ym42

Both rear tires are almost bald ( very little thread depth ) in the center but have plenty of thread on the sides, tire pressure normal. Didnt rotate, all highway driving, about 27k miles on them... Normal ??

07BLACKGT

Usually everyone says that's a sign of over-inflation, but mine are never higher than the recommended PSI and the center of mine always wears out first on the rears.

So yeah, I guess it's normal. I'm sure some of the other guys in this section will know more about this though. I wish I could get 27k miles out of a set of tires. :[

MythEyeLess

Try rotation or/and alignment. Balance i think would be good too(couldn't hurt). Mine does something similar and i talked to a SAE Master tech and he told me to get 'em aligned. GL

Stoenr

Typical of a rear drive car. More pronounced with wider tires as well. Fronts will wear more on the edges, and rears down the center.

candymanjl

personally once you're not running the stock size and brand tire their suggested tire pressure is kinda worthless except as a starting point.

with a wider tire than stock you're distributing the same amount of weight across a larger contact patch. so where the small tire may need 32psi, the wider tire with the larger contact patch my only need 26psi. my buddy's 04 GT had a 305 rear tire and it wore perfectly even across the whole tire with only 18psi cold pressure. that probably turned into 22-24 psi by the time the tire warmed up and got to highway speeds.

ultimately tire wear should be your indication of what pressure you need to use. I don't care what the sticker in the door says if your tire is bald in the center and full tread on the inside and outside, you're running too much pressure. full tread on the center and bald on the outside and inside then you're running too little pressure. especially in the rear end where there's no adjustable camber or toe to worry about tire pressure is the #1 factor in even tire wear.

in the front tire pressure is just as important but since the tires are steering and changing angles from toe/camber it's a little more complicated. I would still suspect tire pressure first, then worry about an alignment later once you know that the pressures aren't effecting the wear.

Norm Peterson

From your description:

Tire pressure equalling "normal" may still be too high for the driving that you do - which is really very gentle, especially if you're very lightly loaded most of the time. What's not happening (that recommended tire pressures and alignment specs are partly based on) is things that tend to increase rear tire shoulder wear, such as harder and more frequent cornering or carrying rear seat passengers or much trunk load.

Alignment is unlikely to help the specific condition of high rear tire center tread wear.

Rotating the tires front to rear is far more likely to be of benefit, particularly if you take out a psi or two from the now-rear tires. Unless there's suddenly a big change in the car loading conditions and/or the way you drive, you need to make the rear tire tread centers work a little less hard and the rear tire shoulders a little more so.

I wouldn't bother rotating in an "X" pattern unless the tires on one side of the car were both worn more than their counterparts on the other side.


Norm

nemosgt

Alignment won't help.

Drop rear tire pressures by 2 psi or so. Smoother ride, better wear and better handling. What's not to like?

Cheers.

Stoenr

I will just quote myself.


OP is riding on OE 18"s This is normal with recommended tire psi.
19 years in the tire business..........
Sure too much psi will cause it to happen quicker, but to someone who keeps it where it's recommended, and drives a tad on the aggressive side or even normal for that matter, center rib tread wear will occur on the drive wheels, its not an opinion, it's a fact.
If the only trick to even tread wear was optimum tire psi, no one would ever rotate tires........

ym42

Thanks everyone! ;-)

Norm Peterson

Mind if I ask a couple of related questions?

I'm assuming that recommended pressures are set with the full vehicle loading in mind, unless a separate set is given for some light load condition. Does that suggest that the recommended rear tire inflation pressure in particular actually represents slight overinflation with respect to light load conditions? But provided by the mfr anyway due to full knowledge of the poor average level of owner attention to tire inflation pressures, and due to it being better to be a little high for the light loads than too low for the full loads?

Am I correctly interpreting what you mean by "drives a tad on the aggressive side" to be more indicatative of hard acceleration and braking rather than hard cornering?


You certainly see a wider variety of vehicles and their overall undercar condition (and their drivers) up close than I ever will. I'm looking to see how well a couple of things that I suspect line up with what you actually see happening.


Norm