What cross-weight is and why it matters
Cross-weight — also called wedge — is the diagonal balance of the car: the right-front plus left-rear as a share of the total.
cross-weight % = (RF + LR) ÷ total × 100
At 50% the two diagonals are even and the car behaves symmetrically turning left and right — what you want for road and most circuit use. Above 50% adds wedge (more grip in a left turn, less in a right, a trick oval racers use); below 50% does the opposite. You adjust it by raising or lowering spring perch height at one corner, which shifts load diagonally.
Corner balancing is done with the driver's weight aboard (or ballast for it), a full-ish tank set how you'll run it, and ride heights already set. Move one corner and the diagonal partner changes with it, so it's an iterative process — but the target is simple: cross-weight near 50%.
FAQ
What's a good cross-weight percentage?
For a road or road-course car, as close to 50.0% as you can get, so it handles the same in left and right corners. Oval cars deliberately run more than 50% because they only turn one way.
Should I sit in the car when corner balancing?
Yes — the driver's weight (or ballast equal to it) must be aboard, because it changes the corner loads significantly. Set fuel to your typical running level and final ride heights first.
How do I change cross-weight?
Adjust spring-perch (or coilover) height at a corner. Raising a corner adds load to it and its diagonal partner and removes load from the other diagonal, shifting the cross-weight. Re-measure after each change.