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SAG
Set PSI and measure real sag in the kit you actually ride in.
MTB suspension calculator
Setup cockpit
Pick the hardware and mass first. The result below shows PSI, SAG and exact dial settings.
Brand
Section
kg
50 kg176 lbs115 kg
kg
How RideLab models mass
80 kg
fork spring mass
80 kg
rear spring mass
0 kg
typical bike
PSI uses part of bike mass, rebound follows rider mass, and LSC/HSC get a separate heavy-bike correction.
Names: fork, rear shock, damper
The fork is the front suspension. The rear shock sits between the frame and linkage. The damper is the oil cartridge controlling rebound and compression inside a fork or shock.
Ride profile
One question: how you actually ride. Sets the SAG target and gently biases compression support.
80 kg
How do you actually ride?
Pick the real riding use, not the bike label. If you don't ride a bike park or race — pick Trail.
How this changes the result
Style sets the SAG target and compression support (±1-2 clicks). Fork PSI and rebound come from the manufacturer tables for your weight — style does not move them. On top of that base RideLab layers bike mass, spacers, skill level, the SAG-measurement correction and symptom diagnostics.
Riding level
Fox 36 FLOAT (2025/2026) · 150mm · GRIP X2 · Trail (regular forest)
Rider: 80 kg (176lbs) · Range: 77-82 kg
Pressure
86 PSI
limit 120 PSI — check SAG
SAG Trail (regular forest)
27.0-33.0 mm
18-22% — Default style: forest singletrack, roots, rocks, short descents. Pick this if you do NOT ride a bike park or race.
Volume Spacers
2 pcs
fabryka 2 · max 7 · Trail: fabryka OK
Fox publishes one PSI table per model — regardless of travel (2025 manual). Changing travel changes the SAG target in mm and spacer count; fine-tune the final PSI with the SAG measurement below.
Step 1 · set SAG before clicks
Fork SAG measurement
Set the real sag in the green target zone first. Rebound and LSC/HSC only make sense after this measurement.
1. Open compression fully — Turn LSC/HSC counter-clockwise to the stop and set the lever to OPEN.
2. Set 86 PSI (table for 80 kg)
3. Wear full riding gear — Helmet, shoes, pack, protection and everything you actually ride with.
4. Slide the o-ring on the stanchion down to the dust seal.
5. Cycle the fork 2-3 times, get into attack position and bounce lightly twice.
6. Dismount carefully without pulling the bike or grabbing the brake.
7. Measure from the seal to the o-ring. That distance is fork SAG in millimeters.
20.0%
30 mm z 150 mm skoku
mm
0 mm27-33 mm (18-22%)44 mm
✓ PERFECT — 20.0% in target 18-22% (Trail (regular forest))
💨 Pump removal pressure loss: fork ~1-2 PSI (large air chamber), rear shock ~3-5 PSI (smaller volume, larger relative loss). If your SAG comes out too firm or too soft after removing the pump, compensate by +2-5 PSI on the next inflation. Quick-release pumps (RockShox Digital, Topeak D2) lose less air.
STEP 2 · MOST IMPORTANT
Note your actual PSI after setting SAG
Table 86 PSI is the table value for 80 kg. Your real PSI after proper SAG may differ by ±10-20 PSI due to frame kinematics, negative-chamber compression, riding style, pump accuracy. This is YOUR number — not the table's.
At 18-22% SAG the pump showed:
PSIRebound — GRIP X2 (turn fully clockwise → back out counter-clockwise)
openclosed
Low-Speed Rebound
middle
Open 7 clicks from closed
1Turn clockwise until closed
2Back out counter-clockwise: 7 / 16
openclosed
High-Speed Rebound
middle
Open 5 clicks from closed
1Turn clockwise until closed
2Back out counter-clockwise: 5 / 8
Engine: Fox table per weight + optional correction from your actual PSI. Style and skill do not move rebound (matches the RationalePanel below).
Compression — GRIP X2
The Fox baseline is a neutral manufacturer start, not an 80 kg table. The result below adjusts compression for style, skill, PSI and bike mass — rebound stays per the weight table.
openclosed
Low-Speed Compression
middle
Open 10 clicks from closed
1Turn clockwise until closed
2Back out counter-clockwise: 10 / 18
openclosed
High-Speed Compression
middle
Open 5 clicks from closed
1Turn clockwise until closed
2Back out counter-clockwise: 5 / 8
After the ride — expand a symptom in the diagnostics below to fix the specific thing. The LSC/HSC cheatsheet and symptom diagnostics are below — no theory duplication.
