So, here we go. The Avio AT Gear Drive Mk2, Stealth Edition, featuring, you guessed it, HERRINGBONE GEARS!. 
If you don’t want to read the rest of this post, TLDR: they rock. they are so much quieter, easier to assemble, with fewer parts needed. (Read on for more.) Oh, and the gear ratio has been updated to 13:51 i.e. (3.92:1)
First, let’s show some pictures. These are taken in a rush, so don’t judge me, i was really excited to put the whole thing together.
Quieter!
If you can see from the pics, 2 different spur materials were tested, the traditional POM and ALU 7075. People were worried of the strength of POM, so we decided to go for a beefier option. Now, i know what you’re thinking, it’s gonna be LOUD AF. → Far from it. It’s MUCH quieter than my spur gear design, with a different sound pitch compared to the POM herringbone gears, but probably the same sound level (dB) between the 2. I’ve yet to measure this and will get back with some quantitative numbers when i’m done with testing.
Easier to assemble!
Assembly is also made easier. Herringbone gears are inherently self aligning - that means no more Loctite 638 to attach the pinion to the spur! easily swap them out (literally slide the pinion out from the shaft) for different pinions to change the gear ratios quickly! (when we produce them!)
Fewer parts!
Well, you don’t need loctite 638 anymore, plus, the bearing has been changed to a thinner bearing that better adapts onto the Kahua trucks. That means you don’t need 2 bearings anymore, a single bearing on the inner part of the truck is all that is required!
Lighter!
The gears have also been slightly redesigned to be lighter (The POM version at least) with cutouts, but not affecting strength of the gear.
Stronger!
Aluminium Spur gears provide an increase in strength while keeping it lighter than the previous design!
Quieter!!
Did I mention how much quieter it is? I’ll upload videos soon, but from initial testing, it’s definitely something to be excited about. 
What now?