How does rack and pinion steering work?
A gear rolling on a straight rack slides it sideways. A rack is a straight row of teeth. When a small gear — the pinion — turns on it, the rack slides left or right. Real cars use this to turn the front wheels when you turn the steering wheel.
Try Ripcord Top Launcher for freeComplete MightyCog booklet collection: 82 PDF booklets for $12.99. Instructions only; individual booklets remain free.
Explore the printable packTry it yourself
Turn the steering wheel and watch the rack slide. Which way do the wheels point?
Build it: 14 builds that teach rack & pinion steering
- 🌪️ Ripcord Top Launcher: Pull a toothed rack and watch two gear stages turn the top. (level 2 of 5, about 20 minutes, 18 steps)
- 📏 Rack Travel Bench: Turn a small gear and measure the straight travel of a captured rack. (level 3 of 5, about 25 minutes, 13 steps)
- 🏎️ Steering Go-Kart: Turn the steering wheel and the front wheels really turn — just like a real car. (level 3 of 5, about 30 minutes, 25 steps)
- 🏎️ Ackermann Soapbox: Real car steering: the inside front wheel turns more than the outside one, so the tyres never scrub! (level 3 of 5, about 35 minutes, 20 steps)
- 🚀 Launch-Lock Racer: Wind it up, and a little catch holds the spring tight until YOU press the launch button! (level 3 of 5, about 40 minutes, 21 steps)
- 🌀 Pull-back Diff Racer: A spring racer with a real differential, so it zooms round curves without skidding. (level 3 of 5, about 40 minutes, 23 steps)
- 🎛️ One Motor, Knob Steering: The motor drives, YOU steer — turn the knob as you walk beside it. (level 3 of 5, about 40 minutes, 21 steps)
- 🛠️ Ratchet Car Jack: Crank the handle — click, click, click — and lift a toy car. Let go and it stays up! (level 3 of 5, about 35 minutes, 15 steps)
- 🛗 Scissor Lift: Turn the crank and the platform climbs straight up on criss-cross legs. (level 3 of 5, about 45 minutes, 29 steps)
- 🔄 Reverse-to-Turn Car: Only one motor — but it can still turn! Drive backwards and the wheels swing round. (level 4 of 5, about 50 minutes, 24 steps)
- 🎮 First RC Car (Servo): Your first remote-control car: one dial drives, the other dial steers. (level 4 of 5, about 50 minutes, 27 steps)
- 🚞 Cog Railway Climber: A mountain train that grips a toothed rail — it climbs super steep ramps and never slides back. (level 4 of 5, about 55 minutes, 20 steps)
- 🏆 RC Racer: A real remote-control car: motor drive, differential, servo steering and headlights. (level 5 of 5, about 75 minutes, 38 steps)
- 🏆 Independent Rally Car: Every wheel on its own springy arm, a differential, universal joints and Ackermann steering. (level 5 of 5, about 90 minutes, 47 steps)
In the classroom
- M1 Force, Mass & Motion (Engineers, Advanced)
Common engineering questions
How can I try rack & pinion steering at home?
Turn the steering wheel and watch the rack slide. Which way do the wheels point?
Which builds teach rack & pinion steering?
14 MightyCog builds teach it: Ripcord Top Launcher, Rack Travel Bench, Steering Go-Kart, Ackermann Soapbox and Launch-Lock Racer and more. Start with Ripcord Top Launcher: 18 steps, about 20 minutes.