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Suspension Travel Calculator

2026-09-27 6 min

Wheel travel plus bump/droop split from damper stroke and motion ratio.

Wheel Travel
7.1 in
Bump Travel
3.9 in
~55% of total
Droop Travel
3.2 in
~45% of total

Calculator

Damper Stroke(in) Help
in

Usable shaft travel

Motion Ratio
Results update live as you type

Live statistics

Wheel Travel

7.1 in

Bump Travel

3.9 in

~55% of total

Droop Travel

3.2 in

~45% of total

Results

Optimal

Wheel Travel

7.1in

Bump Travel

3.9in

~55% of total

Droop Travel

3.2in

~45% of total

Planning estimate from standard automotive formulas. Validate with dyno, timeslip or datalog data when precision matters.

Visualizations

Results overview

7.1Wheel Travel
3.9Bump Travel
3.2Droop Travel

Wheel Travel vs. Damper Stroke

Wheel Travel

7.1in
015

Formula

Converts damper catalog stroke into tire travel through leverage, then splits bump vs droop.

Wheel travel = stroke / MR

Alternative Form

Ride-height split ~55% bump / 45% droop for street

Variables

SymbolNameUnitDescription
SStrokeinUsable damper travel

Explanation

Travel decides bottoming and topping: too little bump rides the stops; too little droop lifts tires over crests.

Step-by-Step Calculation

Follow each step to understand how the result is calculated from your inputs.

Step 1

Record the inputs.

Damper Stroke:5 in
Motion Ratio:0.7
Result: 2 inputs ready
Step 2

Apply the formula.

Wheel travel = stroke / MR
Result: Primary result = 7.1 in
Step 3

Read every derived output.

Wheel Travel:7.1 in
Bump Travel:3.9 in
Droop Travel:3.2 in
Result: Wheel Travel = 7.1 in
Final Answer
7.1

Worked Examples

See how the calculator works with different scenarios.

Scenario

Street coilover setup.

Inputs

Stroke:5 in
MR:0.7

Calculation

Travel = 7.1 in (3.9 bump / 3.2 droop)

Result

7.1-in wheel travel.

Interpretation

Healthy street travel — set ride height mid-stroke.

Understanding Your Result

Your Result: Wheel Travel: 7.1 in

What This Means

Tire travel available from the damper stroke.

Why It Matters

Prevents bottoming damage and keeps tires on wavy roads.

Professional Interpretation

Treat the primary result as a planning estimate, then validate on a dyno, at the track, or with logged sensor data. If measured numbers disagree by more than ~10%, re-check inputs (units are the usual culprit) before changing parts.

Recommendations

  • •Double-check units on every input before trusting the result
  • •Compare against the worked example below to sanity-check magnitude
  • •Validate with measured data (dyno, timeslip, datalog) when it matters

Learn — fuel economy, deeply

Stroke is damper travel; wheel travel is what the tire gets.

1 · Where the gallon goes (energy path)

Engine heat

60–70% lost

Coolant + exhaust carry most energy away. Hybrids recover some via Atkinson cycle + regen.

Driveline

5–15% lost

Transmission, differential, accessories. CVTs and 8–10 speed autos lose less.

Aero drag

∝ v²

Doubles from 55→78 mph. Roof boxes hurt more than trunks.

Rolling + brakes

10–20%

Tires, weight, stops. Regen braking (hybrid/EV) reclaims city braking energy.

4 · Measure like a pro (the 3-tank protocol)

  1. Fill to first click at the same pump, record the odometer (Tank 0).
  2. Drive normally for 2–3 tanks; always refill to first click at the same pump.
  3. MPG = total miles ÷ total gallons across all tanks — averaging kills pump-click noise.
  4. Cross-check with the trip computer; a persistent >10% gap means the computer needs calibration — or the car needs service.
  5. Log with an OBD-II dongle for per-trip MPG if you want to isolate commute vs. highway behavior.

Practical Tips

  • •Set ride height for mid-stroke
  • •Keep 1+ in before bump stops
  • •Lowering needs shorter dampers, not preload

Common Mistakes

Mixing units (inches with mm, psi with kPa)
Convert every input to the unit shown on its field before calculating.
Trusting a single output blindly
Cross-check with the worked example and, when it matters, a dyno or datalog.

Assumptions

This calculator makes the following assumptions to provide estimates:

Steady-state model: Formulas assume stabilized conditions; transients, heat soak and traction limits are excluded.
Standard factors: Empirical constants (BSFC, VE, drivetrain loss) use typical values — your combination may differ.

Limitations

Be aware of these limitations when using this calculator:

Estimate, not measurement: Predictions carry real-world scatter of roughly ±5–15% depending on the model.
No transient effects: Shift time, wheelspin, spool lag and heat soak are not modeled here.

Frequently Asked Questions

Answers to common questions about this calculator.

How much suspension travel do I need?
Street 5-7 in wheel travel; track 3-5; rally/off-road 8+. Lowered cars must recover bump with shorter bodies, not just preload.
Bump vs droop?
Bump absorbs hits; droop follows dips. Street ~55/45; track more bump; rally more droop.

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Related Guides

Deepen your understanding with these educational resources.

Glossary

Technical terms used in mortgage calculations explained in plain language.

MPG
Miles per gallon. Distance travelled per gallon of fuel; higher is better. US gallon = 3.785 L.
L/100 km
Litres consumed per 100 kilometres; lower is better. Standard metric efficiency unit.
MPGe
Miles per gallon-equivalent. EV metric: miles travelled on 33.7 kWh (energy of 1 gal of gasoline).
CAFE
Corporate Average Fuel Economy — US fleet-average efficiency standard enforced by NHTSA.
Rolling resistance
Energy lost deforming tires as they roll. Low-pressure or wide tires raise it.
Aerodynamic drag
Air resistance growing with the square of speed — why highway MPG falls fast above 60 mph.
Hypermiling
Driving techniques (coasting, steady speed, anticipation) that maximise real-world MPG.
OBD-II
On-board diagnostics port. Scanners and dongles read live MPG, fuel trim and fault codes.
Droop
Downward wheel travel from ride height — keeps tires planted over crests.

Authoritative References

Trusted sources and standards referenced by this calculator.

Applicable Standards

EPA Fuel Economy Testing (40 CFR Part 600)CAFE — Corporate Average Fuel Economy Standards (NHTSA)WLTP — Worldwide Harmonised Light Vehicle Test ProcedureSAE J1321 / J1711 — Fuel consumption test proceduresISO 2575 — Road vehicles symbols & efficiency markings

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