How To Run The Bottom In Iracing Dirt Ovals

Master How To Run The Bottom In Iracing Dirt Ovals: step-by-step lines, brake/throttle cues, setup tweaks, and drills to pass cleanly, stay fast the top goes away.

If you’re tired of getting stuck behind the cushion crowd and want clean passes without sending sliders, you’re in the right place. This guide shows you exactly how to lock your left-side tires to the moisture, rotate without washing up, and finish corner-exits strong. You’ll learn the line, the inputs, and the setups that make the low lane work in iRacing.

Quick answer: To run the bottom, slow your entry earlier than you think, turn in shallow, and use a short, gentle brake brush to set the nose. Hold a light “maintenance throttle” through the center to keep the car planted, then squeeze back to power as you unwind the wheel. Keep your left-sides on the last strip of moisture and never let the car float off the bottom on exit.

What “the Bottom” Means—and Why It Wins Races

Running the bottom means keeping your left-side tires near the inside berm/marking (white line, tractor tires, or wall) and tracing the shortest legal path around the corner. On dirt, the fast lane moves with the moisture. When the top is stacked or the track slicks off, the low lane can be faster—shorter distance, cleaner air, and fewer yellows.

Key terms you’ll see:

• Cushion: The built-up ridge of dirt near the outside wall. Fast but risky.
• Berm: The inside ridge/edge. Some tracks have a distinct dirt mound or tires; others have just a painted line.
• Marbles: Loose, rolled-up dirt that’s like ball bearings—avoid.
• Tight/Loose: Tight = won’t turn (pushes up the track). Loose = rear steps out (oversteer).

Bottom line benefits:

• Shorter distance = lower lap time with the same average speed.
• Safer passes without divebomb sliders.
• Tire and temp management for the right-rear (less wheelspin, more traction late in runs).
• Track-position defense when everyone else pounds the cushion.

How To Run The Bottom In Iracing Dirt Ovals: Step-by-Step

Follow this sequence in a test session before you try it in a race.

1. Entry: Slow in to be fast out

• Lift earlier than usual—about a car-length before your normal cushion entry point.
• Turn in shallow, aiming for a line that puts your left-front within 6–18 inches of the berm/line.
• Feather 5–15% brake for half a second to “set the nose” and create rotation. This is a brush, not a stomp.

2. Mid-corner: Glue the left-sides to moisture

• Hold 10–25% “maintenance throttle” to keep weight on the rear tires so the car doesn’t snap loose.
• Keep very small steering inputs; if you’re sawing the wheel, you’re too fast or too high.
• Watch for the thin, slightly darker strip of moisture inside the black slick. That’s your rail.

3. Exit: Unwind first, then squeeze power

• Start straightening the wheel before you add big throttle.
• Add throttle smoothly (think: squeeze over 1–2 seconds). If the rear hops or wheelspins, you got greedy—reset and try again.
• Keep the car low to the exit curb and let it drift only as much as needed to stay straight. If you float two lanes up, you gave away the bottom.

4. Visual markers that help

• Pick a turn-in cone/sign and use it every lap.
• Identify the inside “seam” (moisture/gloss line) and commit to it.
• If the inside berm is tall (Fairbury-style), approach it at a micro-angle and ride beside it; don’t climb onto it.

5. Passing with the bottom

• Nose inside by entry, keep it pinned to the moisture, and be patient. The pass often completes on corner-exit as the top car pinches themselves and you drive off straighter.
• If they cut down late, you’re already low—hold your line. Don’t chase; make them lift.

Car-specific cues (fixed and open sets):

• Winged Sprints (305/360/410): Add a click or two of wing angle or move the wing back for more front grip and stability on entry. Use very light brake; throttle is your balance tool.
• Late Models/Street Stocks/UMP Modifieds: A little more brake on entry, then early, smooth throttle. These cars like to “park + pivot + drive.”

Target rhythm (a starting point to tune):

• Entry lift: 60–80% throttle → short 5–15% brake
• Mid: 10–25% throttle steady
• Exit: 40–80% throttle as wheel unwinds

Key Things Beginners Should Know

• Bottom speed lives in patience. If you overshoot entry by 2 mph, you’ll wash up and lose the whole corner.
• Track state matters: On green/tacky, the absolute inside is lightning. As it slicks, the optimal bottom is a half-lane off the berm where the last moisture hides.
• Momentum vs. distance: The top may feel faster because it’s loud and sideways. Your stopwatch only cares about lap time—short and straight usually wins.
• Watch dirt color: Dark-damp = grip. Brown-slick/black ice = patience and feathered throttle. Marbles = no-go.
• Don’t downshift on dirt ovals. Street Stocks, Late Models, and Mods hate it. It unsettles the rear and kills traction.
• Defend without weaving: If you’re holding the bottom, commit early on entry so the guy behind knows. Don’t drop from top to bottom late.

