I am similar weight, ftp, and group ride experiences. After getting back into cycling in 2016, my first big event was 5 mountain passes with 15,000’ of climbing. My W/kg was maybe 2.8 at the time, so that meant spending 8 hours climbing on 5 sustained climbs. If your weight is fixed, then you need a lot of muscle/aerobic endurance. If you can drop weight then its like getting free watts. If you can drop weight and grow ftp, win win!
As already stated, if you want to get faster on climbs then focus all of your energy on:
- losing weight
- growing ftp
For sustained climbs you also need to focus on muscle endurance. There are TR plans for that.
I’ve played around with gearing and haven’t found value in trying to optimize muscle recruitment (Shane Miller video). Regarding little vs big chainring, all I’ve been able to conclude is that just like on the road, the little chainring provides a torque multiplier.
What does that mean? It means that less torque (force on pedals) is required to cover changes in trainer resistance (going from 100W to 200W in erg), or when you are riding outside and need a burst of power to bridge a small gap or deal with a short kick up in grade on the road.
I’m not a fan of using small chainring on my Kickr in Erg mode, for me it feels easier because less torque is required to cover both small and large changes in resistance. I feel like the “flywheel inertia” narrative is missing a) the impact of gearing on pedal force / torque, and b) ignoring that in Erg mode the trainer is a system with both a braking system AND spinning flywheel. You can’t cherry pick and focus on the spinning flywheel, and ignore the impact of Erg braking and how that translates into required pedal force thru all the gearing (both trainer gearing and your bike’s gearing).
My best long climbs have come as a result of focusing on the fundamentals:
- muscle endurance via longer and longer intervals at sweet spot and threshold
- aerobic endurance
- increasing cadence to shift burden from muscular / anaerobic energy systems, to aerobic energy systems
Hope that helps.