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Roll centre explained: how to find it on a double-wishbone car

FrameScore guide · updated 23 October 2026

The roll centre is the point the body appears to roll about, seen from the front or rear. On a double-wishbone suspension you find it with two lines from each side: it is set entirely by where you put the wishbone pickup points.

How to find it, step by step

Work in the front view, with the car at ride height:

1. Extend a line through the inner and outer pivots of the upper wishbone, and another through the lower wishbone.
2. Where those two lines meet is that wheel's instant centre: the point the wheel is rotating about at that moment.
3. Draw a line from the instant centre to the centre of the tyre contact patch.
4. Do the same on the other side. On a symmetrical car, the two lines cross on the centreline. That crossing point is the roll centre.

If the wishbones are parallel, the instant centre is at infinity and the line from the contact patch runs parallel to the wishbones. Equal, parallel wishbones put the roll centre at ground level.

Why the height matters

When the car corners, the body's weight acts at the centre of gravity. The distance between the centre of gravity and the roll axis is the roll moment arm: the longer it is, the more the body rolls for the same springs and anti-roll bars.

• A higher roll centre reduces body roll and puts more of the cornering load straight into the wishbones, but it also pushes the body up as the tyres load (called jacking) and makes the car feel less progressive.
• A lower roll centre gives more roll for the same springs, so you need stiffer springs or bars, but it keeps the car settled and predictable.
• The front and rear roll centres together set the roll axis. Their relative heights affect how load transfers front to rear, which changes the balance between understeer and oversteer.

Low race and track cars usually keep their roll centres fairly close to the ground. What matters as much as the height is how much it moves: a roll centre that drops or swings sideways as the car rolls makes the handling change mid-corner.

Common mistakes

• Checking the roll centre only at ride height and never through bump, droop and roll.
• Moving a pickup point to fix camber gain without rechecking the roll centre, which moves with it.
• Using different front and rear geometry without thinking about the roll axis between them.

Related: Bump steer: what it is and how to fix it