I'm curious why stormtroopers have a gear-like ending to their right upper leg piece, but on the left leg have a diamond shape over their knee.
Is there an in-universe explanation? (Or, if not, an out-of-universe one?)
The Star Wars Visual Dictionary tells us the answer:
The left knee plate is a "Sniper position knee protector plate" and the ridges on the right thigh are "Suit systems power cells."
The Legends entry on Wookieepedia backs this up, citing Star Wars: Imperial Handbook: A Commander's Guide as their source:
- The lower right leg segment contained the suit's axillary power cells.
- The left upper side of the shin armor had a knee protector plate for comfort from a kneeling firing position.
For clarity, the sniper plate on the left knee is attached to the left shin piece. The "gear-like" piece is actually attached to the right thigh piece, not to the shin piece.
It is not specifically for kneeling on, though. In the firing position, the left leg is forward and the right leg is back. Because the left leg is forward, if the plate were not there, you would see a gap between the thigh and the shin plates that would be a weak point.
This is highly hypothetical, so take with a grain of salt.
If you kneel while shooting, you'll kneel on the knee at the same side of your dominant hand. To have better balance.
But that would require them to be all left handed and never to cover something on their left.
But it could be as well just be an artistic choice and backwards rationalization ( see pictures )
I have two theories to why the armour is asymmetrical.
Storm Troopers would shoot with their right knee to the ground.The pad was designed to protect the left knee from blaster fire when in shooting position.
The lack of a protection pad on the right knee would make getting into shooting position much easier and quicker.