[WattDeFalk]

Hi, 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!

 

[spigatelli]

I bet one of the front wheels is still slightly out of balance.

 

[subiesailor]

Hi, 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!

Tire balance go do it

 

[rasterman]

Subarus are very sensitive to wheel balance, and lots of garages have lazy low-paid techs doing the balance jobs. Get the balance re-done.

 

[SubaruCop]

I can tell you that it's probably not the wheel balance. It's the slime causing the shimmy in the tire. I had experience with slime and while it did its job, it caused serious vibration in the front on my hyundai at the time. Many people don't know that shops will not touch tires with slime, some many try to rebalanced the tire, but in my experience they won't even do that. The tire us essentially ruined after slime is installed. The tire will hold up but that's about it. The vibration you are feeling is because the slime moves around in the tire and causes it to be out if balance, even if you rebalanced the tire, keep in mind that slime is a liquid and will constantly move. As the car sits, the slime will collect at the lowest point in the tire and will take a little bit on each drive to distribute it. Hope this helps

 

[subiesailor]

I can tell you that it's probably not the wheel balance. It's the slime causing the shimmie in the tire. I had experience with slime and while it did its job, it caused serious vibration in the front on my hyundai at the time. Many people don't know that shops will not touch tires with slime, some many try to rebalanced the tire, but in my experience they won't even do that. The tire us essentially ruined after slime is installed. The tire will hold up but that's about it. The vibration you are feeling is because the slime moves around in the tire and causes it to be out if balance, even if you rebalanced the tire, keep in mind that slime is a liquid and will constantly move. As the car sits, the slime will collect at the lowest point in the tire and will take a little bit on each drive to distribute it. Hope this helps

My understanding of this product is that it coats the inside of the tire filling any holes and then sets ie dries. That is why you need to run the car shortly after putting it in the tire. Once it sets it should not be moving around. Get the tires balanced.

Also curbing a tire hard can cause a wobble ie vibration that may or may not gradually go away. The continentals I had on the 2010 were horrid about wobbles after being curbed.

Towing a trailer has nothing to do with a wobbly out of balance tire.

 

[tdelker]

Except he just got a new tire to replace the slimed one already.

Which begs the question, how well matched is the new tire to the old tires? The circumference much be very close or you get torque bind.

Sounds like out of balance, but you just had the tires rebalanced. You could bring it back to the same place and say it seems like they are out and ask them to check to finally rule that out.

Inspect the ball joints, lower control arms, tire rods, axles.

 

[subiesailor]

Except he just got a new tire to replace the slimed one already.

Which begs the question, how well matched is the new tire to the old tires? The circumference much be very close or you get torque bind.

Sounds like out of balance, but you just had the tires rebalanced. You could bring it back to the same place and say it seems like they are out and ask them to check to finally rule that out.

Inspect the ball joints, lower control arms, tire rods, axles.

Which case with our VW the last set of Michlins we put on it - I went through three tires before they found 4 tires that were round and didn't shake the VW like a wet dog. Possible the tire they put on it is not right - or one of your other tires needs to be balanced. If they moved the rear tires to the front when you had the new tire put on - you still might need the tires balanced given rear tires can be off some and not cause issue but once moved to the front you might get a nice hand massage at the steering wheel.