Spring Car – Wind-up Mechanism - 4x4

Hello everyone, here is my latest creation: a small wind-up car, 4-wheel drive, in a minimalist, easy-to-assemble version. It can be used for educational purposes (mechanics, math, etc.) or simply as a toy. It will allow you to understand the operating principles of a wind-up car without risk of error (as everything is detachable). It is also a first step towards my more sophisticated models (feel free to check them out: https://makerworld.com/en/models/733706-hot-rod-v8-spring-engine#profileId-665458 ).

No glue, no purchased parts, no tools (Even the 10mm wrench is 3D printed). Assembly is simple and can be done by children aged 8/9 and up. Once assembled, it can be handled by children aged 4 and up. (See video)

These cars are tested and approved by my own children!!!

This small car is designed to be easily assembled and disassembled to allow changing the transmission (3 transmissions available: short – standard – long), to switch the drive to front wheels only, rear wheels only, or all 4 wheels. This type of assembly also allows you to change any broken part.

For better grip and to allow assembly, it is necessary to make the tires from TPU but TPU for AMS, PLA, and TPU 64D will not work because you won't be able to fit them onto the rims. I use TPU 60A but you can go up to 85A. If you do not have the ability to print TPU, you can make the tires with small rubber bands, O-rings, or bicycle inner tubes (the rim's groove bottom has a Ø of 27.5mm).

I have created a detailed assembly guide to assist you during assembly. At the end of this guide, you will find all the necessary data for developing math exercises related to this wind-up car.

HAVE FUN!!!

Updated on 16/09/2025: increased functional clearances on all axes (from 0.3mm to 0.45mm clearance)

New model with a body : https://makerworld.com/en/models/2238342-wind-up-car-hot-rod-wind-up-mechanism#profileId-2436133

(During assembly, keep an eye on small children: there are many small parts that pose a choking hazard.)