How does a gearbox work?
A box of gear pairs where you choose which pair works. A gearbox holds several gear pairs on the same two axles. Only one pair is "switched on" at a time, so you can pick fast-and-weak or slow-and-strong without rebuilding the car. Real cars change gear to start off strong and then cruise fast.
Try Sliding-Gear 2-Speed Cart for freeGearbox & Drivetrain Cars booklet pack: 30 PDF booklets for $5.99. Instructions only; individual booklets remain free.
Explore the printable packTry it yourself
Turn the input axle once in 1st gear and count the output turns. Now shift to 2nd and count again!
Build it: 5 builds that teach gearbox
🕹️ 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)- 🎚️ Two-Speed Pull-back: Choose your gear before the race: CLIMB or SPRINT! Slide the back axle to swap gears. (level 3 of 5, about 35 minutes, 13 steps)
- ⚙️ Clutch-Gear 2-Speed Car: Push the gear lever and a driving ring grabs a different gear: 1st climbs, 2nd races! (level 3 of 5, about 45 minutes, 18 steps)
- ↩️ Reverse-Gear Truck: The motor only spins one way — the gear lever decides forwards or backwards! (level 4 of 5, about 55 minutes, 18 steps)
- 🏁 Three-Speed Car: Two little gearboxes in a row make a big one: crawl, cruise or fly! (level 4 of 5, about 60 minutes, 20 steps)
In the classroom
- M3 Gearboxes: How Cars Go (Engineers, Advanced)
Common engineering questions
How can I try gearbox at home?
Turn the input axle once in 1st gear and count the output turns. Now shift to 2nd and count again!
Which builds teach gearbox?
5 MightyCog builds teach it: Sliding-Gear 2-Speed Cart, Two-Speed Pull-back, Clutch-Gear 2-Speed Car, Reverse-Gear Truck and Three-Speed Car. Start with Sliding-Gear 2-Speed Cart: 8 steps, about 22 minutes.