Motorcycle Suspension: Setting Preload, Rebound, and Compression

Why You Should Set Up Your Suspension

A poorly set suspension ruins any motorcycle's handling. Too stiff, it bounces off imperfections and loses grip. Too soft, it dives under braking and bottoms out over bumps. The factory setting is a compromise for a 75 kg rider — if you're lighter, heavier, or riding two-up, you need to adjust.

The three fundamental parameters are preload, rebound (extension damping), and compression. Preload sets the static sag. Rebound controls the return speed. Compression controls the resistance to compression.

Step 1 — Measure the SAG

SAG (static sag) is the foundation of every suspension setup. Without correct SAG, rebound and compression adjustments are meaningless.

Method Using a Tape Measure and Zip Tie

• Place a zip tie (cable tie) on the shock shaft or fork stanchion
• Static SAG (no rider): push the zip tie down against the seal, then lift the rear of the bike and let it settle gently. Measure the distance between the zip tie and the seal — this is the sag under the bike's weight alone. Aim for 5–10% of total travel.
• Rider SAG: sit on the bike in normal riding position, fully geared up. Have a friend push the zip tie down. Aim for 25–30% of total travel at the rear and 25–33% at the front.

Example: if your shock has 120 mm of travel, rider SAG should be between 30 and 36 mm.

If SAG Is Incorrect

• Too much sag (SAG > 30%) — increase preload
• Not enough sag (SAG < 25%) — decrease preload
• If preload is maxed out and SAG is still too much, the spring is too soft for your weight. You need a stiffer spring, not more preload.

Step 2 — Set Preload

Rear Shock

Most shocks have a stepped collar adjustable with a C-spanner (hook wrench). Turn clockwise to increase preload (less SAG), counter-clockwise to decrease.

On some sport bikes, it's a hand-wheel or hydraulic remote adjuster. Check your manual to identify the system.

Front Forks

• Conventional forks: preload is often adjusted via a hex bolt on top of the tube. One full turn equals a few millimetres of preload.
• Inverted (USD) forks: same principle, but the adjuster may be at the bottom of the outer tube or the top, depending on the brand (Showa, KYB, WP).

Step 3 — Set Rebound

Rebound controls how fast the suspension extends after being compressed. Too fast and the bike bounces uncontrollably. Too slow and the suspension "packs down" over successive bumps, sitting lower and lower.

• Locate the rebound adjuster — usually at the bottom of the shock (red or gold knob) and on top of the fork tube
• Start from fully open (adjuster backed all the way out, counting clicks)
• Tighten by one third of the total click range
• Test: push down hard on the seat and release. The bike should return in one smooth motion without bouncing

Quick test: if the bike bounces several times, you have too little rebound damping. If it rises very slowly and stays low, you have too much.

Step 4 — Set Compression

Compression controls resistance to being compressed. Adjust it last because it depends on preload and rebound being set correctly first.

• Locate the compression adjuster — usually at the top of the shock or at the bottom of the fork tube
• Start from fully open and tighten by one quarter of the total range
• On the road: if the bike bottoms out over bumps, add compression. If it feels harsh and transmits every imperfection, reduce it.

Settings by Riding Style

• Road — Preload for 28–30% SAG, rebound and compression at one third, comfort is the priority
• Track — Preload for 25–27% SAG, rebound and compression firmer (half range), stability at high speed
• Two-up / loaded — Increase rear preload by 3–5 turns, add 2–3 clicks of rear rebound and compression. The front stays mostly unchanged.

Golden rule: only change one parameter at a time and ride 20 km before judging. Feel changes with temperature and road surface.

Write Down Your Settings

Before touching anything, count the clicks on every adjuster in its current position and write them down. You can always return to the baseline if you get lost.

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