal riding gear. Using your manual, set all suspension settings to their standard positions. Set the suspension adjustments to what your needs are if there are different types of settings (race or comfort).
Now ride (not race!) the bike around a track that you know well so you can begin to get an understanding of what the bike is actually doing when travelling around the track. Pay attention to what the bike is doing because you can then adjust your suspension to make the bike handle to your technique. In the beginning, this will be a slow process as making adjustments cannot be done while moving.

Jumps
When landing from a jump, does the bike bottom out on it's travel? If yes, adjust for stiffer(more) compression damping. If the bike isn't using the full travel (on big impacts), adjust for less compression damping. If you are unsure of how much travel is used, tie a cable tie around the fork legs and shock absorber and measure the amount used (refer to your manual for travel length). Increase or decrease the compression damping until the suspension uses it's full travel stroke but not bottom hard. While trying to sort out compression, does the bike pogo on rebound (the suspension is accelerating on rebound upwards rather than in control)? If yes, decrease the rebound until the pogo action stops.

Corners
On the track, choose a corner that you know well and feel very comfortable with. When going into the corner, does the bike run wide (understeer) or dip in too quickly (oversteer) at the front or rear. When cornering in a rut and the front tyre tends to climb out, correct it the same way as oversteer.
To correct understeer:
Increase rebound on the forks
Decrease fork compression
Decrease rebound on the shock
Decrease shock compression
To correct oversteer:
Decrease rebound on the forks
Increase fork compression
Increase rebound on the shock
Increase shock compression
Hint If the compression still has the cable tie attached, use this to quickly find out if compression is the one to be adjusted. Generally, adjust rebound first as they will give a very quick indication one the next ride through the corner. If there is too much compression, the ride will be harsh and it will feel like you have been beaten up after going for a ride. Soften the compression so the ride is more compliant to your body!

Bumps Whoops & Holes
Hopefully by following the setups for jumps and corners, the suspsension should now be fairly good and with any luck, only very minor adjustments (one click at a time) will need to be made for bumpy terrain.

Front end deflecting on bumps Fork compression too stiff
Fork rebounding too quickly
Front wheel skipping over bumps Fork compression too soft
Fork rebounding too slowly
Front wheel chatters over small bumps during braking or downhill Fork compression too hard
Rear end kicks up on braking bumps Shock compression too stiff
Shock rebounding too quickly
Rear end oscillates under acceleration Fork compression too soft
Fork rebounding too slowly
Rear end kicks up on jump takeoff Shock compression too stiff
Shock rebounding too quickly

Riding over whoops - note how the rear end feels. If it feels good on the first few bumps and becomes harsh gradually, this could be because the rear end suspension is packing down. Try to speed up the rear rebound two clicks at a time.
If you are going towards full out on clickers and the suspension is still feeling harsh, your problem may not be packing. It could be that your compression is too soft, and you are actually bottoming out. Reset your rebound adjuster back to the standard and start adding more compression, two clicks at a time. Run your test section when adding compression; you should start to feel the bike stay on top of the bumps.