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Dirt Track Wedge Setup Guide: Simple Steps for Speed

If you’re new to dirt racing, wedge (also called cross weight) can feel mysterious. This dirt track wedge setup guide explains what wedge is, why it matters, and how to set it the right way on your Street Stock, Sport Mod, IMCA Modified, or Late Model. You’ll learn step-by-step scaling, baseline targets for tacky versus slick tracks, the tools you actually need, and the mistakes I see beginners make most often.

Dirt track wedge setup guide: Why it matters

  • Wedge/cross weight is the percentage of total vehicle weight carried by the right-front (RF) and left-rear (LR) corners together.
  • Formula: Cross Weight % = (RF + LR) á Total Weight × 100
  • What it does on dirt:
    • More wedge (higher cross %) usually tightens the car on throttle, especially from center-off.
    • Less wedge frees the car up, improving rotation but risking a loose-off condition on slick.
  • Why beginners should care: Correct wedge helps you put power down off the corner without excessive wheelspin or push. It’s one of the quickest, legal adjustments you can make on race day.

Typical safe starting points (always check your chassis builder’s notes and class norms):

  • Heavy/tacky track: 50–52% cross weight
  • Average/transition: 52–55%
  • Slick/black: 55–58% (some stock-chassis cars go a hair higher; use small steps)

Note: These are general dirt-track baselines. Chassis design, rear suspension type (4-bar, swing-arm, leaf), left/rear percentage, and driving style all influence the “right” number.

How to set wedge (cross weight) step-by-step

  1. Prepare the car
  • Ride heights at baseline. Verify springs, shocks, bars, and links match your setup sheet.
  • Set tire pressures to hot targets if you know them, or consistent “scaling” pressures (e.g., LF 12, RF 14, LR 12, RR 14 psi).
  • Fill fuel to the amount you’ll start with for the race or heat.
  • Place ballast and tools exactly where they’ll be during competition. Secure everything.
  1. Level the scales
  • Use a known-level pad or shim scales until all four pads read level on a digital angle finder.
  • Zero the scales with nothing on them.
  1. Put the car on scales correctly
  • Roll the car on, bounce each corner lightly, and settle the suspension by rolling forward/back a few inches without turning the wheel.
  • Driver in full gear in the seat (or equivalent ballast at the correct height). Belts tight. Steering straight.
  1. Record weights and calculate
  • Write down LF, RF, LR, RR and total weight.
  • Compute cross weight % = (RF + LR) á Total × 100.
  • Also note left % and rear % for your logbook.
  1. Adjust wedge safely
  • Use jack bolts/coilover collars to change spring preload. One corner at a time, in small steps.
    • To increase cross %: Add turns to RF and/or LR, or remove turns from LF and/or RR.
    • To decrease cross %: Add turns to LF and/or RR, or remove turns from RF and/or LR.
  • Typical change per 1 turn varies by thread pitch and motion ratio (often 10–30 lb per corner). Measure your car: make a 1-turn change at one corner and note the weight change for future reference.
  • After each adjustment: Settle the suspension again and recheck.
  1. Re-verify ride heights and alignment
  • Wedge changes can nudge ride heights. Confirm you’re still at baseline.
  • Recheck toe and steering wheel center before loading up.

Example:

  • Total: 3,000 lb. RF 780, LF 720, LR 840, RR 660.
  • Cross % = (780 + 840) á 3000 × 100 = 54%.
  • If the track’s going slick and you’re loose off, try +0.5 turn LR (+10–15 lb typical) or -0.5 turn RR, recheck, and test. Small steps win.

Safety notes:

  • Always support the chassis with stands before putting your hands near springs or links.
  • Keep fingers clear of coilover collars and jack bolts when the car’s on scales.
  • Torque jam nuts and verify that springs aren’t binding at full droop.

Key things beginners should know

  • Wedge mainly affects mid-corner to exit balance. If you’re tight on entry, look first at brake bias, rear bar/J-bar heights, and front geometry—not just wedge.
  • Track changes quickly. A number that feels perfect in hot laps might be too free as the surface takes rubber. Keep notes and adjust gradually.
  • Left % and rear % change how wedge “feels.” More rear % amplifies exit effects; more left % can help consistency but may hurt rotation if overdone.
  • Tire stagger matters: More rear stagger helps turn-in and frees the car on exit—too much can make you loose off even with higher wedge.
  • Fix the driver too: Smooth throttle application and straight wheel on exit can “add” effective wedge. Don’t tune around a heavy right foot.

