2004 Volvo S80 VIBRATIONS OVER 60 MPH

I m also having the same problem wih my S80 T6 2004 55000KM. All tires are brand new and the vibration occur when going up hill @ 80Km/h with rpm stuck at 1500 and it wont go up. Please help.

Just donated $3 to help the cause. And get an answers as my 2002 Volvo S80 has brand new wheels and tires and still has the skakes at 40mph or higher, with a bit more under a load up a hill, etc. We here told we had bent rims, and the tires were carryover from when we bought the car used. It does seem to have gotten progressively worse over the past 6 mths, thus the new tires and rims thinking that would solve the issue. The car does travel mostly straight when we take our hand off the sterring wheel so we presume the alignment is OK. We thought maybe a bent wheel spindle but would that affect at all speeds. Plus the "under a load" phenomenom is puzzling. Other ideas that we could check? Thanks all.