▸Why this result? 5 channels
Manufacturer rangePhysical base (weight/coil)Algorithm (in range)Algorithm (out of range)
Rebound
7/18 clicks
018
Manufacturer: 6–8in range
- Base from Fox 2025 manual (rider weight) — 7/18 clicks
LSR
7/16 clicks
016
Manufacturer: 6–8in range
- Base from Fox 2025 manual (rider weight) — 7/16 clicks
HSR
5/8 clicks
08
Manufacturer: 4–6in range
- Base from Fox 2025 manual (rider weight) — 5/8 clicks
LSC
10/18 clicks
018
Manufacturer: 8–12in range
- Manufacturer starting point: 10/18 clicks from fully closed (source: Fox 2025 manual)
HSC
5/8 clicks
08
Manufacturer: 3–7in range
- Manufacturer starting point: 5/8 clicks from fully closed (source: Fox 2025 manual)
Pressure table — Fox 36 FLOAT (2025/2026)
| Waga (kg) | Waga (lbs) | PSI |
|---|---|---|
| 54-59 | 120-130 | 66 |
| 59-64 | 130-140 | 70 |
| 64-68 | 140-150 | 74 |
| 68-73 | 150-160 | 78 |
| 73-77 | 160-170 | 82 |
| 77-82 | 170-180 | 86 |
| 82-86 | 180-190 | 89 |
| 86-91 | 190-200 | 94 |
| 91-95 | 200-210 | 99 |
| 95-100 | 210-220 | 105 |
| 100-104 | 220-230 | 109 |
| 104-109 | 230-240 | 113 |
| 109-113 | 240-250 | 117 |
Sources and accuracy
PSI and rebound tables come from official setup guides; style/skill compression modifiers and engine output are RideLab heuristics labeled at each result. Fox 2025 Tech Help Center · RockShox 2025 Front Suspension Specifications and TrailHead · Öhlins owner manuals and product sheets. Where a brand does not publish a universal click table for every bike, RideLab labels the result as a starting heuristic and asks you to confirm sag and the trail symptom.
Post-ride tuning
Shorter decision path
Start with the calculator, then validate on trail. Do not change five things at once: one change, one ride, one conclusion.
2
Rebound
Tune after SAG. It controls whether suspension recovers between repeated hits.
3
Compression
Adjust LSC/HSC for a specific symptom, not rider weight alone.
4
Tokens
Final step: SAG is correct, but the end of travel still feels wrong.
Post-ride diagnosis
Pick the trail symptom. The order of fixes matters.
LSC
Low-Speed Compression
Support for slow shaft movement: braking, berms, pumping and pedaling. If the bike dives or sinks in corners, start here.
HSC
High-Speed Compression
Response to fast impacts: roots, rocks, chatter and landings. Square edges often need more open HSC; landings usually need more support.
Do not do this›
Do not fix rebound with compression
Packing after repeated hits is usually rebound too slow, not too little LSC.
Do not copy random clicks
Setup depends on trail, tires, spacers, service state, riding style and frame kinematics.
Do not hide bad SAG
If SAG is wrong, go back to PSI. Clickers tune behavior; they do not fix the wrong spring.
Fox Factory, SRAM Trailhead, Öhlins setup material, Vorsprung and practical suspension-tuning references.
RideLab setup reference
Pre-ride reference
Quick reference: setup order, SAG ranges by discipline, and answers to common service questions.
1
PSI and SAG
Set pressure first and measure real SAG. For rear shocks, the table is only a starting point because frame kinematics matter.
2
Rebound
Tune after PSI. Too slow packs down in repeated hits; too fast feels bouncy and loses traction.
3
Compression
LSC supports braking, pumping and corners. HSC handles square edges, chatter and landings.
4
Tokens
Adjust only after SAG is correct and the bike still bottoms out or refuses to use full travel.
Typical SAG ranges
| Discipline | Fork | Rear | Who it's for |
|---|---|---|---|
| XC | 15-18% | 20-25% | XC races, marathons, long rides |
| Trail | 18-22% | 25-30% | Regular forest: singletrack, roots, short descents |
| Enduro / All-Mountain | 20-25% | 28-32% | Harder trails, longer descents, drops, enduro racing, lift-assisted |
| DH / Bike park | 15-20% | 30-32% | DH racing, gravity park: full terrain mix — big jumps, rock gardens, braking bumps, roots |
Setup FAQ
Should I copy settings from the internet?›
Not as a final setup. Weight, tires, trail, temperature, spacers, service condition and frame kinematics all change the result.
When should I adjust LSC?›
When the bike dives under braking, sinks in berms, bobs while pumping or lacks mid-stroke support.
When should I adjust HSC?›
When suspension feels harsh on square edges, loses grip in chatter or bottoms on landings despite correct SAG.
SAG is correct but the bike bottoms out. What next?›
Check HSC and landing technique first. If it repeats on the same hits, add a spacer/token instead of masking everything with very firm compression.
Why is shock PSI less reliable than fork PSI?›
The rear shock works through the frame linkage. Leverage ratio, progression and manufacturer tune can move real pressure by tens of PSI.