wheelie

Articles, guides, and products tagged "wheelie" — a combined view of every catalogue resource on this topic.

User guide

Mass distribution, center of gravity and longitudinal load-transfer engineering on an e-scooter: static F_z,f / F_z,r, dynamic ΔN = m·a·h/L, wheelie / stoppie thresholds, anti-squat / anti-dive geometry and optimal brake bias

Mass distribution is the invariant through which all longitudinal forces pass: what the motor creates, the brake dissipates, and the tire transfers to the road **fundamentally depends on the static F_z,f and F_z,r at the wheels and on the dynamic ΔN = m·a·h/L under acceleration or braking**. The canonical [«Brake system engineering» article](@/guide/brake-system-engineering.md) unpacks caliper hydraulics; [«ABS engineering»](@/guide/anti-lock-braking-system-engineering.md) — the control loop that keeps slip ratio λ in the peak-friction window; [«Smooth acceleration and throttle control»](@/guide/acceleration-and-throttle-control.md) — rider technique for launch with weight-transfer control. This deep-dive is a distinct engineering-axis that consolidates these three rider-side contexts into a single mass-distribution design discipline: where to mount the battery (deck vs stem), what wheelbase to target (1000 mm vs 1150 mm), what optimal brake bias looks like (≈70/30 vs 50/50), why an e-scooter with short wheelbase L=1000 mm and high CG h=1.2 m has **2-3× the load-transfer sensitivity of a motorcycle** with L=1400 mm and h=0.7 m. Newton's framework: a rigid body has F = m·a and ΣM = I·α; static normal forces F_z,f = mg·b/L and F_z,r = mg·a/L (where a, b are distances from CG to the front / rear axle); dynamic transfer ΔN = m·a·h/L under longitudinal acceleration. Canonical engineering sources ENG-first: Gillespie «Fundamentals of Vehicle Dynamics» SAE 1992 ISBN 978-1-56091-199-9 §1.5 (axle loads), §3 (acceleration performance), §4 (braking performance); Cossalter «Motorcycle Dynamics» 2nd ed. 2006 ISBN 978-1-4303-0861-4 §6 longitudinal dynamics; Foale «Motorcycle Handling and Chassis Design» 2nd ed. 2006 ISBN 978-84-933286-3-4; Pacejka «Tire and Vehicle Dynamics» 3rd ed. 2012 Butterworth-Heinemann ISBN 978-0-08-097016-5 §1; Wong «Theory of Ground Vehicles» 4th ed. 2008 Wiley ISBN 978-0-470-17038-0; Genta & Morello «The Automotive Chassis» Vol 1 2nd ed. 2020 Springer ISBN 978-3-030-35634-0; ISO 8855:2011 axis convention; EN 17128:2020 PLEV; ECE R78 motorcycle reference.

15 min read

User guide

Smooth acceleration and throttle control on an e-scooter: longitudinal weight-transfer physics, jerk-limited ramp, controller soft-start, slippery-surface launch, wheelie risk on a high-CoG deck, and throttle calibration

Acceleration is the longitudinal mirror of braking: the same weight-transfer, but with the sign flipped. Under a hard throttle opening, the motor torque at the rear wheel generates an equal reactive torque on the frame, which pitches the scooter nose-up; the rider's body inertia simultaneously moves rearward. The front wheel unloads — in the limit, it lifts off (wheelie); in the typical case, it loses lateral grip on a corner or a small bump. On an e-scooter, the throttle is not a 'gas pedal' in the traditional sense: between your finger and the stator winding sit a Hall sensor (0.84–4.2 V), a controller with PWM modulation and its own soft-start ramp, the BMS, and finally the motor with MOSFET switches. Each layer adds its own latency (5–50 ms), its own noise floor, and its own limit: an over-driven MOSFET → 150 °C cutoff, a displaced throttle magnet → ghost-throttle in the cold, an overly aggressive ramp in sport mode → a wheelie on a 30 % gradient. Jerk — the second derivative of velocity, m/s³ — has a medical comfort threshold for car passengers of ≈ 0.3–0.9 m/s³ ([ScienceDirect — Standards for passenger comfort in automated vehicles, 2022](https://www.sciencedirect.com/science/article/pii/S0003687022002046)), but on a high-CoG, short-wheelbase e-scooter, even 1.5 m/s³ means a sharp deck pitch and finger-strain on the throttle. CPSC counts 50 000 ED visits in 2022 alone, 94 % of which were solo-falls with no other vehicle involved ([CPSC — E-Scooter and E-Bike Injuries Soar, 2024](https://www.cpsc.gov/Newsroom/News-Releases/2024/E-Scooter-and-E-Bike-Injuries-Soar-2022-Injuries-Increased-Nearly-21)); among typical mechanisms — stuck throttle (Apollo recall 2025) and uncontrolled acceleration on a slippery surface. This is a drill-oriented guide: physics, weight redistribution, jerk-limited ramp, soft-start vs sport mode, slippery launch, wheelie risk, ghost-throttle troubleshooting, a daily launch protocol with a 2–3 mph kick-start, and a 30-min weekly drill in an empty lot. ENG-first sources: MSF Basic RiderCourse, Wikipedia (Jerk physics, Wheelie, Weight transfer, Bicycle-and-motorcycle dynamics), Inside Motorcycles / Data for Motorcycles on the friction circle, Lime / Bird operator manuals, NAVEE on TCS, Apollo, GOTRAX, Levy Electric throttle guides, marsantsx on controller thermals, CPSC injury data.

13 min read