[10intheCrunch]

Ummmm...I believe if you calibrate your Victors, it will work linearly.

PWMs are pulsed voltages, so the farther from 127 you are, the more often the voltage is pulsed. At 254, the voltage is a solid 12V, and your motors will work as hard as they can.

If you are thinking in terms of when the *motors* reach full speed etc, no one can tell you. That all is going to depend on the load they are under, conditions around them etc. Your motors will work faster when the bot is on blocks than on the carpet...the only thing you really know is the voltage that is output to them (or average voltage, as its still pulsed at 12V).

Hope I didn't misunderstand your question...