Flywheel shudder on return?

[SirWired]

At the gym I'm using while on travel, two of the 3 D's have a flywheel shudder on return, and the shudder is more intense at shorter splits. Since this gym seems to have no clue about C2 maint., I'm going to have to spell out, using very small words, what's wrong.

I'm thinking maybe the flywheel clutch/bearing, but none of these machines have over 10M, and are only a couple years old... that seems a bit early for the bearing to give out.

(They have other problems, (the flywheel screens are filthy, one stiff chain, etc.) but this is the one I can't give a concrete recommendation on yet.)

[Cyclist2]

I would guess its unbalanced due the dust and crud from lack of maintenance. The wheel collects dust, too. I'll bet a good cleaning and lubricating will solve it.