Shimmy at 30, not me ,my suv

Anybody have any suggestions on what would cause the steering wheel to shimmy/quiver at approx. 30 MPH on my 03 Dodge Durango. Had a 4-wheel alignment done last year and seems to slowly drift to right, but that could be due to road crowning.Thanks

Sounds as if you have a belt in your tire that is going bad.

Thanks for the tip

Tires can be checked for internal defects on a “road force balancing” capable machine. That spins the tire while applying a simulated road force via a spinning drum pressed against the tread. It’ll also be checking the balance.

The drifting may or may not be related. If you have a defective tire it could have more rolling resistance than the others due to the defect and be causing the drift.