If the total overall throw is ~7". The first 2"- 2 1/2" are the dead inches where the pedal does not return to the top as mentioned before. This leaves the pedal at about the 4 1/2" - 5" mark off the floor. The clutch works almost immediately when pressed from the 4 1/2" - 5" mark. It's working range is about 2 1/2" - 3". To answer your question, It starts to engage about 2" off the floor.