Low frequency vibration?

[vegashelipilot]

Just finished replacing wheel bearings and struts on all 4 corners on my father's recently purchased '90 325i (5-speed).

There is still a low frequency vibration that comes on around 15mph and disappears at 25mph (approx.) It is not associated with RPM or load, as it is still there coasting in neutral or with the clutch in.

Any ideas on where I should be looking next would be greatly appreciated!

[tomstin]

My thought is to check if the axle bolts are torqued to the differential correctly and evenly. Pulling those axles you may have disturbed those old CV joints and they may be on their way out.