Is it possible that a clutched rear derailleur actually saves Watts? Now before you get the pitch forks I was having a discussion about this with someone who knows way more than me about friction. The thought process was the extra tension may cause a small loss but by calming any extra chain movement it could be a net zero or possibly better. Now I have been running shimanos RX 805 clutched di2 rear derailleur on a 1x setup but with my new bike I'm returning to 2x ( to hilly were I live and the races I want to do) and considering keeping the clutched derailleur. Now the RX has a switch to turn it off but if it's a net zero or possibly a small gain why not leave it turned on. Now I have tried to find any loss on the trainer but can't. Ie to small or doesn't exist.

Discuss........