🏎️ RC Tuner

Module 5 Β· The Physics That Wins Races

πŸŒ€ Cornering Dynamics

Camber gain, weight transfer, 4-corner loads, balance β€” understand WHY your car grips.

Lesson 1 of 5

πŸ“ˆ Camber Gain β€” Dynamic Camber

Static camber β‰  corner camber. As the suspension compresses, camber changes. The RATE of change = camber gain.

When you set -2Β° camber at static ride height, that's NOT what the tire sees in a corner. As the car rolls, the outside suspension compresses, and the camber gets MORE negative.

Camber gain is how much camber changes PER mm of suspension compression. Measured in Β°/mm.

High camber gain (0.3-0.5Β°/mm): Tire gets very negative in corners. Great for lateral grip. Can lose straight-line grip because static camber is mild.

Low camber gain (0.1-0.2Β°/mm): Camber stays consistent. Less peak corner grip but more predictable and more straight-line grip.

Camber gain calculator

Dynamic camber in corner: -2.9Β°
πŸ“Š See it live

The Kinematics tool in the RC Tuner shows camber gain in real-time. Open it, roll the car, and watch the camber number change. This is your setup truth.

Lesson 2 of 5

βš–οΈ Weight Transfer β€” The Fundamental Force

Grip follows load. Weight transfer determines which tires have the most grip at any moment.

Weight transfer is physics: when the car accelerates, brakes, or corners, load shifts between tires. The formula is:

Lateral Weight Transfer = (CG Height Γ— Lateral G) / Track Width

Higher CG = more weight transfer. Wider track = less weight transfer. More lateral force = more transfer.

Why it matters: A tire with more load can generate more FORCE (more grip). But the relationship is not linear β€” doubling load doesn't double grip. This is why weight transfer management = speed.

Weight transfer calculator

Lateral weight transfer
17g
~3.8% of static corner weight (375g)
πŸ’‘ Minimize weight transfer = maximize total grip

Because tire grip curves are non-linear, a balanced load across all 4 tires generates MORE total grip than one heavily-loaded tire and three light ones. Low CG + wide track = better total grip.

Lesson 3 of 5

🎯 4-Corner Loads β€” Where the Grip Is

At any moment, each corner carries different weight. The LIMITING tire is the one with the MOST load.

In steady-state cornering, load distribution looks like this (typical touring car):

Outside-rear: Highest load (braking + cornering combined) β†’ this is your LIMITING tire
Outside-front: Second highest (cornering, less weight transfer)
Inside-rear: Lightly loaded
Inside-front: Lightest (can almost lift off ground in extreme corners)

Your fastest lap is limited by the tire with the MOST load β€” because that tire reaches its grip limit first (grip curves are non-linear).

Interactive β€” watch load shift through a corner

FL36% FR36% RL14% RR42% ← Turning left Right rear is the limiting tire
Outside rear carries the most load at steady-state cornering. This tire limits your corner speed.
⚠️ The limiting tire rule

You can't gain corner speed by adding more load to a tire β€” beyond a certain point, more load = less grip coefficient. The key is balancing load across all 4 tires.

Corner weight scales measure your static weight distribution. Use them to check front/rear balance and left/right symmetry.

Lesson 4 of 5

βš”οΈ Balance β€” Understeer vs Oversteer

The balance between front and rear defines your handling character. Find the sweet spot.

Neutral: Front and rear grip limits reached simultaneously. Ideal but unstable β€” any perturbation causes spin.

Understeer (push): Front reaches grip limit BEFORE rear. Car won't turn as much as steering input demands. Safer but slower in transitions.

Oversteer (loose): Rear reaches grip limit BEFORE front. Car rotates more than steering demands. Fast but requires skill.

Touring car tuning target: Slight understeer at corner entry (safe, predictable), transitioning to neutral or slight oversteer at corner exit (rotation on throttle).

How to shift the balance

Towards MORE front grip (reduce understeer / add oversteer):
β€’ Add front camber (-0.5Β°) Β· Soften front spring Β· Reduce rear camber Β· Stiffen rear spring Β· More front droop Β· Less rear toe-in
Towards MORE rear grip (reduce oversteer / add understeer):
β€’ Reduce front camber Β· Stiffen front spring Β· Add rear camber Β· Soften rear spring Β· Less front droop Β· More rear toe-in
Towards NEUTRAL (both limits at once):
β€’ Equal spring rates Β· Similar camber F/R Β· Equal droop Β· Minimal toe Β· High roll center all around

Quick check

Car pushes under braking. Simplest fix?
Lesson 5 of 5

πŸ—ΊοΈ Track-Specific Tuning

Every track is different. Learn the track TYPE, then pick your base setup before fine-tuning.

Don't start from scratch every track. Categorize first, then start from a known-good base, then tweak for specifics.

Track categories:

🏎️ High-speed: Long straights, sweeping corners. Priority = stability, low drag.
πŸ”§ Technical: Short straights, many direction changes. Priority = rotation, agility.
🎯 Mixed: Balance of both. Priority = adaptability, neutral base.
🏁 Stop-start (speedway): Tight hairpins, very short straights. Priority = corner exit power delivery.

Speed category β†’ FDR target guide

Speedway / Large-FastFDR 3.30
Medium-FastFDR 3.40
MediumFDR 3.50
Medium-TightFDR 3.60
Tight / Stop-startFDR 3.70
Higher FDR = shorter gear (more RPM) = motor runs COOLER. Lower FDR = taller gear = motor runs HOTTER.
⚠️ Gearing rule

Higher FDR = shorter gear = COOLER motor (more RPMs per speed, motor works in efficient range). Lower FDR = taller gear = HOTTER motor (less RPMs, more load).

This is counter-intuitive. Remember: "Higher = Hoter" is WRONG. "Higher = Cooler" is correct.

Track type β†’ setup priority

High-Speed
  • Lower FDR (taller gear)
  • More rear camber (stability)
  • Lower F RC, higher R RC
  • Stiffer springs overall
Technical
  • Higher FDR (shorter gear)
  • More front camber (turn-in)
  • Higher F RC (crisp response)
  • Softer front spring

🏁 Module 5 Complete!

You now speak the language of physics. Ready to master the hardware: tires, diffs, and aero.

Start Module 6: Tires, Diffs & Aero β†’