How much energy do LEGO Technic gears lose to friction? So, I recently watched a video by the Brick Experiment Channel about building a 1 Googol:1 reduction gearbox, which at the time of writing this question, is at #44 on Youtube Trending. At the end of the video, it makes the claim that the final gear will rotate once every 10^93 years. This seems unlikely to me; it seems much more likely that energy losses due to friction along the mass of gears will reduce the amount of energy it's receiving to 0, so it will never spin on it axis, at least as a result of this machine.
However, I'm left wondering where exactly this in the contraption energy is lost, and how much of it is lost to heat and how much is lost to noise. How efficient are LEGO Technic gears, when mounted on their standard X-shaped axles through the holes in standard LEGO Technic bricks?
Nice find. First of all, it is interesting to see the various techniques they use. 

The short answer to your question would be: It doesn't matter. Each gear, axle and all other components bend, stretch and absorb energy. This means that even for normal large LEGO Technic sets, such as the 42055, you have to build carefully and avoid too much pressure to reduce friction.

When it comes to Googol, it will take years to move most of the gears above their tolerance of, say, 0.1 mm. This is why they put the motor to the beginning of each section to show that it works in principle.

So, starting the whole thing will increase tension and some eruptive movements of the gears in the middle will follow. But the gears further down the line will never move.