No such thing as cheap retract servos. They have to be very strong to lift that wheel up, there isn't much leverage there, and they move slower that a regular servo to give them even more torque, plus it makes the gear look more realistic.
I used to work as a machinist. Back then I designed my own retracts that incorporated an over-center spring. When properly adjusted, there was hardly any strength required to raise or lower them, and they work easily with a standard servo. Alas, I no longer have access to my CNC machine, and I only have two sets left (they were so popluar I sold them faster than I could make them), and I won't part with either one!
PS As far as the graphics go... Yea, I'm a guru
