tire lifespan in AWD legacy

[friendly_jacek]

My 2000 legacy wagon (AT) eats through tires like crazy. 50000 miles and had to put 3rd set of tires. The stock RE92 lasted only 25000miles with uneven wear (outer edges IIRC) despite 5000 mile rotating and aligment check at 20000 miles. Well, I thought OEM tires were not good and but bought a lifetime alignment with new tires just in case.

 

Today I just learned that the RE910 replacement tires were shot after 25000 miles (inner edges wear). Tires were rotated and alignment required adjustment at 40000 miles. The tire mechanic said "typical for AWD" but prorated the warranty (I had 45000 miles or so warranty on RE910s) so at least I got some discount on the new RE950s. The car is driven mostly conservatively in city (wife's commuter car) with some hwy trips (family car) and rare towing. I like to keep a decent tire pressure (40 PSI) for crisp handling, better MPG, and heavy load while towing.

 

Questions:

1. Is AWD hard on tires?

2. Am I hurting the the tires by 40 PSI (tires are rated at 44 PSI)?

3. Or alternatively, do tire shops mess up alignments for purpose so the customers would come back for tires soon (my conspiracy theory)?

[jcniest5]

Tires should last longer than what you've experienced. My 91 Leggie went through roughly 45K on a generic tires (cheapy ones from Kelly's) and I only rotated the tires three times (if not less) during the whole time. They would have lasted even longer if I had my car aligned and rotate every 6K miles. Been driving (and still) unaligned. I did my alignment awhile back using plain eyesight and have been that way since, which wasn't too bad. But I should have it aligned correctly anytime now as I just bought a new set of tires.

 

I say your PSI is somewhat high, making the tires wear faster. Don't use too little or too much air, just enough, it's the most efficient way prolong tire life, tire/thread wear and fuel economy.

[SevenSisters]

A tire with a 45K warranty is not regarded as a good wearing tire. Look at all the 60K and 80K warranties out there. A 45K tire may however, may give better traction than a higher tread wear rated tire. It’s a trade off in many cases. However, a 45K warranty may also just mean a cheap tire and tread compound.

 

 

Subarus are not known to be real tire eaters. Wear should be no worse than a FWD vehicle. That said, city driving is the worst for tire wear. Want high tire wear? Those tires may yield 100K if you just drove back and forth between LA and NY on the interstate.

 

 

If you’re getting wear on inner or outer shoulders, but not both, it’s primarily an alignment issue.

 

 

Tire warranties get you back to the dealer to buy another (third) set of the same crap Bridgestone tires. How did they prorate you? On the list price or a typical actual selling price? Did you pay a second time for valve stems, mounting and balancing? Pay for another alignment? Check TireRack or some other online dealer to see what the tire should actually sell for. If you paid anything other than a reasonable prorated tire price, you paid again for service and rubber you already bought last time.

 

 

In my opinion, 44 psi is way too high. Stick with, or only slightly exceed, Subaru’s recommendations. Everyone disagrees with me, but overinflation leads to excessivve wear on both shoulders. Coupled with a toe ssue, it gets worse.

Summary:

You have low UTQG rated tires.

City driving is rough.

The dealer made another boat payment.

[Mark-O-Back]

Hey,

That's not good tire wear as you know.

My 97 OBW went 70K on the original tires. They had tread left when I got new ones. I always ran the air pressure listed on the door jam. The car felt like it was on rails, very safe feeling and I had no reason to want anything different in the handleing department.

When I got my new tires the shop put close to 10 psi more in the new ones. The rails where gone road noise up. I lowered to the prescribed pressure and I am convinced that this is better.

I suggest trying the OEM recomendation for a while. You may find you like it. IF the wear is still uneven your rig has a problem.

My 4 cents.

Mark-O

[jcniest5]

BTW, I wasn't saying I had good tires. I indicated mine were cheap tires, but they still had good thread when I replaced them due to one of them being warped, making the car really shaky. Like I said, if I had rotated them regularly and aligned my car properly, I may still be driving them today as their thread were still good.

[rweddy]

In my opinion, 44 psi is way too high. Stick with, or only slightly exceed, Subaru’s recommendations. Everyone disagrees with me, but overinflation leads to excessivve wear on both shoulders. Coupled with a toe ssue, it gets worse.

 

.

Yep I agree, you do not go with what is on the tire, you go with what is on the car. Check you door jams and run the factory tire pressure, or very close to what is there.

[friendly_jacek]

A 45K tire may however, may give better traction than a higher tread wear rated tire. It’s a trade off in many cases. However, a 45K warranty may also just mean a cheap tire and tread compound.

 

 

 

Subarus are not known to be real tire eaters. Wear should be no worse than a FWD vehicle. That said, city driving is the worst for tire wear.

Ya, potenza RE910 is considered a performance tire with 400 threadwear rating.

 

The more I think about it, city driving may contribute here a lot. I also went through brake pads in 45000 miles at the same time. With hwy driving these things would last at least twice as long (miles-wise).

 

The only thing that bothers me is that eneven wear pattern. I guess I will request alignment check every time tires are rotated.

 

Thanks for all that replied.

[mrk610]

I have 47 k miles on my 02 outback with the oem re92 tires . I still have about 1/2 the tread left . I run about 2 psi over the door numbers . I am going to get new tires due to the fact that they suck in the rain and are gettig noisy. I rotate every 7k miles and while the tires/wheels are off I clean and wax the inside and outside of the wheel .I have driven 2 trips to FLA and go to the mountains skiing every winter . I think you should try to run the psi on the door .

 

 

Mike

[Setright]

40psi does sound high, but it all depends on the tyre size. A 205/50R16 tyre would work well at that pressure, although I would probably go for 38psi.

