HammerDown

My rear tires (Ecsta Supra 712) are nearing the end of their life, and I noticed that the center of the tire, around the central water groove, has worn much more than the rest of the tread, including the tire shoulders.

I run the recommended factory pressure of 30 psi all around, so I don't think they're overinflated.

Is this normal for rear tires? Do Kumhos do this more than other tires? Could it be an alignment problem?

The front tires do not wear like this at all. In fact, almost all of the wear on the front tires is around the shoulders from all the hard cornering, with lots of tread left in the middle of the tire. Perhaps with the 30 psi all around, I'm underinflated in the front and overinflated in the rear, but then again, this factory recommended pressure for my base suspension 94.

SBNova

Cant really say for the Kumho's, but I run a 295/50 on my Nova and they have always been wearing in the center more. I think its because of the width. The fronts may be more even due to the camber and cornering forces wearing at the edges. I run 24-26psi in my rears to keep them wearing more even even though the recommended is like 32psi. Im on the second set and it seems to really work. This set has 25k on them AND theyre 7 yrs old!

bogus

no funky wear here. I have 24k miles, rotate regularly and keep the inflation at 40psi.

HammerDown

I assume you mean rotate front to back, right? Do you rotate them every 3k?

What is factory recommended pressure for your car? 40 psi sounds awfully high for normal street driving. That's more like a track or autocross pressure. I can't imagine you'd have any rear wheel traction at that pressure. And I still can't believe you have 24k on those tires at that pressure without seeing most of the wear in the center of the tire :eek:

vader86

No problems for me, i run 35psi all around.

If both rears are like that, i guess there could be something up with the alignment, or maybe defective tires, since it doesnt seem as if yours are overinflated.

hmmmm :confused:

NOT-MEE

I run 33 fron and 35 rear i rotate them every oil change.and after i have gone to the track.

HammerDown

I don't think the alignment is an issue because it's wearing right smack in the middle of the tire.

Could be a defective set of tires, but I think I remember the Goodyear GSCs looking exactly the same when I replaced them with the Kumhos.

Maybe I'll just have to try not to push the gas pedal down so far :reddevil

CoolVette86

Mine's 35 all around as well. The wear is fairly even, although a wee bit more at the corners.

Nathan Plemons

Mine seem to be wearing evenly, of course they are only 275's. I keep them inflated at 35 PSI. Under inflation should make the outsides wear more than the inside and vice versa. Strange.

bogus

1) I rotate every 6k or 7k miles...

2) recommended is just that - recommended. I have tested other rates, and the tires just don't wear as well. 40 seems like a good pressure. It worked great with my BFG Comp TA's, to the tune of 45k miles!!!

HammerDown

Mine are 275s on the rear, too. Although I'm cursed with the 8.5 inch rim on the fronts, so I'm running 255s up there. Can't rotate at all.

I guess I've gotten pretty good mileage on these rear tires. It's pretty close to 20k, and for the most part the wear is even. Maybe what I'm seeing is just the shape of the Kumho tire. When they were new, they sort of sloped down from the outside edges toward the center rain groove. That's basically what I'm seeing now, where I'm down to the wear indicators in the center groove and at about the same depth on the outer inch and a half of the tire.

Maybe it's just an optical illusion.

Incidentally, I tried running 35 psi all around for a week last month, and while it was great for handling, it made the car feel like it was going to fall apart over every little crack in the road. So 30 psi (which is the factory pressure for my car) ended up being a good compromise for everyday driving. I'll pump them back up to 35 or even 40 if I ever do another autocross, though.

5 psi makes a world of difference in the way the car turns in.


[Modified by HammerDown, 9:57 PM 9/24/2003]

Bob Mosaic

the tire is slightly too wide for the wheel. run a narrower tire so it looks too small but it really isn't. I have 10.5in fronts running a 275. the tires appears tooo small but itlays flat to the road with no buldge in the middle.
good luck,
robert

HammerDown

Interesting, the stock size is 285, so this tire is actually smaller. And it definitely looks smaller than the Goodyear 285/40/17 that was on there before.

Good advice on tire size vs rim size, though. Some people are running way too big of a tire on their rims. Sure it will fit on there, doesn't mean it will perform the way it was designed to.

Alex D

Factory recommended pressure for my 96 LT1 is 29/29 psi

1989redvette

i have the 712's as well mine are wearing o.k. i run 30 in the fronts and 28 in the rears...40 is way to much!! as for the wear in the center of the tire i would look into the fact that alot of the water channeling tire casings are rounded thus the tread in the center is not as deep on the sides..that way it can funnel more water out to the edges and reduce the hyroplaning effect... :cheers: