MTB suspension setup calculator
Build a Better MTB Suspension Setup
Check fork and rear-shock SAG, understand which setting to adjust next, and follow the correct setup order instead of guessing with pressure, rebound and compression.
MTB suspension setup calculator: quick answer
A good mountain bike suspension setup starts with the basics: tire pressure, spring force, SAG and rebound. Compression damping should normally be fine-tuned only after those settings are reasonably close.
Use the calculators below to measure your current fork and rear-shock SAG. Then follow the setup process to decide what to adjust next. For personalized starting values and trail-based fine-tuning, continue your setup in the SAGLY app.
Calculate my SAGMTB fork and rear-shock SAG calculators
SAG is the amount of suspension travel used while you are on the bike in your normal riding position. It is one of the most useful checks when building a suspension baseline.
Fork SAG calculator
Enter your fork travel and the distance the O-ring moved from the dust wiper.
Use the fork’s specified travel, not exposed stanchion length unless the two are identical.
Rear-shock SAG calculator
Enter the shock stroke and measured O-ring movement on the shock shaft.
Use actual shock stroke, not the bike’s rear-wheel travel.
SAG is a starting point, not the complete setup. The correct target depends on the bike, suspension component, riding style and manufacturer recommendation.
What does a complete MTB suspension setup include?
Suspension is a connected system. Changing pressure or spring rate can also change SAG, ride height, travel use and the amount of rebound damping required.
Spring force
Air pressure or coil spring rate establishes the basic support of the fork or rear shock.
SAG
SAG shows where the suspension sits in its travel under normal riding load.
Rebound
Rebound controls how quickly the suspension returns after being compressed.
Low-speed compression
LSC influences support during slower suspension movements such as braking, pumping, berms and rider weight shifts.
High-speed compression
HSC influences resistance during faster damper movements caused by sharper impacts and hard compressions.
Progression
Air-spring volume and compatible volume spacers influence how strongly an air spring ramps up deeper in its travel.
The correct MTB suspension setup order
Avoid tuning several settings at once. Build a repeatable baseline in the correct order so you know which change actually improves the bike.
-
Set tire pressure.
Tire pressure changes grip, harshness and support and can easily be mistaken for a suspension problem. -
Set spring force.
Set fork and rear-shock air pressure or choose an appropriate coil spring rate. -
Measure SAG.
Use your normal riding equipment and repeat the measurement for consistency. -
Set rebound.
Start from the manufacturer’s baseline and record the direction from which clicks are counted. -
Fine-tune compression.
Add or remove damping support only after spring force and rebound are reasonably close. -
Test one change at a time.
Use the same trail section, similar speed and the same line where possible.
For the complete process, read the step-by-step mountain bike suspension setup guide .
More air pressure or more compression damping?
These settings are not interchangeable.
| Setting | Main effect | Check it when |
|---|---|---|
| Air pressure / spring rate | Changes spring support and therefore affects ride height, SAG and the force required to move through the travel. | The bike sits too low or high, SAG is incorrect, or the suspension generally feels too soft or too firm. |
| Low-speed compression | Adds damping support during slower suspension movements. | The bike dives, wallows or lacks support during braking, pumping and cornering despite a sensible spring setup. |
| High-speed compression | Adds damping resistance during faster compression movements. | SAG and spring support are suitable, but hard or sharp impacts still need more control. |
Do not use compression damping to hide an obviously incorrect spring setup. Check pressure, spring rate and SAG first.
How rebound fits into your suspension setup
Rebound controls how quickly the fork or rear shock extends after compression. Because a stronger spring force creates more return force, rebound should be rechecked after meaningful air-pressure or coil-spring changes.
Possible rebound too fast
- Bike kicks after compressions or landings
- Suspension feels bouncy
- Wheel skips across rough ground
- Bike feels unsettled after impacts
Possible rebound too slow
- Suspension packs down through repeated bumps
- Bike rides progressively lower in rough sections
- Suspension starts feeling harsh after several impacts
- Bike feels dead or slow to recover
Read the complete MTB rebound guide for a deeper explanation.
Fork setup vs rear-shock setup
The basic tuning process is similar, but fork and rear-shock pressures should never simply be copied from one another.
MTB fork setup
Identify the exact fork, damper and travel. Set spring pressure, measure SAG, establish rebound and then fine-tune compression and progression.
Complete fork setup guide →Rear-shock setup
Rear-shock setup also depends heavily on frame leverage, shock stroke and the shock tune used for the specific bike.
Complete rear-shock setup guide →MTB suspension troubleshooting
One riding symptom can have several causes. Use these as controlled first checks rather than changing several settings at the same time.
| Symptom | Possible causes | First check |
|---|---|---|
| Suspension feels harsh | Tire pressure, excessive spring force, too much compression, rebound packing or friction. | Check tire pressure and SAG before changing several damper settings. |
| Uses too much travel | Low spring force, excessive SAG, insufficient damping support or insufficient progression. | Verify spring pressure or spring rate and SAG first. |
| Does not use enough travel | High spring force, excessive compression, too much progression or insufficient trail load. | Check actual travel, SAG and the compression baseline. |
| Fork dives heavily under braking | Spring support, excessive SAG, insufficient low-speed support or rider position. | Check fork pressure and SAG before adding large amounts of compression. |
| Bike kicks after impacts | Rebound may be too fast or spring force may be excessive. | Add a small amount of rebound damping and repeat the same feature. |
| Bike gets harsher through repeated bumps | Rebound may be too slow and the suspension may be packing down. | Test slightly faster rebound and repeat the same rough section. |
Continue your MTB suspension setup
MTB suspension setup calculator FAQ
How do I calculate MTB suspension SAG?
Divide the measured suspension movement by the available fork travel or rear-shock stroke and multiply the result by 100. For a rear shock, use shock stroke rather than rear-wheel travel.
How much SAG should an MTB have?
There is no single correct SAG value for every mountain bike. Forks commonly start with less SAG than rear shocks, but the correct target depends on the bike, component, terrain and manufacturer recommendation.
Should I set air pressure or rebound first?
Set spring force and SAG before fine-tuning rebound. A meaningful pressure or spring-rate change can also change the rebound setting that works best.
Should I add PSI or compression if I use too much travel?
Check spring pressure or spring rate and SAG first. If those are appropriate and the suspension still moves too quickly through its travel during particular impacts, compression damping or progression may become the next tuning variable.
Does high-speed compression mean riding at high speed?
No. High-speed compression refers to relatively fast damper movement, not simply the speed of the bike.
Why does my suspension feel harsh even with correct SAG?
Possible causes include tire pressure, compression damping, rebound packing, spring progression, friction or maintenance condition. Test one variable at a time rather than assuming pressure is always the cause.
Can I copy another rider’s suspension settings?
Another rider’s setup can be a reference, but differences in body weight, bike geometry, suspension components, travel, terrain and riding style can require different values.
Does SAGLY calculate suspension settings?
SAGLY helps riders build personalized suspension starting setups, record their settings and fine-tune them based on how the bike feels on the trail.
Go beyond SAG: build your complete suspension setup with SAGLY
The web calculators above help you measure your suspension baseline. SAGLY takes the next step by helping you work with your actual bike, fork and shock settings.
Keep your suspension settings in one place, compare changes and fine-tune the bike based on how it behaves on the trail instead of rebuilding your setup from memory.
Get my suspension setup