Litres consumed per 100 kilometres; lower is better. Standard metric efficiency unit.

Energy lost deforming tires as they roll. Low-pressure or wide tires raise it.

Automotive Calculators

Ride Frequency Calculator

2026-09-27 6 min

Ride frequency in Hz and cycles/min from wheel rate and sprung corner weight.

Ride Frequency: 1.91 Hz
Cycles Per Minute: 115 cpm

Calculator

Wheel Rate(lb/in)

lb/in

Sprung Corner Weight(lb) Help

Excluding wheel/tire/brake

Results update live as you type

Live statistics

Ride Frequency

1.91 Hz

Cycles Per Minute

115 cpm

Results

Optimal

Ride Frequency

1.91Hz

Cycles Per Minute

115cpm

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

Visualizations

Results overview

1.9Ride Frequency

114.9Cycles Per Minute

Ride Frequency vs. Wheel Rate

Ride Frequency

1.9Hz

Formula

Mass-spring natural frequency in convenient suspension units (386 in/s^2 gravity folded into the constant).

f = 3.127 x sqrt(wheel rate / sprung weight)

Alternative Form

Undamped natural frequency of the corner mass on its spring

Variables

Symbol	Name	Unit	Description
K	Wheel rate	lb/in	At the tire
W	Sprung weight	lb	Corner mass on the spring

Explanation

Frequency is the universal setup language: 1.8 Hz feels stock, 2.5 feels racy, regardless of car weight.

Step-by-Step Calculation

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

Step 1

Record the inputs.

Wheel Rate:300 lb/in

Sprung Corner Weight:800 lb

Result: 2 inputs ready

Step 2

Apply the formula.

f = 3.127 x sqrt(wheel rate / sprung weight)

Result: Primary result = 1.91 Hz

Step 3

Read every derived output.

Ride Frequency:1.91 Hz

Cycles Per Minute:115 cpm

Result: Ride Frequency = 1.91 Hz

Final Answer

1.91

Worked Examples

See how the calculator works with different scenarios.

Scenario

Sport-sedan front axle.

Inputs

Rate:300 lb/in

Weight:800 lb

Calculation

3.127 x sqrt(0.375) = 1.92 Hz (115 cpm)

Result

1.92 Hz.

Interpretation

Enthusiast-street feel; rear target ~2.1 for flat ride.

Understanding Your Result

Your Result: Ride Frequency: 1.91 Hz

Typical range: Luxury 1.0-1.3; stock 1.3-1.6; sport 1.7-2.1; track 2.2-3.0+.

What This Means

How fast the corner oscillates — the feel number.

Why It Matters

Frequencies compare setups across cars; spring rates do not.

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

Frequency is setup feel in universal units.

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)

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

Practical Tips

•Target feel in Hz, buy springs in lb/in
•Keep the flat-ride split
•Aero cars add aero-as-spring at speed

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.

What is flat ride?

Rear frequency ~10-20% above front so both axles settle together over bumps instead of pitching.

Why use sprung (not total) weight?

Unsprung mass (wheels, brakes) does not ride on the spring — including it understates frequency.

Related Calculators

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Related Guides

Deepen your understanding with these educational resources.

Automotive Guides

Build planning, measurement protocol and validation how-tos

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.
Flat ride: Front/rear frequency split (~1:1.1-1.2) that settles pitch after bumps.

Authoritative References

Trusted sources and standards referenced by this calculator.

EPA — FuelEconomy.gov DOE — Fuel-Efficient Driving Tips NHTSA — Driving Safety & Efficiency SAE International — Fuel Economy Standards Consumer Reports — MPG Truth IRS — Standard Mileage Rates

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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Page Information

Last Updated:

2026-09-27

Version:

2.0.0

References:

License:

Free to use for educational and professional purposes.