Equipment, tools, and realistic costs

Must-haves:

  • 4-corner scales ($800–$2,000 used; $2,000–$3,500 new)
  • Accurate tire pressure gauge and pyrometer or temp probe
  • Tape measure, toe plates or strings, caster/camber gauge
  • Digital angle finder for ride heights and bar/J-bar angles
  • Setup notebook or simple spreadsheet

Nice-to-haves:

  • Setup pads/leveling plates
  • Turnplates for the front end
  • Wheel spacers and a quick way to change stagger
  • Durometer for tire consistency

What you don’t need (at first):

  • Exotic data systems. A disciplined logbook and consistent procedures beat gadgets early on.

Expert tips to improve faster

  • Change one thing at a time. If you adjust wedge and J-bar together, you won’t know which helped.
  • Work in small increments. 1/4–1/2 turn per change is enough for most dirt conditions.
  • Baseline cards win weekends. Keep a “Heavy,” “Average,” and “Slick” baseline in your notes with wedge %, tire pressures, and bar heights.
  • Validate with lap-time deltas. If your change doesn’t show up in the stopwatch or drivability notes, consider reverting.
  • Re-scale after contact or big curb hits. Bent parts make wedge numbers lie.
  • Watch entry vs. exit: If the car rotates great on entry but is loose off, add wedge or reduce rear stagger slightly. If it won’t turn in, try less wedge or adjust front geometry/brake bias before cranking big changes.
  • Communicate simply: “Tight center,” “loose off,” “snaps loose with throttle” gets you to the right wedge move quicker than vague feedback.

Common beginner mistakes

  • Chasing entry push with wedge. Wedge is not the first lever for corner entry. Fix brake bias, front shocks/springs, or rear roll center first.
  • Scaling on an unlevel floor. A 1/4-inch slope can swing cross by a full percent or more.
  • Not settling the suspension. Always roll the car and bounce corners before reading numbers.
  • Big swings. Two full turns on a jack bolt can ruin a night. Use 1/4–1/2 turns, test, then continue.
  • Ignoring tire pressures. If RR lost 2 psi, your wedge readout and handling both change.
  • Forgetting the driver. Always scale with the driver or equal ballast, belts tight.

FAQs

Q: What’s the difference between wedge and cross weight? A: They’re the same thing in circle track slang. It’s the RF+LR diagonal load expressed as a percentage of total weight.

Q: Do I scale with the driver in the seat? A: Yes. Full gear, belts tight, steering straight. If the driver can’t sit in, place ballast at the same height and position.

Q: How many jack-bolt turns equal 1% cross? A: It depends on thread pitch and motion ratio. On many dirt cars, 1/2 to 1 turn at one corner moves cross roughly 0.3–0.7%. Measure your car to know for sure.

Q: Will more wedge fix a push on entry? A: Usually not. Wedge mainly helps mid-to-exit. For entry push, look at brake bias, front springs/shocks, front ride height/camber, and rear roll center.

Q: Does stagger change wedge? A: Stagger doesn’t change the static cross % reading, but it strongly affects how the car feels. More rear stagger frees the car, mimicking “less wedge” on exit.

Q: Should I change wedge for heat vs. feature? A: Yes, if the track changes. As it slicks off, many teams add a small amount of wedge (and/or adjust J-bar) to improve drive off.

Conclusion

Mastering wedge is about consistency: scale on a level surface, make small, deliberate changes, and keep excellent notes. Start with safe baselines, listen to what the car tells you mid-to-exit, and don’t try to fix every handling issue with wedge alone. Do that, and you’ll find forward drive sooner, save your tires, and make cleaner passes off the corner.

Next steps: Build your Heavy/Average/Slick baseline sheets, measure how much 1/2 turn changes cross on your car, and log every change with track conditions and lap times.

Optional suggested images:

  • Photo: Car on level scales with LF/RF/LR/RR weights labeled.
  • Diagram: Which jack-bolt directions increase/decrease cross weight.
  • Chart: Sample baseline wedge % for heavy, average, and slick track conditions.