Setup and Control Tweaks That Help the Low Line

Fixed setup? You still have tools.

• Brake bias: Move 1–3% rearward to help rotation on entry without locking rears. If it snaps loose mid-corner, go back toward front.
• Winged Sprints: +1–2 degrees wing angle or move wing back slightly for entry stability; slide forward if you need more straightaway speed.
• Tire pressures (open sets): Slightly lower RR pressure or slightly higher LR pressure can calm exit and help drive off. Make small changes (0.5–1.0 psi).
• Stagger (open sets): Reducing rear stagger helps the car “park and turn” on the bottom; too little makes it tight off. Change in tiny steps.
• Gearing: Don’t over-gear. If you’re spinning the RR on exit, gear taller or manage throttle better.
• Wheel/pedal settings:
  • Linear throttle. Smooth foot = smooth car.
  • Brake gamma around 1.0–1.4 (higher if you have a basic potentiometer pedal to gain control).
  • Steering range 540–720° with a stable force feedback; avoid oscillations.

Expert Tips to Improve Faster

• Three-lap drill: Run three consecutive laps with the left-front no more than a tire width off the line. If you float up mid-corner, reset.
• No-spike throttle drill: Watch iRacing’s F9 pedal overlay. Keep the bar smooth; no sudden 0→100% pops on exit.
• Ghost the fast line: Load a fast lower-line ghost or replay and copy their turn-in and throttle cues for 5 laps.
• “Breathe, don’t brake” drill: On a slick track, try one session where you only lift (no brake) to learn speed discipline. Then add a tiny brake brush once you feel consistent.
• Learn the seam: In late runs, the fastest bottom is often 1–2 feet off the berm where a thin dark seam forms. Aim left-front for it every lap.
• Racecraft: If you’re inside and equal at entry, commit. If you’re a half-car back, don’t force a slider—stay low, pressure them into a mistake, and drive off straighter.

Common Beginner Mistakes (and Fixes)

• Entering too hot and washing up

  • Why: You’re carrying cushion entry speed to a shorter line.
  • Fix: Lift one car-length earlier; add a brief 5–10% brake brush.

• Stabbing throttle mid-corner

  • Why: Trying to “catch” a push with power.
  • Fix: Hold 10–25% maintenance throttle; add power only as you unwind the wheel.

• Clipping the inside berm/tires

  • Why: Turning in too early or aiming at the berm instead of alongside it.
  • Fix: Turn in shallow; target a line 6–18 inches off the edge.

• Rear stepping out on entry

  • Why: Too much rear brake bias or an abrupt lift.
  • Fix: Nudge bias 1–2% forward; smooth your lift; keep a touch of throttle.

• Floating up on exit into traffic

  • Why: Adding throttle before straightening the wheel.
  • Fix: Unwind first, then squeeze throttle; think “straight, then power.”

• Chasing the cushion because it “feels faster”

  • Why: The show is up top; the speed is down low when slick.
  • Fix: Trust the stopwatch/delta. If the bottom is equal or better, commit for five laps and compare.

FAQs

Q: How do I know when the bottom is faster than the top? A: Watch the dirt color and your delta. If a darker seam is forming low and your lap times stabilize or improve when you hug it, the bottom is on. Traffic also makes the bottom strong even if raw pace is similar.

Q: Should I use the brake on dirt? A: Yes—just a brush. Use 5–15% for a moment on entry to set the nose and rotate. If you’re locking or getting loose, reduce pressure or move bias slightly forward.

Q: What’s the best wing setting for the bottom in sprints? A: Add a click or two of angle or move the wing back for entry security. If you feel bogged down on the straights, move it forward a notch. Adjust one change at a time.

Q: Do I diamond the corner or hug the inside the whole way? A: On tacky tracks, a slight diamond can help: in early, rotate, and drive off straight. On slick, a constant, shallow arc that hugs the moisture seam is usually faster and safer.

Q: How close should I run to the berm? A: As close as you can without touching—often 6–18 inches. If the berm is tall, stay off the face and run parallel. If it’s flat, left-sides practically on the paint.

Q: Is the bottom line good in fixed setup races? A: Absolutely. Use brake bias and wing adjustments (where allowed), and focus on entry discipline and throttle smoothness. The line and your feet do most of the work.

Conclusion

Running the bottom isn’t flashy, but it wins races. Slow your entry, keep your left-sides on the moisture, maintain a little throttle through the center, and squeeze out smooth. Practice the three-lap low-line drill and the no-spike throttle drill this week. Nail those, and you’ll pass clean, avoid chaos, and be the calm car rolling past the wrecks on the cushion.

Suggested images (optional):

• Overhead diagram of low-line vs. cushion line with moisture seam highlighted
• Side-by-side throttle/brake overlay showing “stab” vs. “squeeze” on exit
• Track surface progression graphic (tacky → slick → inside seam returning)
• Sprint car wing position infographic for bottom running adjustments