Scaling your race car is arguably one of the most critical practices to ensure consistent handling and increase your chances of visiting victory lane. Proper chassis setup requires a precise weight balance customized for your car, driver, and track conditions.
Follow this step-by-step guide to achieve accurate, repeatable results every single week.
🛠️ Pre-Scale Inspection & Setup Checklist
Before placing your car on scale pads, ensure it is fully race-ready. Any unfinished mechanical adjustments will distort your end results.
Fluid Levels: Top off fuel, oil, coolant, and brake fluid.
Tires: Set staggered measurements and exact hot/cold tire pressures.
Chassis Alignment: Adjust ride heights, caster, camber, toe, and verify the rear end is square.
Weight Limits: Check that total weight complies with track rules and maximize your allowable left-side percentage.
Step 1: Prep & Level Your Surface
Garage floors vary widely in level. Taking a few extra minutes here guarantees consistency week to week.
Mark Your Spot: Using a straight edge and level, locate a flat section of floor. Mark four spots matching your car’s wheelbase and track width.
Level the Pads: Use shims or leveling trays to bring all four pads into the exact same plane.
Label Equipment: Mark your shims/trays with LF, RF, LR, RR to quickly replicate your workspace every setup session.
Step 2: Scale Setup & Zeroing
Position pads next to their corresponding tires.
Connect all cables, verifying each lead is plugged into the correct corner pad.
Turn on the control box.
Zero out: Ensure no weight is resting on the pads, then press the ZERO button. Verify the display reads zero before loading the car.
Step 3: Positioning & Settling the Chassis
Load the Car: Jack up one side at a time and slide pads beneath the tires. Place the car in gear or use wheel chocks to prevent rolling.
Disconnect Sway Bar: Ensure the sway bar is either completely disconnected or set neutral with plenty of slop so it doesn't bind or preload the suspension.
Settle the Suspension:
Push down firmly on the rear bumper with your knee to settle the rear.
Repeat the same knee press on the front bumper.
Grab the roof roll bar and shake the car firmly side-to-side, letting go right in the middle.
Why Settle? Settling eliminates suspension bind and prevents shocks from hanging up, ensuring true scale readings. Settle the car every single time you make an adjustment or raise the jack.
Step 4: Measuring & Adjusting Percentages
1. Total & Partial Weights
Record your wheel weights, total weight, and percentage splits (Left-Side & Front-to-Rear).
Need to Shift Left or Rear Percentage? Move physical lead or component mass within the car.
Adjusting Ride Height: Re-check ride height anytime ballast/lead is relocated.
2. Adjusting Cross-Weight (Wedge)
Adjust cross-weight using your jack screws or coil-over adjusters:
To ADD Cross-Weight: Turn IN (raise) the RF and LR; turn OUT (lower) the LF and RR.
Non-Coilover Note: You may need 2 turns on the rear for every 1 turn on the front.
Pro-Tip: Adjusting all four corners simultaneously maintains your overall ride heights.
3. Set Sway Bar Preload
With the car resting on the scales, reconnect and adjust your sway bar. The digital display lets you see exact preload changes as you adjust the links.
âť“ Frequently Asked Questions (FAQ)
Should I scale with the driver in or out of the car?
Driver in is recommended. Driver weight significantly influences corner weights. Scaling with the driver in the seat yields the most repeatable, real-world results.
Alternative: Scaling without a driver works if you consistently factor in the exact weight differential and resulting ride height changes, but it introduces more variables.
How level do scale pads really need to be?
They must remain in the same plane.
If you tilt the entire plane evenly (e.g., lower the front by 1 inch while keeping pads coplanar), the effect on scale readings is minimal.
However, if a single corner or opposing corners are raised out of plane (even by a 1/2 inch shim), your cross-weight numbers will warp significantly. Keep all four pads as perfectly level to one another as possible.
Do I need to re-zero scales after making chassis adjustments?
No. Modern computer scale systems allow multiple adjustments without re-zeroing. Simply make your chassis changes, settle the car, and read your new numbers.
Can I adjust Left-Side or Rear-Weight percentages using jack screws?
No. Turning jack screws only alters cross-weight (wedge) and corner weight distribution—it does not shift overall Left-Side or Rear-Weight percentages. To change overall balance percentages, you must physically relocate lead ballast or heavy components within the chassis.