rockshox psi calculator

How to use this RockShox PSI calculator

Getting suspension setup right can transform your ride. Too little pressure and the bike wallows, dives, and bottoms out. Too much pressure and it feels harsh, skips over roots, and loses grip. This RockShox PSI calculator helps you find a strong baseline before your first test lap.

The result is not meant to replace RockShox setup charts, but it gives you a reliable number when:

• You changed riding gear weight or body weight
• You switched from mellow trail rides to aggressive descending
• You installed a new fork, rear shock, or air can
• You want to re-center your setup after too many random adjustments

What the calculator considers

1) Rider weight

Weight is the biggest variable for air spring pressure. This tool expects rider weight in full ride kit for the most accurate estimate.

2) Sag target

Sag is how much travel your suspension uses just under rider load. Lower sag generally means higher PSI and a firmer feel. Higher sag generally means lower PSI and more comfort.

3) Component type

Fork and rear shock behave differently. A rear shock also depends on frame leverage ratio, so the same rider can need very different rear PSI across two bikes.

4) Riding style

A race-focused rider often prefers more support and a higher ride height, while a comfort/grip setup usually runs slightly less pressure for compliance.

Good starting sag ranges

• Cross-country fork: 15–20%
• Trail fork: 18–25%
• Enduro fork: 20–25%
• Rear shock trail: 27–32%
• Rear shock enduro: 28–35%

If you are unsure, start near the middle of the range: around 20–22% fork sag and 30% rear sag for all-around trail use.

After you get your PSI result

Step 1: Set pressure accurately

Use a dedicated shock pump. Pressures can change quickly with tiny pump strokes, especially in rear shocks.

Step 2: Cycle suspension

Compress suspension several times to equalize the positive and negative air chambers before checking sag.

Step 3: Re-check sag

Use the o-ring, get into your normal attack position, then step off carefully. Adjust pressure in small increments (2–5 PSI for fork, 5–10 PSI for rear shock).

Step 4: Tune damping

Once spring pressure is correct, set rebound and compression. Spring pressure controls ride height and support, damping controls motion speed and feel.

Common setup mistakes

• Using body weight without gear when you actually ride with pack, water, and tools
• Changing multiple settings at once and losing track of what improved or worsened performance
• Running too little rebound damping after increasing PSI
• Ignoring tire pressure while trying to solve comfort or traction issues in suspension alone
• Overusing tokens to fix poor base pressure and sag

Fork PSI vs rear shock PSI: why they differ so much

Many riders are surprised that rear shock pressure can be dramatically higher than fork pressure. That is normal. Rear shock PSI must account for frame kinematics and leverage ratio. A rider using 85 PSI in the fork might need 190–240 PSI in the rear shock depending on bike design and sag goals.

FAQ

Is this only for RockShox?

It is tuned around common RockShox setup conventions, but the baseline logic can still be useful for similar air-sprung MTB suspension systems.

Do tokens/spacers change PSI?

Mainly they change spring curve progression deeper in travel. Base pressure is still set by sag and support needs. That is why this calculator only applies a small token adjustment.

What if the result is close to max pressure?

Check manufacturer max-pressure limits. If you are near the limit, you may need different tuning hardware, a different air can configuration, or a spring system better matched to your needs.

Final note

Suspension setup is iterative. Use this calculator to get in the zone quickly, then do short test loops and adjust methodically. If you record PSI, sag, rebound clicks, and trail conditions after each ride, your setup improves much faster.