Guide · 8 min read

Corner balancing and cross weight

The short answer

Corner balancing means weighing each wheel of the car and adjusting the spring perches to share the load evenly across the diagonals. Cross weight is the front-left plus rear-right weight as a percentage of the total. At 50% cross weight, the car handles the same turning left and right; away from 50%, it pushes one way and rotates the other.

  • You can’t change front/rear or left/right totals with adjusters; only moving mass does that. You change the diagonals.
  • 50% cross weight gives the same balance in left and right turns.
  • Weigh the car as it races: driver weight in the seat, typical fuel, correct pressures, level floor.
  • Disconnect or free the anti-roll bars while you adjust, then re-check ride heights.
01

What cross weight is

Put a scale under each wheel and you get four corner weights: front-left, front-right, rear-left and rear-right. Cross weight is the front-left plus the rear-right, divided by the total, written as a percentage. Some people quote the other diagonal instead; what matters is the gap from 50%.

A car is like a four-legged table. If one diagonal carries more load, it’s as if one leg is slightly longer. In a right turn and a left turn the outside tires change, so the loaded diagonal helps in one direction and hurts in the other.

With more weight on the front-left and rear-right diagonal, the car tends to understeer more in left turns and less in right turns, and the reverse for the opposite diagonal.

Weight transfer · load on each tire
Interactive
33%FRONT L33%FRONT R17%REAR L17%REAR RFRONT AXLE 65%REAR AXLE 35%LEFT SIDE 50%
Brake 0.80g
0.00g

1,400 kg car, 0.5 m centre of gravity, 2.6 m wheelbase, 1.55 m track width. More load means more grip, but not proportionally, so pairs of tires lose total grip as load shifts.

02

Why 50% matters

Road courses turn both ways, so most drivers want the car to behave the same in both directions. At 50%, the car brakes straighter and the balance you learn in one corner carries over to the next.

You can’t make every corner weigh the same unless the car’s mass is already perfectly centred. A car with the driver on one side will always be heavier on that side. The goal is the right diagonal split, not identical numbers.

Oval racers set cross weight away from 50% on purpose because they only turn one way. For road courses and track days, aim close to 50% and accept the ride-height trade-offs.

03

How to corner balance

Adjusting a perch moves both the weight and the ride height of that corner. Often the best compromise is a small ride-height difference side to side to get the cross weight near 50%.

  1. 1Use four calibrated scales on a level surface, or level pads under each scale. A floor that’s off by a little can throw the result.
  2. 2Set the car as it runs: correct tire pressures, typical fuel level, and the driver (or equivalent ballast) in the seat.
  3. 3Disconnect at least one end link of each anti-roll bar, or make sure the bars aren’t preloaded, so they don’t hide the result.
  4. 4Roll the car on and off a few times and bounce each corner to settle the suspension before reading.
  5. 5Adjust the spring perches on coilovers in small steps. Raising one corner adds load to it and to its diagonal partner; lowering it does the opposite.
  6. 6Re-check ride heights, re-connect the bars, confirm they aren’t preloaded, and record everything on a setup sheet.
04

Getting help and staying safe

If your car has coilovers, a shop that does corner balancing can set it up and show you the process. Changing ride height also changes alignment, so plan to align after corner balancing, not before.

Support the car on stands, never on a jack alone, when you work under it, and torque every lock ring and fastener to spec before driving.

FAQ

Do I need coilovers to corner balance?

You need a way to adjust each corner’s spring height. Most cars without adjustable perches can only be weighed, not balanced, though moving ballast can still help.

Does corner balancing help a street car?

A stock car is usually close enough. It matters most once you have adjustable suspension and want the same behaviour in left and right turns.

How often should I re-check corner weights?

After any change to springs, ride height, seats or ballast, and after a big off-track moment or kerb strike.

Should I weigh it with me in the car?

Yes, or use ballast of the same weight in the seat. The driver is a big part of the car’s mass and sits off-centre.

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