What causes this tire wear pattern

Last year when I rotated tires I saw a strange wear pattern on my fronts. The inside of the front tires had some scalloping(?). I knew that my struts were blown and attributed this odd wear to the bad struts. I replaced the struts and had the car realigned, 7° caster, 3° camber and factory toe(for a 318ti). This year I took my front wheels off and I'm greeted by the same pattern, on wheels that didn't look like this 5000 miles ago. I was in there to install new tie rods, could bad tie rods lead to this wear? When I get it aligned after this tie rod install I may have some of my camber removed but I've not seen it wear tires in this specific pattern before.

Can you take a picture of the whole tread surface? It looks like "heel/toe irregular wear" on the inside shoulder, but there might be more that can be seen from the whole tread width.

Could be tie rods, ball joints, wheel bearings, or anything that allows the wheel to flutter around ever so slightly. You already took care of the struts - that's can be a common instigator.

Some tires (read: cheap ones) will exhibit irregular wear on a brand new car - the tread pattern can be designed to be "good" or "bad" for this type of wear. Irregular wear can also be an unstable process, meaning once it starts, it's a runaway train that can't be stopped - even if whatever started it is fixed.

That tire looks like a Michelin? They're usually quite good for designing tread patterns...

The couple of times I've had scalloping like that it's been on the rear of fwd cars and new shocks cured it. Not sure if that translates here. 

Cupping is caused by loose parts and/or bad shocks/struts. Loose tie rod ends will definately contribute to this pattern.

Once it starts on a tire, that tire will not come out of it, it will continue to cup even after the loose/bad parts are replaced.

3* of camber is a lot for a DD. 1/4* to 1/2* for best tire life.

(8 years as an alignment tech)

collinskl1 said:

Can you take a picture of the whole tread surface? It looks like "heel/toe irregular wear" on the inside shoulder, but there might be more that can be seen from the whole tread width.

That tire looks like a Michelin? They're usually quite good for designing tread patterns...

Sadly I put the car away for winter already and I won't see it again for 6 months. The wear appeared to affect the inside 2.5" or so of the tire. The tire is a Sailun Atrezzo SVA1.

SaltyDog said:

Cupping is caused by loose parts and/or bad shocks/struts. Loose tie rod ends will definately contribute to this pattern.

Once it starts on a tire, that tire will not come out of it, it will continue to cup even after the loose/bad parts are replaced.

3* of camber is a lot for a DD. 1/4* to 1/2* for best tire life.

That all tracks with the parts I'm replacing. Struts last year and tie rods this year. I'll look at everything else on the front end before I put it back on the road in the spring. Might just need a full front end overhaul, she does turn 21 in 5 days.

It's way too much camber. I want to drop it closer to 1/2° when I get realigned. I do like the extra caster though.

Lack of rotation will do that, as will cheap tires with poorly designed tread blocks.  Basically, SaltyDog covered it.

3 degrees is nuts.