Two interactive lessons on what a setup change actually does to the car. Move a slider and watch the model react, then try the challenge at the end of each.
In a corner, weight moves to the outside tyres. Each axle carries a share of that transfer, set by how stiff it is in roll. A tyre's grip grows less than its load, so the axle that takes more of the transfer has less grip in total, and it lets go first.
The anti-roll bars are how you move that share between the front and the rear without changing the springs.
Set the bars so both ends let go within 0.005 g of each other.
Your car pushes wide in long, fast corners. Which change helps?
A softer front bar moves load transfer to the rear, so the front keeps more grip. A stiffer rear bar does the same job from the other end.
The model: steady-state cornering, a 1300 kg car with 52% of its weight on the front, tyres that lose grip per kilogram as load rises, and load transfer split by roll stiffness only. Real cars add roll-center (geometric) transfer, which Lesson 2 covers. Racing games hide some of this, but the direction of each change carries over.
Lowering moves the body down but leaves the wheel where it is, so the control arms tilt. That moves the instant center of the suspension, and with it the roll center: the point the body rolls about.
Lower too far and the roll center drops toward the ground. The car then rolls more and the handling changes. Roll-center spacers (extended ball joints) put the arm angles back.
Lower the car at least 40 mm and keep the roll center at 40 mm or more.
After lowering 40 mm with no spacer, where did the roll center go?
The arms tilted up toward the wheel, so the lines through them meet lower down. The roll center falls about three times faster than the ride height here.
The model: a generic double-wishbone front corner in front view, not any particular car or game. Lowering is treated as the wheel moving up relative to the body; the spacer lowers the outer ball joint relative to the knuckle.
The full course would cover the rest of the setup sheet with the same kind of live model and a challenge for each:
Founding price when it opens: US$29, once. Join the Sunfish Labs waitlist to hear when it's ready.
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