pabloarc wrote:
I've read several people on different threads mentioned that Neo is harder in erg mode than the KickR, because in the KickR in erg mode if you are in bigger gears you can generate more inertia. Especially for above FTP intervals. If I currently use a KickR in erg mode in small chainring only for my above FTP intervals, would I notice those same workouts to be harder if I do them on a Neo?
If by "harder" you mean that you expend more watts on a Neo than a KICKR, then no, they should be the same. Assume that they are both accurate or both are using an external PM for power match, the rotational inertial is irrelevant in steady state (you are not changing cadence within a fixed gear). The impact would be that the KICKR would need to apply more braking force to overcome the inertia, but it would match the same system input power needed or requested. Imagine it in the extreme. Picture that it has a two ton flywheel. It would take an enormous amount of power to get it moving from rest, but after that, the sucker would just want to spin. However, the brake just needs to apply enough power to overcome the inertia so that you need to apply your target watts to keep the system steady state.
The difference in feel between a system with no inertia versus huge inertia would be what happens during changes. It would take way more braking from the trainer to slow it down and way more power from you to speed it up-- cadence changes without changing gears.
In your example, when you do those intervals that go from recover to >FTP, if you do not change cadence, then both systems only need to apply the same braking force to equal your target watts. However, if you do a spin drill, you would likely spike power more to accelerate the flywheel.