Excessive rear tire wear

[Buzzinhalfdozen]

So I put a new set of Cooper Discover at3 tires on about 3,000 miles ago. I looked at them today and the fronts are still new at 16/32nds but the rears are already worn to 13/32nds maybe a little less. 

-I'm not out doing burnouts or even launching starts. 

-Little to no hauling or towing with these tires. 

-Pretty much all highway miles with maybe 20 miles of dirt road.

-60psi

It should be noted that my last set of tires (Firestone Transforce AT) wore quickly also, about 20k and they were down to 4/32nds. I just chalked it up as junk tires.

So what gives, I know they're softer tires but at this rate I'll be lucky to make it through the winter.

One theory I have is maybe my rear limited slip isn't releasing and dragging the inside tire through corners? The only reason I say this is a while back something in the back made a binding/clanking noise through tight corners while I was towing. It sure sounded like an LS issue. Couldn't replicate the noise the next day and every thing looked good when I pulled the cover. 

Any thoughts are appreciated cause tires ain't cheap!

 

[Mopar1973Man]

Most likely over-inflated. Even my truck using the calculated formula I get roughly 57 PSI on the front axle and about 40 PSI on the rear axle. Again you can't use these numbers because of weight differences and tire differences as well.

http://articles.mopar1973man.com/general-cummins/35-exterior/354-tire-inflation-formula

 

[IBMobile]

I have to agree with Mike, over inflated. I run that kind of pressure 65-70 psi only when I have my 5er hooked up, about a 1000lb in the bed. When unloaded I air down to 45 psi.  

[CTcummins24V]

Measuring in the middle of the tire? I have about 25,000 miles on my at3s and I'm guessing I won't get 15,000 more out of them, maybe not even 10,000 The middles are worn more than the edges and I run anywhere from 55-65 psi. 

[Buzzinhalfdozen]

Good point and this did cross my mind.  I started out around 45psi but I didn't like the way it drove on the highway. Back end felt a littlesoft on high speed corners. Should mention they are 285/75/16 so I figured more sidewall=more psi to help the sidewall from flexing. Seems to drive the best around 60psi. 

Last set of tires were stock size and run at 40ish psi.  

[Mopar1973Man]

Might want to try the math out and see if it helps or not.

[dripley]

I have Cooper ATP's from discount tire, there version of the AT3. I got 65k out of them. Ran them around 50 psi most of the time except when towing. I tow heavy but not often. 75% of that are highway miles and the rest around town. That was as good as any Michelin I ever ran. On my second set now with about 28k on these and they are about 1/2 gone. I will be interested in seeing how long they last since I have a new clutch and a new Comp to play with. I ran the first set with no chip, only the rv's their entire life.

[AH64ID]

Larger tires generally need less air per pound of weight than smaller ones, and 60 psi is a lot of air for a 285 and no load. 

 

The initial soft feel was probably the rubber being new and not the lower pressure. 

 

When empty I would be surpirsed if you require more than 40-45 in the rear tires. 

[Mopar1973Man]

I've heard of some long highway miles on Mitchelin's. The most I can get from a set of tires is about 30-40k miles. Too much offroad driving that tends to shorten the tire life. I'm running a China made Black Lion HT's to see if I can break out of that problem. I like the traction of the A/T's just doing like the short life span. H/T's seem to be holding up even better but require more 4WD use on dirt roads and ice.

[IBMobile]

Not all tire sidewalls are the same. I've bust a lot of ties off of rims over the years and the Michelin ® tire always had the stiffest side wall to work with.  My work van always had Michelin ® tires on it because of the load I carry and could drive at 70 mph with out it getting all squarely.  I needed new tires and Michelin stopped making that module so I got a set of Hankook® tires and put them on the back.  Now if I go over 65 mph it feels like a death ride with catastrophe around the corner.  I've found a good stiff side wall construction is just as important as air pressure in tire performance and vehicle stability.

[dripley]

65k is the most I ever got on the Michelin's. I ran 2 sets of them with the same results. I too have seen a lot folks stating high miles on them. A lot higher than I was seeing. Those same tires are about $250 a piece right now and I just dont like paying for them. The ATP's are running about $200 a piece. i tired of having to take out a small business loan just to buy tires.

[Buzzinhalfdozen]

Ok I'll play with the air pressure a bit hopefully this helps. 

My wife has driven it a few times recently....maybe I should be questioning her about the worn tires. 

[Mopar1973Man]

Just now, Buzzinhalfdozen said:

Ok I'll play with the air pressure a bit hopefully this helps. 

My wife has driven it a few times recently....maybe I should be questioning her about the worn tires. 

Oh your playing with fire now... Nothing like a woman scorned...

[Cowboy]

I through a set of these on this summer when they were discounted.

http://www.discounttiredirect.com/direct/findTireDetail.do?ra=filterTireProducts.do&fl=&pc=27009&counter=0&ar=75&rd=16&cs=265

Edited December 11, 2015 by Cowboy

[Buzzinhalfdozen]

1 hour ago, CTcummins24V said:

Measuring in the middle of the tire? I have about 25,000 miles on my at3s and I'm guessing I won't get 15,000 more out of them, maybe not even 10,000 The middles are worn more than the edges and I run anywhere from 55-65 psi. 

Yes measured from the middle of the tread. I'd be happy with 30-40k miles but right now I'm averaging 1/32nd of wear per 1000 miles so...

[IBMobile]

I blame everything on my Wife. It's her fault I married Her. 

Edited December 11, 2015 by IBMobile

[dripley]

36 minutes ago, Cowboy said:

I through a set of these on this summer when they were discounted.

http://www.discounttiredirect.com/direct/findTireDetail.do?ra=filterTireProducts.do&fl=&pc=27009&counter=0&ar=75&rd=16&cs=265

That is the what I am running right now.

[The_Hammer]

I ran the numbers and I should be running 39 psi front and 25 psi rear. My tires are 315/75R16 Goodyear Duratracs. Load range E, 3860 lbs @ 65 psi. I'm currently running 45 psi front, 40 psi rear. 

I used the weights from Mike's article and added 100 lbs total for the rear and 200 lbs total for the front due to bumpers. It's not exact but should be pretty darn close. 

Edited December 11, 2015 by The_Hammer

[Mopar1973Man]

@The_Hammer What was your axle weights? Front and rear.

[The_Hammer]

1 hour ago, Mopar1973Man said:

@The_Hammer What was your axle weights? Front and rear.

I don't know what they actually are yet, I still have to get to a scale. I was using the weights from your article to get a round about figure since our trucks are fairly similar.