Hey, could warped rotors cause a vibration at 50-55 mph but no where else? It's the only thing I can think of on my jeep. Checked the hubs, ball joints, shocks and brand new tires.
Vibration in seat or steering wheel?
I would pull calipers and check for free movement of guide pins and ensure the brake pads move freely in the abutments.
A dragging pad can heat the rotor.
Also, some claim improper wheel torque will warp a rotor.
While wheels are off ( aluminum?)
Check for corrosion across mounting surface and clean as necessary.
Would get worse the farther you drive.
Had a ranger a few months back, brake cable was causing shoes to drag, more i drove the worse it got. One drum was way hotter than the other. Replaced cable and vibration was gone.