Undergearing Motor

[DaveG28]

Does doing this do any harm or just affect performance?

Reason I ask is using a Speed Passion V3 5.5 last week I went from a 10.4 FDR to 11 FDR and it had a bigger effect than I expected, really seemed to lose the sweet spot, didn't seem to have any extra acceleration and lost more top end than I'd expect!?

Anyway, as it happens I don't find that a bad thing as on most indoor tracks I'd probably want this, but don't want to use it as a tuning aid if I'm also damaging the motor in anyway?