First question.

I have about 15k miles on my Falken Ziex 512's and the rears seem to have severe inside shoulder wear on them. I am going to rotate them and do the "White Mark" test to see what my contact patch looks like. The tires don't rub anything and my car is all stock so I have no idea why the inner shoulder is wearing so badly. I usually run them at 32 psi, but I guess I may need to go higher. I do have some camber in the rear from slight spring sag, but nothing crazy. Tire pressure recommendations and suggestions on the wear issue?

Next question...

Since yesterday, any time I start my car when the engine temp is just right at the bottom of the gauge (luke warm) I'll get a backfire right as my car starts up. Thats basically it. No drivability issues at all. What should I look at in terms of what may be causing that?

 

Alignment.

 

What should be changed in the rear alignment?

 

Too much negative camber if severly worn on the inside. Have it checked/ adjusted and should clear your problem. One thing I ran in to was I had to buy camber adjusters as the stock setup wouldn't allow for much play

 

I didn't know you could adjust camber in the rear, learn something new everyday I guess.

 

You can't unless you get aftermarket adjustable links.

 

So, what would cause this. The wear pattern is on the inside of the tire.

I am down to the following:
1. Pretty much everything...

Struts, springs, bearings, alignment, bushings.

It is only on this one tire. I will inspect the car tomorrow and see if it is only the passenger rear that is sitting crooked. I know it is, kind of how I noticed this. I did not check the driver side. Will check for sure in the AM.

 

Wow, that looks to me like bad negative camber and possibly an unbalanced wheel.

 

Is the car lowered?

 

Car is all stock.
Today I checked bushings, struts, camber/caster/alignment and all is good. Wheel bearings felt tight (With the wheel on and torqued I could not move the wheel at all top to bottom, front to back, side to side. Nothing moved.

Both the right and left rear wheel are well within spec (from alignment shop). The only thing that any of us can think of is that either the spring is weak or it was simply a bad tire. Tires are Federal something-or-other 595 in 235/40r17. I am stumped. Did I miss something while troubleshooting? I went through my FSM (not haynes, real FSM) and tried all the troubleshooting I could find, all with the same result that the components are in good shape. Never wrecked, subframe is rock solid, underneath is not pristine, but not abused at all.

I have a new tire on order. Will continue to scratch head and ponder. Maybe a beer is in order?

 

Working in the tire business I have found that some cheap tires like tigerpaw, falken and other off brand names get choppy like that very fast. Stay with name brand tires like bridgestone or michelin. You get what you pay for with tires.

Just last week I had a customer come in saying the tire shop who put his super cheap tires on say that his alignment is off causing his new tires with 6,000 miles on them to get all choppy.

I aligned it making almost no adjustments. Toe in the front was still in the green but i am picky so i get it close to perfect. everything else dead on.

Point is was that the alignment was good beforehand. the tires are just crap.

end rant.