Four people. Four disciplines. One system.
G&M has no legacy and no factory floor of its own. What it has is four people who have each already done the hard thing once, and a way of working that makes them one engineering system, not four resumes. This team has worked together since 2019: three of them building NUMO, its racing brand SLACK, and then KMC, with the fourth backing them on capital and governance from the start. G&M turns that history toward America.
Sungwoo Jeon
A partner to this team since the NUMO days, backing its fundraising and governance from the outside. Now inside: capital strategy, governance, investor relations. The discipline that keeps a small company investable.
Yongwook Jang
From Samsung Electronics mechanical design to co-founder and CEO of NUMO. The modular platform he engineered there, patented years before KALIBER, is the direct ancestor of CHASSIX.
David Chang
Founded NUMO. Led the powertrain and electronics of a 150 km/h production two-wheeler, and built the control stack in house: controllers, BMS, chargers, five patents. Ran the race projects behind the Dubai Cup.
Eugene Lee
Supply chain at 17,000 vehicles a year with a 2022 $20M export award. MES smart factory discipline, ISO 9001 and 14001, and parts SCM for an AI caddie robot.
Not four resumes. One track record, built together.
The team set out to build electric two-wheelers the way cars are built.
David Chang founded it and led the powertrain and electronics. Yongwook Jang, from Samsung Electronics mechanical design, engineered the modular ladder-frame platform and patented its architecture. Sungwoo Jeon backed the company's capital and governance from the outside.
A patented modular platform, a Hyundai Mobis sample program, and a dealer network built from nothing. Out of this work came a powertrain capable of 150 km/h.
A production two-wheeler built to be the fastest of its kind.
David Chang led the powertrain end to end, and the in-house control stack (controllers, BMS, chargers) came out of the same effort.
150 km/h in the team’s own testing, and reviewers call it the fastest production e-scooter in the world. Tested against a championship machine built on a Williams battery and BMS and a YCOM frame, and judged the better ride. Formula E champion Lucas di Grassi has ridden it. That ride opened the next door.
The Dubai Electric Scooter Cup, staged by the Dubai Sports Council and the Federation for Micromobility and Sport.
Through di Grassi came the Federation, and with it a commission: build the race machines themselves. The team wrapped the 920R's frame and powertrain in carbon aero bodywork to create the RS-Zero DXB, and supplied every machine on the grid under its race brand SLACK. David Chang led the race powertrain program; Eugene Lee ran product supply and technical support on the ground.
A one-make race above 100 km/h through Downtown Dubai, where every machine on the grid was the team's.
After Dubai, a designer-led studio arrived with its halo motorcycle: outsourced elsewhere, delivered unable to run.
David Chang led the powertrain and electrical systems. Eugene Lee ran parts supply. The team made it run: the Ciulator, a cafe racer with 1960s lines and a 21st century drivetrain.
Revived as a machine capable of 160 km/h. The halo bike grew into full-size motorcycle development and the Dandelion program that followed.
The racing and engineering core became a manufacturer, KMC, in 2025. In 2026 the full four-discipline team came together as Golf & Mobility.
David Chang (CEO, KMC) and Eugene Lee (COO, KMC) built the production side. Yongwook Jang brought the CHASSIX platform. Sungwoo Jeon moved inside for capital and governance.
The same hands entered four wheels: powertrain and chassis developed in house, and tested. The first product: KALIBER.
