Tire balance go do itHi, all! My 2010 Outback "Gus" (short for Carsophagus), with a 6-spd stickshift, driven 45K, got new Firestone tires installed... mmm... at about 25k. And I've kept to the scheduled rotations. I'm not sure how concerned I should be by the new, subtle but noticeable shaking whenever I'm between about 50 & 55 MPH. Sorry I'll be going on at length, but I want to detail all unusual events here.
Just a few days before leaving Minnesota, the RF tire sprang a slow leak. I examined the tire, and nothing was visibly stuck there... so I squeezed in a pint of Slime, and went on my way uneventfully, with mostly local driving.
Then I mounted Gus on an auto trailer (yes, all 4 wheels off-ground) behind a U-Haul truck, and hauled off to New Mexico. Safe speeds, no problems, just a discovery that backing up with a big trailer is truly a fine art.
As soon as I arrived in NM and dismounted Gus, I discovered the shaking syndrome, which was much more pronounced than it is now, at freeway speeds. Immediately I suspected the one tire fulla foreign matter, and when the tire was removed, I was startled to see how much green liquid was freely sloshing around inside the thing. I decided to err on the side of caution & replaced the tire, keeping the slimed one for a spare. They rotated & balanced the wheels for me too.
But as I said the car still vibrates, only a little bit, but just enough to know it's not my imagination, and only between 50-55. What do y'all think? Could the auto trailer have messed with the alignment? (U-Haul staff mounted & unmounted.) Might a front-end alignment help? Thanks for your attention!