THE TOOLS
BATTERY SIZING
Weight, gearing, kV, cells and pack IR → peak amps, sag and motor load. Live tuner plus a 3-car table.
GEARING
Motor pinion → spur → diff pinion → ring → wheel. Final drive, rollout, top speed and motor load.
DRAG PAK WEIGHT
Find the lightest mix of cells and supercapacitor strings that holds voltage through the launch.
RIPPLE PAK
Phase current, duty and PWM in → a real orderable capacitor bank out, with heat, voltage margin and resonance checked.
THE GUIDES
BURST PHYSICS
What really limits a motor in a 2 second pass: copper heat, saturation, magnet demagnetization, rotor speed, timing and windings.
RIPPLE PAK GUIDE
Size the capacitor bank your ESC actually needs — ripple current, ESR, heat per pass, and the bus resonance that makes more microfarads worse.
GEARING GUIDE
Pinion, spur, ring and pinion: how the gears multiply, rollout and top speed, in pictures.
DRAG BATTERY SIZING GUIDE
Size a 132 ft drag pack by internal resistance and sag, not the label C rating.
WHERE IT STARTED
319 LB FOR 32 FT
The 2015 world-record puller: 319 lb pulled 32 ft. Everything on this site grew out of builds like this one.