Compression and Rebound
Compression is when the spring is compressed under load by either jumping, hitting bumps, braking, accelerating and riding. Rebound is the spring returning back to it's normal state. Inside the forks and shock is oil which helps control (damping) how quickly the spring compresses or rebounds.
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
Used when hitting a square edged bumps, whoops or corrugations will cause the the spring to be compressed very fast. Generally small violent hits to the suspension.
Low Speed Compression Damping
This is mainly with jumps or larger rounded bumps. Reasonably easy on the suspension and not such an impact to the suspension. Low speed compression can also help reduce brake dive and reduce the amount of rear end squat under hard acceleration.
SAG settings
SAG is the starting point of all suspension settings to be performed. Static Sag is the weight of the bike fully fuelled and balanced by itself. Rider or Race sag is when the fully clothed rider is on the bike in their normal riding position. To set these up, refer to your owners manual. These settings can best done at home when you have plenty of time and friends to help you. After completing your SAG settings, from your manual, set all suspension settings to their recommended settings (race or comfort).
| Runs wide in corners Front tyre climbs out of ruts |
Understeer | Increase rebound on the forks Decrease fork compression Decrease rebound on the shock Decrease shock compression |
| Tips into corners | Oversteer | Decrease rebound on the forks Increase fork compression Increase rebound on the shock Increase shock compression |
| Rear wheel pogo'ing/oscillating Rear wheel fish-tailing under acceleration |
Decrease rebound on the shock |
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.
Hint Generally, adjust rebound first as it will give a very quick indication on 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 hard Fork rebounding too fast |
| 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 | Shock compression too soft Shock rebounding too slowly |
| Rear end kicks up on jump takeoff | Shock compression too stiff Shock rebounding too quickly |
When 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 shock is packing down so increase rear rebound two clicks. If you are going towards full out on adjustment 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.
Due to the nature of race tracks, it is impossible to have a suspension setting that works every where around the track. As a racer. you need to decide what suits you most at the track.
Adjusting your suspension can be time consuming but once done, it gives you more confidence making you faster and ultimately, a safer rider.