Replace stock bearings by these high quality ABEC-3 bearings with much higher tolerance and smoothness and feel a much difference in response.
Specifications:
Bearing 128ZZ (8x12x3.5mm)
Quantity: 1 piece
If it doesn't specify which ABEC rating, it's likely that's it's ABEC-1. ABEC-3 bearings are much tighter in tolerance than ABEC-1 bearings, thus provide much higher accuracy and smoothness.