Here’s a fun contraption to build out of LEGO® bricks – make a fun little car that is powered by a rubber band! This rubber band powered LEGO® car will zoom across the floor for 20 feet or more.
Building this car is a great engineering project that demonstrates the power of potential and kinetic energy. It would be fun to build these with a LEGO® club or STEM class and see whose car travels the farthest!
Before I get started with the instructions on this project, I want to tell you that there are many ways to build this car once you understand the concept. I’m including instructions since I know that is helpful, but kids can make their cars look the way they want them to.
The basic design involves a pin that sticks up at the front of the car. Then a second pin is attached to the back axle. To make the car work, you’ll stretch a rubber band around both pins and then turn the back wheels to wind the rubber band around the back axle.
Let go, and the car will zoom away!
We had fun building a little jump for our car out of sloped building blocks (the Melissa and Doug unit blocks). The car really had enough power to go off the jump!
How to Build a Rubber Band Powered LEGO® Car
Step 1: Attach two 1 x 12 Technic bricks to a 6 x 6 plate. Technic bricks are the ones that have holes in them. You’ll need the holes for inserting the axles.
Step 2: Gather the pieces shown for building the back axle.
The black axles are 6 studs long.
The black connector is a Technic axle and pin connector #2. The piece actually has a 2 printed on it. (Link goes to this part on Brick Link.)
Step 3: Slide the axles through the last hole in each Technic brick and into the Technic axle and pin connector. Add a yellow 1/2 bush on either side of the connector. Put a red bush on each axle on the outside of the Technic bricks.
Insert the gray pin into the axle and pin connector.
Step 4: Add a 1 x 6 brick on both sides of the car. Find two 1 x 8 plates.
Step 5: Attach one 1 x 8 plate to each side as shown. Then place a 1x 4 plate on top of a 1 x 6 brick.
Step 6: Attach the brick and the 1 x 4 plate to the back of the car.
Then find two 2 x 4 bricks.
Step 7: Attach the two 2 x 4 bricks inside the car. Add two 1 x 2 blue tiles with a handle for decoration. Then find the pieces shown for building the front axle.
We found that the car traveled the farthest with big tires on the back and narrow tires on the front, but you can use any four wheels to make this car work.
The black axles are 4 studs long. The light gray piece is a Technic axle connector 3L (3 studs long).
Step 8: Slide the axles through the front holes on the Technic bricks, and insert them into the Technic connector. Place a light gray bush (1/2) on each axle outside the Technic bricks.
Step 9: Attach the front wheels. Add two 2 x 6 plates to the front of the car. Then find two 2 x 4 plates, an airscoop, and a 2 x 2 tile with a pin.
Step 10: Attach the plates, airscoop, and tile with pin to the front of the car. Build a spoiler on the back. Attach a 2 x 6 dark gray plate. Then add a 2 x 10 plate with a 2 x 2 slope on each end.
Find a good rubber band. You may want to test several and see how they affect the performance of the car.
Now it’s time to wind up your car and try it out! Stretch the rubber band from the front pin to the back.
Then turn the wheels backwards to wind the rubber band around the back axle.
Need more LEGO® project ideas?
- Build a LEGO Safe with a Working Lock and Key
- Build a LEGO Disc Launcher
- Create an Epic LEGO Marble Run
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