what exactly do you want to know?
All they really do is send the power to the wheels instead of using driveshafts.
You would adjust the amount of teeth one has to change the amount of front/rear drive eg. a touring car has something like a 2% front overdrive, meaning it spins 2% faster than the rear wheels (for example) if you change that, you change the way the car would handle and respond to different changes.
Im sure somebody willing to explain that would do better than me, but thats the jist of it.
Car-less (Velox V10 or 733) // RB T10.5"+" (JB Modified) // Bluebird BMS-990DMG (St) & BMS-631 (T/B) // ATS 16% // Capricorn Wheels // Protoform
"70% of the time, it works ALL the time"