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Corner Balance Calculator

Car Corner Weight, Wedge and Cross Weight Calculator

By Rob Robinette

This calculator takes your car's four wheel weights and calculates current weights and percentages and generates target wheel weights to achieve a 50% Cross Weight or Wedge. A 50% Cross Weight will yield a balanced handling car, one that turns equally well in both directions. For information on corner balancing see my corner balance how-to and this excellent article: Grassroots Motorsports Understanding Corner Weights

Left Front weight:        Right Front weight:

Left Rear weight:         Right Rear weight: 

 <  Enter your corner weights in pounds or kilos and click 'Calculate'.

These are your current calculated weights:

Total Weight =

                               Front Weight = %

Left Weight = %           Right Weight = %

                               Rear Weight = %

Cross Weight = 50% is optimal

Bite =   Bite should be positive for oval racing

Wedge = %    ∆ Wedge Delta should be positive for oval racing

These are your target weights which will yield a 50% Cross Weight:

Left Front = ∆             Right Front =

Left Rear =              Right Rear =

    ∆ = change needed to get to target weight

Cross Weight =   %  50% is optimal

Bite at 50% will be

Wedge = %   Wedge Delta will be 0 at 50% Wedge

Recommended Reading

You need a nice, flat and level surface for the scales. I highly recommend using a laser level to confirm the 4 scales are level to one another. Even 1/8 inch difference will make a difference, especially if you have stiff springs on your coil overs. I used a laser level to project a horizontal line above each scale and placed a ruler on the top of the scale to take a reading. All 4 scales must be within 1/8 of an inch. I used linoleum tiles to shim two of my scales to get them all level.

Check your tire pressure and bump it up to the hot pressure you run on the track. I use 2x6 wood planks as ramps to drive the car onto the front ramps then jack up the rear and lower it onto the rear scales. It's difficult to position all 4 scales so you can just drive up on all of them at the same time.

Before putting your car on the scales you need to power up the scales and zero them with no weight on them. Also double check that the scales are connected properly--you can really screw up your suspension settings if you have any of the scales connected improperly (i.e. front left and right swapped).

If you don't have adjustable end links on your anti-roll bars then leave them connected. If you do have adjustable end links then disconnect them for the corner balance. Once the corner balance is complete put someone in the driver seat and reconnect the anti-roll bar with the end-link adjusted so it's easy to insert the end-link into the anti-roll bar's hole.

Once you get the car up on the scales you'll need to roll the car back and forth a few inches several times, being careful not to push it off the scales, to unload the suspension (as the car is lowered onto the scales the tires will need to spread out to unbind the suspension). You will have to repeat this every time you lower the car onto the scales.

Note your ride heights and suspension changes to track your progress. When you adjust your coil overs to get the desired corner weights your ride height will change. Always document your current ride heights and your coil over changes each time you weigh and adjust. It's better to make many small changes than to try to balance your car in one big step. You can also estimate your car's center of gravity (CG) height by using this page: CG Height Calculator

Cross Weight = Right Front + Left Rear

Cross Weight % = (Right Front + Left Rear) / (Left Front + Right Rear)

When balanced the Cross Weight % will be 50%

Bite and Wedge Delta are important for oval racers, especially on dirt ovals. Since oval racers only turn left we can balance the car for better grip in left turns. Bite tells us how much we are favoring the left rear tire for better acceleration out of left turns. Bite = Left Rear - Right Rear and a positive value means the Left Rear tire is carrying more weight so it will get more traction and bite, a negative value means the Right Rear is favored.

Wedge is a term used in the oval racing world and is simply another word for Cross Weight. Oval racers discovered they could insert an actual wedge into the left rear springs to put more weight on the left rear (and right front) tires and it would help the car turn left and accelerate better. Today's oval racers add "wedge" by adjusting the right rear spring perch--they retract the right rear tire which puts more weight on the Left Rear and Right Front tires.

When a NASCAR crewchief says he's "adding wedge", what he means is he's adding weight to the left rear and right front tires. To keep things clear I call this added weight Wedge Delta which is simply the difference between the two diagonal tire weights. Wedge Delta can also be thought of as Left Rear Bite + Right Front Bite.

Wedge Delta is equal to (Right Front + Left Rear) - (Left Front + Right Rear) and tells us how much extra weight is on the left rear and right front tires which gives them more traction or bite in left turns. For ovals we want a positive Bite and positive Wedge Delta. When Wedge is balanced at 50% then Wedge Delta will be 0. Of course you can add too much Wedge Delta and make the handling worse. Keeping track of Bite and Wedge Delta and what values work best for certain tracks and conditions can help us get our setup right with less testing. Road racers are typically not concerned with bite and wedge delta because they usually want balanced turning in both directions.

Road racers can take a page out of the oval racing book and intentionally favor a turn direction. If most of the important turns on your track are left turns then having more weight on the Right Front and Left Rear will help with those turns. To favor right turns, put more weight on the Left Front and Right Rear but you'll have to test to find out what works best.

On the Scales

If you prefer Microsoft Excel a Corner Weight spreadsheet is available for download here Corner_Balance.zip

Excel Corner Balance Spreadsheet Screen Capture

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