I run my 195/60R15 Potenzas at 35 front, 31 rear. Door sticker says 31/29.

 

I think 25k miles from a set of tyres is okay, as long they have given you good grip in the process. 30k would be optimal.

There are tyres that will last 40k and above, but often this is at the expense of handling - and safety!

 

In terms of alignment, the recommend toe-in is ZERO on all four wheels.

[Setright]

Oh, and AWD does not eat tyres. What baloney!

[shortlid]

We replaced the stock soft compound Bridgestones on our '98 Legacy L wagon with only 30k on them and they weer SHOT!! We have since switched to Michilens and we have goten a min. of 80k out of them!! Just needed routine alignments and rotation ever 7k.

[axxiom]

Tire wear on my 2000 Legacy GT wagon w/5 speed and 34000miles on it is also high. I replaced the stock Bridgestone RE92s at 17000 miles with about 4-32nd inches of tread left, a touch early but I never really liked Bridgestone tires' handling.

My Yokohama Avid tires also with 17000 miles on them have nearly 5-32nd inches of tread left, and these have a higher wear rating(360) than the Bridgestones.

Tire wear is even and smooth and I've always maintained tire pressure at 32-35 lbs. They are rotated every 5000 miles. I do mostly freeway driving.

My previous car was rear wheel drive, weighed about same and always had all season performance tires(size 205/60/15) on them as does my Suby with its larger diameter tires(205/55/16) With tire wear ratings much the same as my Yokohamas and the same type of driving conditions, I got about 38000 miles on those.

Friends with AWD vehicles(Honda Element and Subaru) get about 23000 miles on their car's tires. So, I think that higher rates of tire wear just goes with the territory of AWD, sadly.

[subawoohoo]

but overinflation leads to excessivve wear on both shoulders.

 

nope, overinflation gets you wear right in the center.

 

are your tires wearing on both sides or just the outside. if outside, both fronts? all tires? if just the outside, for some reason you got positive camber.

 

as for the balding quickly problem, I suggest just shopping arround for a different brand. my moms tires on her Buick are dying pretty fast, (30,000 miles) and i think they are just cheapys. Just be sure you air them up to the pressure on your doorjamb, thats the pressure recomended for your weight. (the car)

 

 

 

Hope that helps

[DerFahrer]

The pressure on the tire is the MAXIMUM pressure the tire can hold. That's just about always waaay too much for the sake of tire wear. Your gas mileage might improve a bit, but those savings quickly vanish when you have to replace the tires 3 times as often.

 

I have Michelin Symmetries on my Legacy right now and am 100% satisfied with them. They're a quiet tire with good ride quality and better-than-a-cheap-tire grip. I've done everything from going through mud to running the Dragon with them. $400 installed but that was with lifetime rotation and balance, so I got a deal actually...

[SevenSisters]

nope, overinflation gets you wear right in the center.

 

 

As you over inflate a tire for the load it carries, you round out the tread radius. You loose contact area with the road and traction. Check it out by driving over a piece of paper on a smooth surface and seeing what parts of the tire actually contact the pavement at different pressures.

 

As far as outside wear on both shoulders goes, here’s my wear theory, although none of the tire manufacturers’ websites agree with me. I don’t think they’ve rethought things since the days of bias tires. No one on this board probably will agree either, but this information is only worth what you’re paying for it.

 

 

 

As you increase pressure, even with a radial, you round out the tread. Remember the driving over paper experiment? The center of the tire has a larger diameter, carries more of the load, and makes good contact with the road. The shoulders on the other hand, are smaller in diameter, don’t have as much weight on them, and slip and scuff as the tire revolves.

 

 

 

Picture three bicycle tires attached side by side. The center one has a diameter of 26”. The two on the outsides are both 25.5”. If they were separate, the large one would travel further in one revolution than the smaller ones. You do the math. Now, for each revolution the assembly turns, the smaller tires have to actually turn a little more to keep up with the larger one. This creates scuffing, squirming, and leads to wear of the smaller, outside tires. To me, this is analogous to shoulder wear I've observed running at higher pressures.

 

 

 

I know, all the internet pictures show, and people think that tire wear comes from touching the road, but if alignment is correct and you’re not trying to push the tire down the road sideways due to toe problems, I say over inflation causes shoulder wear due to poor contact with the road.

 

 

 

Look at the irregular wear created by bad shocks and struts. This is also caused by tire squirm and scuffing due to loss of contact with the road.

 

I'll admit there may be some steering geometry issues with Subarus that accelerate shoulder wear during turning in city driving senarios, but whether I'm right or wrong on this theory, I've been sticking ptetty close to what the tire placard says.

[Setright]

Well, I agree on the point that things have not been rethought since the bad-old-days with cross-ply tyres. Radial tyres don't actually change the shape of their contact patch very much. That's the whole idea behind the radial construction, to keep a uniform contact patch for a variety of pressures and driving conditions.

 

Very large pressure variations will of course cause uneven wear. The wear I see on the outside shoulders of my tyres is no doubt due to "excessive speed in bends" as listed in my old Legacy owner's manual. This is impossible to overcome by changing the tyres pressure.

 

People who experience wear on both shoulders have serious pressure or alignment issues.

 

 

I am sorry to make your prediction come true, but very low pressure will wear the shoulders. Consider that the point of tyre in contact with the road, vertically below the hub center is STANDING STILL relative to the road surface. Either side of this, the tyre is moving. Either side, there is still contact between tyre and road. THIS is what causes most of the wear. The tyre is rubbing as it rotates.

Less pressure means more contact, and in the extreme, the center of the tread will have very little vertical force acting through it.

 

The top of the tyre is travelling at TWICE the speed of the car itself. Only the points horizontally to each side of the hub center at moving at the same speed as the car.