[thstone]

Originally Posted by san rensho

They are wrong. In a double clutch heel and toe downshift, which is what I think they are talking about, you put the clutch in, shift to neutral, let the clutch out and with the clutch out, blip the throttle to rev match and then quickly put the clutch back in and downshift.

This is the preferred way to downshift as it puts the least amount of strain on the synchros and leads to maximum gear box life. (Its actually the only way to shift old Alfa Romeos because the synchros come worn from the factory and if you don't double clutch, it will just grind and not go into gear). I suppose with the clutch out there is less wear on the TOB, but I would guess the difference is minimal. What double clutching does is save the gear box, primarily.

On our cars, the synchros are so robust that double clutching is almost overkill, but rev matching definitely helps preserve the gear box and really cuts down on clutch wear.

+1 ^^ What he said. ^^