🏁 Pull-back Racer: step-by-step build

Pull-back Racer, completed model

Pull it back, let it go — ZOOM! A racer with a spring for an engine.

This racer has no batteries, but it still drives by itself. How? Hidden inside the grey box is a curly spring. When you roll the car backwards, the spring winds up tight and stores your energy. Let go and the spring unwinds, spinning the back wheels. Build it, then hold a race on the kitchen floor!

  • Level 2 of 5 (easy)
  • About 12 minutes
  • 10 steps, 28 parts
  • Powered by: Pull-back
  • Series: Starter Builds

What you will learn

  • Stored Energy: Energy can be saved up in a spring and let out later.
  • Friction: Friction is the rubbing force that slows things down.
  • Beams & Holes: Beams are the bones of every Technic model.

Build these first

  • Tiny Roller🚗 Tiny Roller: Your very first rolling car — only 13 pieces! (level 1 of 5, about 5 minutes, 6 steps)

Parts you need

  • 1 × Pull-back motor
  • 2 × Axle 8
  • 4 × Red axle-pin
  • 2 × Thin beam 4
  • 2 × Beam 11
  • 6 × Half bush
  • 4 × Small white wheel
  • 4 × Black pin (grippy)
  • 2 × L-beam 3×5
  • 1 × Axle 9

Steps

  1. Find the grey pull-back motor. It is the engine!
  2. Push a long axle through the pull-back motor. This is the back axle.
  3. On each side of the motor, push a red axle-pin into the top hole one step in front of the axle, and hang a thin 4-hole beam on it by its top end, hanging straight down. The end holes of a thin beam are cross-shaped, so they need the axle end of an axle-pin.
  4. Slide an 11-hole beam onto each end of the axle, and join its 2nd hole to the bottom end of the thin beam with a red axle-pin (axle end in the thin beam).
  5. Push the front axle through the last holes of both beams.
  6. Add a half bush to each axle end so the wheels will not rub.
  7. Push on all four wheels.
  8. Push two black pins into each side beam, in the 5th and 7th holes.
  9. Snap an L-beam onto the pins on each side. The short leg points up.
  10. Slide the spoiler bar through the tops of the L-beams and lock it with half bushes.

Play time

Pull the racer back on the floor, then let go. Try a short pull and a long pull — which one goes further?

Build next

  • 🛺 Pull-back Trike: A three-wheeler with a spring engine — twist the front wheel and it drives in circles! (level 2 of 5, about 20 minutes, 9 steps)
  • 🔥 Big-Wheel Dragster: Giant back wheels, tiny front wheels — the same spring pushes this car much further! (level 2 of 5, about 22 minutes, 10 steps)
  • 💨 Gear-Up Speeder: The spring engine sits up high and turns a BIG gear, which spins the wheels faster! (level 2 of 5, about 25 minutes, 11 steps)
  • 🐢 Pull-back Tortoise: Slow but super-strong: a spring car that can climb up a book! (level 2 of 5, about 30 minutes, 12 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)
  • 🐾 Twin-Spring 4×4: Two spring engines — one for the front wheels, one for the back. All four wheels push! (level 3 of 5, about 35 minutes, 16 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)
  • 🕰️ Spring Escapement Clock: A ticking pin-wheel clock powered by the pull-back motor's spring. Tick… tock… tick… (level 4 of 5, about 50 minutes, 22 steps)