Enter your sway bar's Arm Length, Outside Diameter, Wall Thickness, and Mid Section Width, then select your Material Type (or plug in a Custom Modulus) to calculate your Sway Bar Rate, along with the Moment of Inertia and whether your bar is classified as solid or hollow.
Sway Bar Rate
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Moment of Inertia
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Bar Type
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Measure from the center of the bar (where it mounts to the chassis) to the center of the end link attachment point. This is typically the distance from the bushing centerline to the drop link hole.
Solid bars are one piece of material throughout, while hollow bars have a tube construction with wall thickness. Hollow bars are lighter but may be less stiff than solid bars of the same outer diameter.
Stiffer sway bars reduce body roll and can help balance understeer/oversteer. A stiffer front bar increases understeer, while a stiffer rear bar increases oversteer. The balance between front and rear rates is crucial.
Steel is most common and cost-effective. Aluminum is lighter but less stiff. Titanium offers high strength-to-weight ratio but is expensive. Most aftermarket bars use high-strength steel alloys.
This calculator provides theoretical spring rates based on beam bending theory. Real-world rates may vary due to mounting compliance, arm stiffness, and manufacturing tolerances. Use manufacturer data when available for precise tuning.
Yes, but you'll need to calculate each adjustment position separately by changing the arm length dimension. Adjustable bars typically have multiple holes at different distances from the center.
Street cars typically use 200-800 lbs/in depending on vehicle weight and suspension design. Race cars often use much stiffer bars, sometimes exceeding 2000 lbs/in, depending on the racing category and track requirements.
This calculator uses inches and pounds. To convert from metric: 1 inch = 25.4mm, 1 lb/in = 175.1 N/m. For wall thickness, 1mm = 0.0394 inches.