The sliding-gear gearbox
Engineers (Advanced), mission M3 Gearboxes: How Cars Go, lesson 1 of 6.
Hook
Old cars had gears you slid into place. Crunch! Let’s build one.
Fair test
Measure distance per crank in each gear. Calculate each ratio from the teeth.
Bonus challenge
Why does it crunch if you shift while moving? Explain it to a partner.
The build
🕹️ Sliding-Gear 2-Speed Cart: Your first real gearbox: slide the crank axle to switch between strong gear and fast gear! (level 2 of 5, about 22 minutes, 8 steps)