As I already mentioned in A little history about me, with my first biped I encountered several obstacles, the price of the servomotors and their quality were the biggest determining factors. For my second biped (I already had a job), I decided to go overboard and not to look at the price of the servo motors. I wanted powerful ones, of good quality and that the passage of time and use didn't harm them. I ended up buying the Hitec 5990TG, servo motors with 30Kg/cm of force and titanium gears. I got them at a very good price, with an extraordinarily favorable euro-dollar exchange rate. Even so, the price of the biped had tripled and after its use I detected a new problem, they were powerful and of clearly superior quality to the ones I had before, but they were still "stupid". Finally and for different reasons (among others the exorbitant price of building a biped by hand), I stopped building bipeds and turned to the cars (line-followers, trackers...).