SS good for training? Oh yes, and no mistake.
So I'm all for trying things out and here's *my* evidence, and I know my level of fitness / state of mind at the time.
Using the CVMBC as a benchmark:
Geared bike: about 4:30 (I was v. Unfit)
Rolhoff : 3:20 (after some practice)
SS 36/18: 3:37 (today, very disappointing)
Thing is, I felt fitter and faster than ever today. The 15mph headwind didn't help but I can think it would have hurt me so much anyway.
I burned past quite a few geared bikes on the climbs.
I held my own on the down hills. (touching 45+ mph at parts)
The SS loses out on the not-so-hilly bits where the high gears burned past me.
My thoughts for next few months is for SS for some training and use a 1x9 on the other bike for race pace rides.
SS, at end of day, is a bloody good way to get stronger and fitter. That cannot be denied.