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

Suspension Geometry Calculator

2026-09-27 6 min

Roll moment arm and lateral load transfer per G from weight, CG, roll center and track.

Roll Moment Arm: 16.0 in; CG above roll center
Transfer Per G: 533 lb/g; Lateral load shift per lateral G

Calculator

Axle Weight(lb) Help

Weight on this axle

CG Height(in)

Roll Center Height(in) Help

Axle roll center

Track Width(in)

Results update live as you type

Live statistics

Roll Moment Arm

16.0 in

CG above roll center

Transfer Per G

533 lb/g

Lateral load shift per lateral G

Results

Optimal

Roll Moment Arm

16.0in

CG above roll center

Transfer Per G

533lb/g

Lateral load shift per lateral G

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

Visualizations

Results overview

16Roll Moment Arm

533.3Transfer Per G

Transfer Per G vs. Axle Weight

Transfer Per G

533.3lb/g

02,000

Formula

Roll-moment balance: sprung mass above the roll center levers load across the track.

Transfer/G = axle weight x (CG - RC) / track

Alternative Form

High roll centers reduce roll but add jacking; low centers roll more but stay planted

Variables

Symbol	Name	Unit	Description
h	Moment arm	in	CG minus roll center
T	Track	in	Wider = less transfer

Explanation

Geometry decides how much load moves; springs/bars decide how far the body rolls doing it — separate jobs.

Step-by-Step Calculation

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

Step 1

Record the inputs.

Axle Weight:2000 lb

CG Height:20 in

Roll Center Height:4 in

Track Width:60 in

Result: 4 inputs ready

Step 2

Apply the formula.

Transfer/G = axle weight x (CG - RC) / track

Result: Primary result = 533 lb/g

Step 3

Read every derived output.

Roll Moment Arm:16.0 in

Transfer Per G:533 lb/g

Result: Transfer Per G = 533 lb/g

Final Answer

16.0

Worked Examples

See how the calculator works with different scenarios.

Scenario

Sedan front axle analysis.

Inputs

Weight:2,000 lb

CG:20 in

RC:4 in

Track:60 in

Calculation

Arm = 16 in; transfer = 2,000 x 16/60 = 533 lb/g

Result

533 lb per lateral G.

Interpretation

At 1 g the outside tire gains ~533 lb — size tires and camber curves for it.

Understanding Your Result

Your Result: Roll Moment Arm: 16.0 in

What This Means

Lateral load shift per G from geometry alone.

Why It Matters

Separates geometry effects (arms, links) from spring/bar effects in handling diagnosis.

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

Geometry moves load; springs manage the resulting roll.

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

•Lowering changes roll centers — correct with kits
•Mind RC migration, not just static height
•Balance front/rear transfer distribution

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.

High or low roll center?

Moderate: high RC cuts roll but jacks weight and feels nervous; low RC rolls more but grips. Match front/rear migration.

Why does my car roll if transfer is fixed?

Transfer is geometry-fixed; roll angle is springs/bars resisting it. Both matter, independently.

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.
Roll center: The virtual pivot the sprung mass rolls about — set by link geometry per axle.

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.