Inside rear tire wear issue, for the problem solvers out there.

Hi all,

 

Car just failed the ME inspection, some aggressive inside tire wear on both rear tires.

 

Alignment is fine with my winter tires (stock rims), no wear noticed.

 

Thoughts:

 

I did travel with my wagon loaded to the brim (with a roofbox loaded to the brim) for 2200 miles last week - could the extra weight cause the suspension to be lower causing toe (like the similar honda issue)?

 

Could my summer wheel setup (2011 WRX with Dunlop Dirizella DZ101 (235/45/17) be causing the issue?

 

My plan of action is to get some saggy butt spacers, and put a RSB in there while im at it.

 

Thoughts anyone? I plan on alignment when the spacers are installed.

How loaded? That could definitely cause some issues.

Pretty loaded, just enough room to sleep back there, my box is pretty big too. The springs were definately way down, enough that my low beams were too high.

 

Obviously the smart mans move is not to put that much weight in, but do you think saggy butt spacers will help. Even unloaded the back suspension sits lower than the front.

Which tires failed the inspection? Your summers or winters? If its the summers, I'd bet the issue is alignment variation due to the different tire size. You're 20mm wider than stock, so a slight misalignment could result in pretty heavy wear, coupled with a heavy load, and summer tires, they could wear pretty fast.

When you loaded the car up, the rear sagged (as you know) and threw the toe way out.

Which tires failed the inspection? Your summers or winters? If its the summers, I'd bet the issue is alignment variation due to the different tire size. You're 20mm wider than stock, so a slight misalignment could result in pretty heavy wear, coupled with a heavy load, and summer tires, they could wear pretty fast.

 

Interesting info, so i'm guessing as I do most of my miles on my summer setup I should have that aligned, and not worry so much about the winter - especially as there is snow on the road most of the time in CO and wear is pretty non-existent.

 

Or, should I sell the WRX rims and go back to stockers? I do like the way the car looks but its always function>form as a personal preference. Is the 20mm a common issue for wear?

Loaded, you're going to increase camber and likely add negative toe, which would cause the inside wear that you described.

 

Definitely check your alignment settings when you go between tires with difference in size, offset and even type (winter versus HP Summer) where sidewall rigidity can affect toe and camber settings.

 

FWIW, I added the WL KTA124 to enable me to precisely dial-in both camber and toe.

Interesting info, so i'm guessing as I do most of my miles on my summer setup I should have that aligned, and not worry so much about the winter - especially as there is snow on the road most of the time in CO and wear is pretty non-existent.

 

Or, should I sell the WRX rims and go back to stockers? I do like the way the car looks but its always function>form as a personal preference. Is the 20mm a common issue for wear?

 

You can think of the extra width as acting like a lever arm. So properly aligned its not an issue. But if your alignment was a little bit off, it will have more impact on a wider tire. Get an alignment for your summer tires, and I suspect you'll probably be fine.