Inside shoulder wear on '04 WRX

Well - I only got about 19K miles on a set of Pirelli PZero Nero M+S in stock size (205/55R16). The inside shoulders of all tires are wearing faster than the center of the tread - especially on the left side. That might have more to do with my taking a sharp right turn into a parking lot at work. I'm thinking that these tires might not be well suited to the negative camber in the factory alignment settings for the WRX. The centers of the treads looks like they could go another 20-30K miles if properly rotated. I've also got one repaired tire, and another one with a screw currently lodged in the shoulder. Given the nature of Subarus to prefer same sized tires, I think it's time for a full replacement.

The alignment seems to have a slight non-adjustable issue, so I don't think that's causing the premature wear.

The Pirellis never really impressed me as a true all-season tire. The tread pattern was the same as their 3-season version, and the only siping was (barely) on the shoulders. I'm thinking maybe the new Bridgestone Potenza RE960AS. They look more like A/S tires, and I'm going to be taking my WRX up to the Sierras when there's light snow and I don't want to put on chains if I can help it. I also hope the inside shoulders stand up better to wear.

Reply to
y_p_w
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Hard right turns will transfer the load to the outer shoulder of the left side tires, so that does not account for wear on the inside. Camber on the front is adjustable with the eccentric bolts on the struts, the rears are fixed although there are other adjustements in the rear suspension. After you get a new set of tires you should have a complete 4-wheel alignment done by a competent alignment shop. On my WRX I have a set of PZeros in 225/50/16, they now have over 20K on them and are wearing very evenly.

Reply to
mulder

I vote that alignment is to blame. Is your car lowered by any chance? Do you have after market shocks?

Get some new tires and then make sure to get an alignment... or I bet you will have the same problem.

y_p_w wrote:

Reply to
Dmitriy

I've got a 4-wheel lifetime alignment done at a shop using a Hunter system on a scissor-lift. I even saw them do it once with those reflectors and flashing lights. I don't have the last alignment check results with me.

My setup is completely stock save the aftermarket tires. Anything was an improvement over the craptastic Potenza RE92 tires that were OEM. The deal with that turn is it's low speed almost to right steering lock. It's a narrow strip of road with the entrance perpendicular. It's a real job to get in close enough to use the card key. Everyone swings wide left followed by a hard right at very low speeds that I think are grinding the inside edge of my left tire. My building has another garage, and I'm thinking I might just avoid this one lot even if it is more convenient.

Reply to
y_p_w

It does if you're on the throttle, spinning the inside wheel on its inner edge. I've just cured myself of the particular form of glee in our Liberty RX, after the front tyres wore the inner shoulder too quickly.

Reply to
Clifford Heath

My problem is that I'm off the throttle coasting to the card key reader. It's a real pain getting close enough to the reader. Some just take a wider turn and open the door, undo the seat belt, and reach out. I really do suspect that it's the sharp right turn that's turned the right tires (and especially the right front) to almost slicks on the inside shoulder).

Reply to
y_p_w

I don't believe that's the cause. Tyres are tougher than that.

Reply to
Clifford Heath

Wear as you have described would tend to indicate a problem in the steering geometry. Although you say you have had it done I would have it done again paying particular attention to the camber/toein and ensuring that it was being set to the correct factory specs for your model.

Reply to
bugalugs

I have seen RWD vehicles with 'shoulder wear' when the toe adjustment is out.

I dunno

Carl

Reply to
Carl 1 Lucky Texan

Well - I showed the alignment results (from a Firestone shop doing a "lifetime" check) to the owner of an independent shop that's ordering my new tires. He noted that the toe isn't centered in the specified range (results are -0.09=B0 left, -0.09=B0 right, -0.19=B0 total) but is otherwise within specs. Left rear camber is -2.5=B0 (spec is -2.3=B0 to 0.8=B0) but I don't think it's otherwise adjustable. The shop owner said that the alignment results didn't really seem to account for the level of inside shoulder wear.

I'm a bit ticked off at the Firestone shop. The Sunday service advisor gave me a quote on the RE960AS and told me I could get a "buy 3 get 1 free" (theoretically expiring that day) deal if I took it in on Monday. I was willing to pay then, but he said it would be OK, and to speak to the next day's service advisor. I did that, and he said no, as did his manager. I probably could have gotten them installed by now at the same price I'm paying at an independent, but that just ticked me off.

I'm not that ticked off that I'm buying new tires. The car is paid for, and I'm looking for a tire that works better than the Pirelli P Zero Nero M+S in light snow. I really wouldn't recommend those as true all-season tires.

Reply to
y_p_w

Even though I have a "lifetime" alignment, I'm thinking of paying someone else to do it just to get the toe-in centered. I already paid that $160 and have gotten about four alignments out of it, but they seem to be willing to let the total toe stay where it is as long as it's borderline within specs. I might bring it back later, but $60 to protect a new set of $600 tire seems like a reasonable deal.

As far as the tires go, the wear pattern is a bit odd. The P Zero Nero M+S tread is assymetric. There are three tread blocks in the center with four wide channels of different widths. The center block on the inside is only slightly more worn than the center tread block near the outside. The outside shoulder does seem to show more wear than the center tread. The inside shoulder is near bald. Just a hair of the the tread design still remains. At rest, half of the inside shoulder block is off the ground. My description doesn't do enough justice, and I'll take pictures and post them here.

Reply to
y_p_w

As for the toein, ASK for it. I've dealt with alignment folks. The better ones will know what you are talking about and do it. I used to ask to have the caster moved out to the limits on a car that was constantly driven at pre '55' Monanabahn speeds for stability, the alignment tech knew exactly why and did it.

Reply to
nobody >

My problem is that this is "lifetime alignment" deal ($160 at the time). I don't know what I can do if they tell me that they won't do it again since toe-in is within specs. They just did the alignment check last weekend.

I know the independent shop is willing to center the toe-in ($55 for a front-end alignment) to center the toe-in rather than just tell me it's OK.

BTW - I got the new tires installed Friday, so no pictures of the old Pirellis. Again - my advice if anyone is looking for real all-seasons - choose something else other than the Pirelli P Zero Nero M+S. They're fine for dry or wet, but don't look for them as a good tire in the snow. They also tramline like crazy in the grooved freeways we have here in California.

Reply to
y_p_w

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