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Outside rear tire wear problems

I’m getting bad outside tire wear on both sides in the REAR. I’ve replaced all of the suspension components, shocks, struts, control arm and panhard bar. What else could be causing it?

I’d suspect the alignment first. Then I’d check the driving styles of everyone who drives this vehicle to see how fast they’re taking corners.

Is there some reason you’re throwing parts at it rather than having it checked by an expert?

Too much rear camber, and it could have been made worse if the new struts included new springs that were taller or stiffer than the originals. How many miles on those tires and have they always been on the rear?
If you have a wear problem with new tires because of alignment or parts, you might not notice the uneven wear and you correct the problem but the uneven wear doesn’t reverse itself . There may be only 2/32 difference between the rest of the tire and that edge.

If the specs for alignment for your 4 runner are maximized for a fully loaded or tow vehicle and you are running around empty all the time, that is the likely result.

Truck based SUVs have a wider load range than a car, or even car based SUVS and require greater compromises to accommodate that That is why they don’t make great commuter or mall hopper vehicles.

We need to know the tire size. We also need to know what tire size is listed on the vehicle tire placard - which should be on the driver’s door frame, but if not, try the glove box or the fuel filler door.

How about tire pressures?

Going out on a limb, I’m guessing these used to be the front tires that were on there for a very long time, then rotated to the rear relatively recently. Steer tires tend to wear the shoulders where drive tires tend to wear the center - and if the front camber is bad, the wear won’t be even. (I think a 4 Runner has a solid rear axle, so I doubt that there is a camber problem in the rear.)

Oh, and the tire in the photo shows it is worn to the wear bars in the shoulder, but overall the tire doesn’t appear that much different across the tread (except for the outermost shoulder!)

I can’t really tell from the pic how the insides look, proper air pressure but both shoulders of the tires seemed prematurely toast on my car. BF Goodrich Long Trail TA

That tire appears to be flat-out worn out and possibly was run underinflated a bit. Not only are the shoulders worn, but it appears that the center is down to wear bars.

How many miles have those tires been on road? How old are the tires? Can you read the DOT (Department of Transportation) numbers that include the week/year of manufacture at the end of the DOT number…
Example: 3214 (32nd week of 2014).

FYI (for your information), it’s fortunate for you that @CapriRacer is contributing. He is a tire engineer and an expert. He has a website.

Here’s DOT number information.

what year is this 4-runner?

LOL, when I was young we used to say that if your tires were wearing evenly you weren’t cornering fast enough.


I’m not cornering hard, I mostly drive in rush hour traffic.

4Runner is a 2002.

Tire size is 265/70-16 tire placard is 225/75-15 but I think the 16" is an option for the limited that year.

Pressures may have been a little low, I don’t check that often but when I check was around 32psi.

These may have been on the front for 5-6K, total miles is around 15K. Tires are around a year old. These are not the first set to wear like this and I really don’t think its the front, since you can measure tread wear on the rear after 5K on new tires. Both sides wear like this. Rear axle is solid.

Tire is good except for the shoulder.

No it is not good. You need four new tires and a good alignment. You may have the optional 16 inch wheels but a tire shop will know for sure but 265 seems to wide.

Tirerack shows 265/70-16 to be an OEM optional size, with 225/75-15 to be OEM standard.

The exploded view drawing also confirms the OP’s statement that it’s a solid rear axle.

The only thing I can think of that might exacerbate outside edge wear in the rear MIGHT be tired shocks. If the body is leaning excessively in corners, it might cause the weight to load a bit more onto the outer edge of the outside rear tire. As the tires’ sidewalls flex, a solid axle does in fact lean relative to the road.

Hey, the shocks are what, 15 years old? It can’t hurt to change them!

According to OP shocks are new

Oops. In that case, I’d consider it just slight wear variation perhaps from a bit low tire pressure. The rest of the tread does actually look past its prime… and almost to the wear bars.

I expect there’s an alignment problem. If all this wear occurred w/the tire on the rear, the wheel must be slightly tilted out at the top, the top sticks out further than the bottom in other words. A bubble level with some spacers against the top and bottom of the rim might demonstrate this tilt if you want to become an amateur scientist. After installing new suspension parts, the recommendation here is usually to also get the alignment refreshed. It’s possible there are problems that can’t be corrected just by an alignment of course, but an alignment would at least show the cause of the abnormal wear pattern. From what I can tell, those tires aren’t safe to continue to drive on.

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Like CapriRacer, I also wondered if the tires had been on the front for a while and whether or not the issue started there.

Maybe it’s the picture, but the tread seems a bit skimpy for a tire that only has 15k miles on it.

I realize it’s a solid rear axle but just for grins I wonder what a tape measure would show if measurements were taken on both the front and rear sides of the rear tires just to make sure the toe is identical.
Just wondering about the possibility (rare it may be…) of a tweaked rear axle housing.

Or an axle housing squirming in the mounts.

It is possible to bend the rear axle housing causing a toe-in or toe-out condition that will burn up tires prematurely. Place the truck on an alignment rack and take the readings.

Five years ago I had a Lexus GX470 (similar chassis) with the rear toe value off on the right rear, the owner stated that they only “brushed” against a highway barrier. It turned into an insurance claim, replacing the rear axle housing corrected the problem. Check your alignment values.

If tire pressure was the issue, you’d have excessive wear on both edges of the tire, not just one outer edge.

I’m sticking with my original answer. It’s an alignment problem or a driving problem (because the OP might be in denial).

I’d still like to know why the OP has been throwing parts at this problem instead of having an alignment done.

Except the OP isn’t telling us about that time he (or previous owner) went 4X4ing and hit the pumpkin on that rock and bent the rear housing.

…or maybe the OP bought this vehicle used without knowing it’s full history?

As has been pointed out, 15K is horrible wear. That leads me to believe that the tires are wearing fast because the vehicle is driven around the city and very little highway. (There’s a comment about rush hour traffic) THAT could result in the wear pattern.

So I don’t think this is going to be fixed by replacing parts. It’s possible that there is too much toe in, so an alignment is in order.

The only other suggestion I have is to drive more gently - especially in the corners - and more especially, exiting those corners.

when did you notice the worn tires? when you are long past the wear bars i would replace them. if you think there is an alignment or shock issue than throw on some used tires.