Let me start by explaining a few features on this washer---perhaps this may allay any concerns (or make better sense).
This washer has something called: "True Balance".
True Balance involves using a *Balance Ring* located at the front of the tub assy and is filled with oil & steel balls.
An *inertia sensor* is mounted at the top of the tub assy as well.
The spin profile will be as follows:
0 to 400 rpm : Tub begins ramp-up to spin.
At this time--the entire washer usually has low-resonance shake/wobble/spring noise/sound of air.
As the tub reaches 400 rpm---the steel balls within the Balance Ring begin to *separate* from
each other and will move to a position--which will stabilize the spin tub at rpms beyond 400rpm.
The amount or degree of stability will be dependent on the *quality* of the floor.
Obviously--on a concrete floor---the washer will be exceptionally smooth during spin.
On wood floors--especially less-than-stout wood flooring---the washer will be as stable as can be made
possible (slight continuous vibration).
400 to 1100 rpm: Smoothest possible spin performance occurs at these speeds.
400 to 0 rpm: On ramp-down---there will be a slight rattle/rattle/rattle/shake before the tub comes to a complete
The Inertia Sensor "tells" the MAIN BOARD the amount/degree of shaking of the TUB ASSY.
The MAIN BOARD is "timing" the amount of time it takes for the tub to stabilize before allowing the motor to "go to full throttle".
If it takes the tub too long to stabilize---the MAIN BOARD will "abort" the spin program.
Another attempt will be made after the tub tumbles laundry to redistribute the laundry load/weight.
LG washers *not* equipped with True Balance---will exhibit the following on WOOD FLOORS:
0 to 500 : Tub begins to spin. Pronounced shaking of the tub & washer body is noticed along with typical
noises from a rotating assy.
550 rpm: Imbalance is at it's WORST/MOST SEVERE
600 to 750 rpm: Tub & washer body continue to shake but *less so* as rpm speed moves past 550 rpm.
750 rpm: At this rpm---the degree of shake/noise is half-as-severe as it was at 550rpm.
Above 750 rpm: Again the severity of the shake/wobble/noise somewhat diminishes and the washer continues it's
spin cycle with a moderate degree of continuous resonance. This varies depending upon the type
and size of laundry load.
Source: LG WM2101HW - Wash Drum Hitting Washer Door