Lego plastic vs carbon fiber vs aluminium vs stainless steel. Lego-compatible axles tested comprehensively. Enjoy!

0:09 Max torque test
4:15 Durability test
5:56 Friction test 1: car and a slope
6:54 Friction test 2: rotating plate
7:51 Noise test
8:44 Insertion test into Lego parts
9:44 Close-up images
10:21 Weight & density comparison
10:53 Price comparison (Nov 2023)
11:14 RESULTS SUMMARY

Carbon fiber axles are made by CaDA Bricks.
https://decadastore.com/products/cada...

Aluminium axles are made by Metal Technic Parts a.k.a. Dark Ice Designs. They also make the metal gears and beams that were used in the max torque test bench.
https://metal-technic-parts.com/colle...

Stainless steel axles were originally sold by Brick Machine Shop on BrickLink (obsolete), later cncgear on EBay (obsolete), and now planned to be sold by Prototype Production.