Uneven tire wear - why?

I don’t know much about tires other than they are round. I noticed one of my front tire is wearing uneven. Seems that every ~5 inches one of the “notches” (for a lack of the correct word) is about 1/8in higher than the preceding 4.

The inside of the tire seems to wear OK.

I put in new shocks abut 10k miles ago and replaced ball joints. That’s all besides an alignment after the work.

What can most likely cause this type of uneven wear?

ScreenHunter_466 Jun. 28 14.16

Why not show the tire to a good tire shop and see what they say .
I will Bat Signal the resident tire expert for you . @CapriRacer do you want to wade in ?

Too much toe in can cause this, as can the tendency to corner harder to the direction opposite the tire as well as the tire’s structural design and build variations. Additionally, worn bushings allowing deflection to alter the alignment. Also can’t eliminate build variation or damage of the frame/chassis structure.

Normally I’d say a bad shock/strut but you’ve covered that. You might want to have the tire’s balance checked. Beyond that I’d suspect ball joints, bushings, or something similar in the front suspension.

I have two initial thoughts, the first is that you run the tire too low. The tires should be at least the pressure recommended on the placard on your door post or glove box. Often people will pump the tire just to this pressure and not check it again for three to six months. Tires loose about 1 psi per month on average.

Unless you check your tire pressure at least once a month, I would recommend going 2 to 3 psi above the recommended pressure so that the tires will not be under inflated if checked every quarter and only a little underinflated if checked semi-annually.

Second thought is that the alignment may be off a little, either a little too much toe-in or too much camber. Both of these are aggravated by low tire pressure so step one is to check those pressures. You can also rotate the tires to the back of the vehicle where most of the tire wear is in the center of the tire. That will help even out the wear pattern.

How many miles were these tires used with the old shocks?

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First, many things can contribute to the type of wear seen here. Among those things would be bad shocks and bad ball joints - and even though you fixed both of those and the wear may have not have been apparent then, the wear continues , but at a slower rate.

So I suggest when you replace the tires that you get an alignment, just to make sure

Approximately 20k miles

That is precisely why I inspected the ball joints and struts and replaced them on both fronts. Except the damage was significantly less at the time. Approximately 5k miles ago

I will replace the tire and get another alignment done. Thanks for everyone for their input.

A wear pattern gets worse over time - and it gets worse faster, the longer it continues. Correcting the problem that caused the wear doesn’t change that the wear is still there. New wear goes on top of what is already there.
Only replacing the tires will fix the wear.

Put another way: Any uneven wear on a tire will continue unless you over compensate.