Tire Wear

[HowAboutThis]

Do you slow down for the curves? Cornering will wear the edge of the tire more than the center, so if you (or whoever drives the subie) likes to chuck the car around corners then that might be part of it

No we're boring drivers. We both coast to stoplights and things like that.

 

[HowAboutThis]

How often do you rotate them?

Every 6-7.5k with oil change.

 

[HowAboutThis]

I just find it odd it's like a quarter to half inch strip that's wearing, on all 4 tires, on both the inner and outer edge. And has done it since new. And an alignment said it was in spec a while back. That's why I'm wondering if it's the crowned roads and the tires rub on the inner ol and outer edge of the crowns. Maybe need to have alignment checked again but also don't just want to throw $125 at it for no reason like last time since it's doing the same thing.

 

[krzyss]

It sounds like typical example of low pressure.
What is OE size? Do you have the same now?
What do you have in your car? Any luggage, ballast or an anchor?

Krzyś

 

[Langanobob]

Just clutching at straws, it seems like the softer compound they use for the sidewalls bled down into the edges of the tread during manufacturing. I don’t know much about tire making but I know there is someone here who does, maybe he wil chime in.

 

[CapriRacer]

First, my experience is that inflation pressure doesn't have as much effect on evenness of wear in steel belted radial tires compared to other things like position on the vehicle. Bias tires were more sensitive, which is where that myth came from. It's just not as true for modern tires.

So with regard to the OP's situation, the general advice is that this type of wear comes from lots of cornering - hilly terrain or city driving. But that doesn't seem to be the case for the OP's.

Grasping at straws, I am aware that suspensions are compromises and that you can either have one that doesn't change camber or doesn't change track width (the width between the contact patches), but you can't have both. The third possibility is neither. So I wonder if that Subaru's suspension is one where the compromise is on varying camber and not varying track width. That might explain the two sided wear.

If that's the case, unless the OP wants to rearrange the suspension pickup points - which involves redesigning things, then welding - there isn't anything to be done.

 

[HowAboutThis]

It sounds like typical example of low pressure.
What is OE size? Do you have the same now?
What do you have in your car? Any luggage, ballast or an anchor?

Krzyś

Everything is OE standard sized and such. 2 car seats and a bin with extra oil, jumper cables, etc. 90% of the time is has probably 250 pounds in it, which includes the weight of humans. I check air pressure a couple of times per month and if it's nearing 32 I bump back up to 35.

 

[HowAboutThis]

Just clutching at straws, it seems like the softer compound they use for the sidewalls bled down into the edges of the tread during manufacturing. I don’t know much about tire making but I know there is someone here who does, maybe he wil chime in.

I doubt this as the OE Yokos had the same wear pattern as this set of Michelin's. If I never checked air pressure and was driving low air all the time, I'd assume that was the issue. But since we commute 70+ miles each day (in opposite directions of the interstate) I religiously stay on top of visual checks of fluids and tire pressure at least twice per month. And they don't deviate much (a pound or two up or down as temps change based on the temp when I last filled them). Someone mentioned AWD vehicles doing this to tires so maybe it's common if you own a Subaru?

 

[HowAboutThis]

First, my experience is that inflation pressure doesn't have as much effect on evenness of wear in steel belted radial tires compared to other things like position on the vehicle. Bias tires were more sensitive, which is where that myth came from. It's just not as true for modern tires.

So with regard to the OP's situation, the general advice is that this type of wear comes from lots of cornering - hilly terrain or city driving. But that doesn't seem to be the case for the OP's.

Grasping at straws, I am aware that suspensions are compromises and that you can either have one that doesn't change camber or doesn't change track width (the width between the contact patches), but you can't have both. The third possibility is neither. So I wonder if that Subaru's suspension is one where the compromise is on varying camber and not varying track width. That might explain the two sided wear.

If that's the case, unless the OP wants to rearrange the suspension pickup points - which involves redesigning things, then welding - there isn't anything to be done.

So you're kind of saying, "it might be a Subaru thing"? Someone else mentioned their Outback wears this way, too, I believe. The original Yokos had that rounded edge look (see the picture I posted later because I didn't see the first picture was rejected due to file size) and I replaced at about 70K miles with 4/32nds everywhere except on those two inner and outer areas.

Just seems weird to wear both edges all the way around.

I suppose it could be the fronts are wearing the outer edges and the rear are wearing the inner edges so when I rotate I get a nice even both edges worn...?

 

[dumkid]

could be something to do with factory alignment or suspension geometry, like Capri racer said