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Ride Frequency Calculator

Calculate natural ride frequency from spring rate, motion ratio, and sprung mass — or back-calculate the spring rate needed for a target frequency.

Ride frequency (also called natural frequency) describes how quickly the suspension oscillates when displaced. It is the single most important number for characterizing ride quality — how the car feels over bumps, road imperfections, and surface transitions. Lower frequencies (1.0–1.5 Hz) feel softer and more compliant. Higher frequencies (1.8–2.5 Hz) feel stiffer and more responsive. Most street performance cars target 1.0–1.5 Hz front and 1.2–1.7 Hz rear. The rear is typically set slightly higher than the front so that the rear settles before the front when hitting a bump, which prevents a pitching sensation.

While ride frequency is useful for comparing spring setups, it does not tell the full handling story. Handling depends equally on suspension geometry, shock valving, and anti-roll bars — all of which interact with spring rates in ways that ride frequency alone does not capture. It is also worth noting that factory suspension systems are designed with progressive bump stops that act as secondary spring rates deeper in the travel. Many aftermarket coilovers do not rely on bump stops the same way, so directly comparing a factory spring rate to an aftermarket coilover spring rate can be misleading.

These calculators use the linear spring rate and static sprung mass. Real-world frequency will be slightly different due to damping, bushing compliance, and bump stop engagement. The results are accurate enough to compare spring options and dial in a setup target.

Vehicle Parameter Lookup

Select your vehicle to see factory motion ratios and axle weights. Use these as reference values in the calculators below.

About This Data

Axle Weights are factory-published values divided by two to approximate per-corner weight. These do not account for options, modifications, or actual weight distribution. When a calculator requires corner sprung weight, you must subtract your vehicle's unsprung mass from the per-corner value. Unsprung mass includes the wheel, tire, brake assembly, spindle/hub, and portions of the shock absorber and control arms. This data is vehicle-specific and impractical to catalog — for most passenger cars and sports cars, a reasonable estimate is 80–100 lbs (36–45 kg) per corner.

Motion Ratios are sourced from 3DM's own measurements, data shared by reputable engineering partners, or published values from the community. They represent factory suspension geometry and will change with modifications such as lowering, different control arms, or aftermarket shock mounts such as camber plates. Treat these as starting-point references, not absolute values.

Find Ride Frequency

Enter your corner sprung weight, motion ratio, and spring rate to calculate the natural ride frequency and wheel rate for each axle.

Select the units that match your data. Weight and spring rate units are independent — the calculator handles all conversions internally.

Front

Weight supported by one front spring. Front axle weight ÷ 2, minus unsprung mass (~80–100 lbs per corner). The vehicle lookup above shows factory axle weights.
Spring motion ratio for the front axle. This converts the spring rate at the shock into the effective wheel rate that determines ride frequency.
Rate of the front spring as marked on the spring or listed in the product specs. This is the spring rate at the shock, not the wheel rate.
Ride Frequency
Wheel Rate

Rear

Weight supported by one rear spring. Rear axle weight ÷ 2, minus unsprung mass. Rear corners are usually lighter than fronts on front-engine cars.
Spring motion ratio for the rear axle. Often lower than the front — multi-link and double-wishbone rears are typically 0.55–0.80.
Rate of the rear spring. The rear often uses a different rate than the front to achieve the desired frequency split.
Ride Frequency
Wheel Rate

Find Spring Rate from Target Frequency

Working backward — enter your corner sprung weight, motion ratio, and desired ride frequency to calculate the spring rate needed to achieve it.

Select your weight unit. The resulting spring rate is displayed in both N/mm and lbs/in.

Front

Same corner sprung weight as Section 1. Front axle weight ÷ 2, minus unsprung mass.
Front spring motion ratio. The required spring rate is inversely proportional to MR squared — a lower motion ratio requires a stiffer spring to achieve the same frequency.
Desired natural frequency. Street performance: 1.0–1.5 Hz. Track day: 1.5–2.0 Hz. Race: 2.0–3.0+ Hz. Front is typically set slightly lower than rear.
Required Spring Rate
Resulting Wheel Rate

Rear

Rear corner sprung weight. Rear axle weight ÷ 2, minus unsprung mass.
Rear spring motion ratio.
Desired rear frequency. Typically 10–20% higher than the front to prevent pitch oscillation over bumps.
Required Spring Rate
Resulting Wheel Rate
Terminology & Formulas

Natural Ride Frequency — The rate at which the sprung mass oscillates on its springs, measured in Hertz (cycles per second). This is the undamped natural frequency — the damper controls how quickly the oscillation dies out, but does not change the frequency itself.

Wheel Rate — Effective spring rate at the contact patch: wheel_rate = spring_rate × MR². This is what the tire "sees" and what determines ride frequency. A 10 N/mm spring with a 0.7 MR produces a 4.9 N/mm wheel rate.

Spring Rate vs Wheel Rate — Spring rate is the stiffness of the physical spring. Wheel rate is the stiffness felt at the wheel after accounting for motion ratio. Always enter the spring rate (as marked on the spring), not the wheel rate.

Front/Rear Frequency Split — Setting the rear frequency 10–20% higher than the front ensures the rear axle settles before the front after hitting a bump. This produces a flat ride. If the front is higher, the car will pitch nose-up then nose-down over bumps.

Ride Frequency from Spring Rate:

wheel_rate = spring_rate × MR²
frequency (Hz) = (1 / 2π) × √(wheel_rate / sprung_mass)

Spring Rate from Target Frequency:

wheel_rate = sprung_mass × (2π × frequency)²
spring_rate = wheel_rate / MR²
Typical Frequency Ranges
ApplicationFront (Hz)Rear (Hz)
Luxury / comfort0.8 – 1.01.0 – 1.2
OEM sport1.0 – 1.31.2 – 1.5
Street performance1.2 – 1.51.4 – 1.7
Track day / time attack1.5 – 2.01.7 – 2.2
Club racing2.0 – 2.52.2 – 2.8
Pro racing / formula2.5 – 4.0+2.8 – 4.5+