Tip-Over & Traction Stability Calculator
Rigid-body statics for your drivetrain: how hard you can turn or accelerate before two wheels lift, the tip angle on a ramp or cross-slope, whether you slide or tip first, and how hard you can push. Everything recomputes live.
Figures: 2026 REBUILT season (Game Manual R103 / R104). Verify weight, envelope, carpet spec, and vendor µ against the current FIRST Game Manual — these change most seasons.
Lateral wheel-contact spacing. Default 27 in (R104-bounded estimate — adjust to your drivetrain).
Fore/aft wheel-contact spacing. Default 27 in (R104-bounded estimate).
Engineering estimate, NOT a published spec — the #1 error source. A 2 in miss moves every result 10–20%. Measure it (balance/tip test).
Robot + bumpers + battery. Default 125 lb is an estimate — enter your measured weight.
Highest-traction common FRC tread. Community values cluster ~1.1–1.3 (AndyMark blue-nitrile page lists no numeric CoF).
Community / historical estimates — not currently vendor-published. Preset seeds the low end of the range; slide within it or measure your own.
F ≈ µ · f · weight. Only as accurate as µ (~1.1–1.3); treat as a range, not a certified number.
Tier 1 (exact): tip accelerations, SSF, and tip angles are rigid-body statics — as correct as your inputs. Tier 2 (estimate): pushing force and the slide-vs-tip verdict depend on µ, which is empirical and variable.
Notes & sources
- Tip angles, tip accelerations, and the Static Stability Factor are exact rigid-body statics for the geometry you enter — as correct as your inputs. The dominant error is CoG height: measure or estimate it, don't guess.
- Real robots tip a little differently than ideal statics: wheel scrub, tread squish, bumper/frame ground contact, suspension travel, and dynamic (not steady-state) maneuvers all shift the real threshold. Treat results as a well-founded design guide with margin, not a guarantee.
- The pushing-force number and the slide-vs-tip verdict depend on the wheel-carpet coefficient of friction, which is empirical and varies with carpet age, wheel wear, dust/debris, and downforce. Shown as an estimate/range, never a single certified value.
- Weight and size defaults are the 2026 REBUILT legal maxima (R103 = 115.0 lb excluding bumpers/battery; R408 caps robot + bumpers at 135.0 lb; R104 = 110.0 in perimeter, 30 in tall). These change most seasons — re-verify against the current game manual and always enter your own measured numbers.
- Coefficient-of-friction presets assume the official Shaw Floors Philadelphia Commercial Neyland II 20 competition carpet. Behavior on shop floor, tile, or other carpet will differ.
- g = 9.80665 m/s² (32.17405 ft/s²) — NIST CODATA standard acceleration of gravity, defined/exact. physics.nist.gov
- Robot weight ≤ 115.0 lb(52.16 kg), excl. bumpers & battery — 2026 REBUILT R103. Robot + bumpers ≤ 135.0 lb — R408. firstfrc.blob.core.windows.net
- Perimeter ≤ 110.0 in, height ≤ 30 in — 2026 REBUILT R104 (bounds the geometry inputs). firstfrc.blob.core.windows.net
- Defaults: track/wheelbase 27 in, CoG height 13 in, weight-on-wheels 125 lb — engineering estimates (R104-bounded), editable. CoG height is NOT a published spec and is the dominant error source.
- µ presets & default 1.1 — community / historical estimates (mrmctavish blog; Chief Delphi; WCP/AndyMark pages), NOT currently vendor-published. User-editable. mrmctavish.wordpress.com
- Field carpet: Shaw Floors Philadelphia Commercial Neyland II 20 — 2026 field dimension drawings. firstfrc.blob.core.windows.net
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