oldtrlrnr

I'm running a set of Conti ExtremeContact DW's on my '06 AP2, stock 215/45-17 front, CR-size 255/40-17 rear, on stock wheels, stock alignment; been running 40psi all around since I put them on. Just noticed that after only ~ 17K miles the rears are worn thin in the middle but still have a lot of tread on the outer ribs and more on the inner ribs than in the middle. Obviously I've been running too high pressure in the rears - my bad. I hadn't been checking wear, since my oem RE050's had worn pretty evenly with same tire pressures. The fronts still have a lot of tread left, so I guess I'll have to buy another pair of the Conti DW's for the rears.

I don't recall a great disparity in wear front vs rear on my oem RE050's, though I did see more wear on the inner ribs of the rears than the outer. I got ~ 28K miles out of the RE050's. I don't think my driving style has changed much, other than slowing down some in general due to age. I still downshift going into corners and accelerate out of them, but seldom drift at all any more.

So I'm dismayed at getting less than 20K miles out of the rears on these Conti DW's. With their 300 ATQ rating I was expecting longer life than my RE050's. I have been pleased with these tires overall, better grip than the oem RE050's, pretty good in the wet, and less tendency toward snap oversteer accelerating out of low speed corners, though I suspect part of that is due to the one size larger rears.

So I'm wondering (1) what others have experienced with these Conti DW's; and (2) in general do you see roughly even wear front vs rear, or is two sets of rears per set of fronts the norm? Also, (3), I might consider reducing negative camber on the rear a little, in hopes of more tire life, but am concerned that it might impair handling.

Appreciate any feedback.

Bob

ZDan

Check rear toe. Have them set it to the absolute minimum end of the specified range. Toe is the tire destroyer...

jst2878

Need alignment

ZDan

Oh, and and you might try 32-34psi cold instead of 40.

pmptx

This. Your contact patch at 40 psi (cold we assume) is going to wear the center just as low pressures will wear the sides.

I run 35 F 33 R cold for street.

GT Motoring

Bob,

17k miles isnt out of the range for what many members have seen from a set of rears - myself included. 300 utqg vs. 140 doesn't mean mean much these days when comparing between manufacturers.

Typically we see a 1:2 wear rate for most of our street s2000 customers (two sets of rears for one set of fronts). The wear condition you described is evident of higher tire pressure than optimal (though you already knew this). Its hard to say what mileage you would have gotten out of them had they been at the correct pressure throughout their life cycle.

I highly doubt that with 17k miles on them, that your toe is out of spec unless something happened recently. If the inner and outer shoulders are fine, it is neither a camber problem, nor a toe problem and your alignment is probably fine. I don't get why people are suggesting an alignment when the tire wear characteristics you have mentioned are not indicative of an alignment issue.

With a stock alignment, the outer edges will wear quicker on the DWs than the inside edges as they have softer sidewalls. If the tread depth has a 2/32nds variance or less from lowest part to highest part, you may be able to have some sort of warranty work done through Continental. If it's more than that, Continental won't do anything for you.

As other suggested, I'd keep an eye on my air pressure a little bit more in the future. Generally a good idea to check it every few weeks or so.

If we can help with anything, let me know.

Thanks,

Austin

//steve\\

As others have said I'd back off the pressure you run. I think it's too high.

ZDan

Because certain combinations of toe and camber can conspire to give greatly accelerated wear, right down the middle of the tire.

I've experienced this myself. Max spec AP1 rear toe-in of ~0.65 degrees total, combined with maximum attainable rear camber, a few thousand miles on the road + 2 track events => middle 1/3 of both rear tires corded, with fronts less than 1/3-way to the treadwear indicators.

I've since gone to less than minimum spec rear toe, ~0.2 degrees total, and rear tire life more than doubled, approximately *tripled*.


I currently have 18+k on my RS-3 rears, with 2-3/32 to go to the treadwear indicators. Two track days on them at Mosport.

DW's should last a lot longer than RS-3s...

deepbluejh

It's also worth noting that the RE050s have a lot more reinforcement than the DWs, which means they will probably be more tolerant to higher tire pressures without warping.

GT Motoring

That's quite an interesting phenomenon and one that I've never heard of, even when I worked for a large national tire manufacturer. I'm not saying it didn't happen, but when the OP obviously states that his tire pressure was too high, I'd point to that as being the main culprit.

There is a lot more that goes into tire wear than just miles. Type of asphalt used and how porous and grainy it is being the first. Driving style being the 2nd. Im tired of people having blanket comparisons with completely different variables. The information on this site is so skewed. Im NOT saying you're wrong and have no right to say so. I'm just saying that nobody should jump to conclusions about things like this. You've had RS3s last 18k miles, I've had them last 6k worn even all the way across. That doesn't mean a thing to me.

OP, you can get your alignment checked if you want, and it might be a good idea, but in my experience (for what its worth), your issue is created by a tire pressure issue.