Inside shoulder wear on '04 WRX

[y_p_w]

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.

 

[mulder]

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.

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.

 

[Dmitriy]

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]

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.

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.

 

[Clifford Heath]

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.

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.

 

[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.

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).

 

[Clifford Heath]

My problem is that I'm off the throttle coasting to the card
key reader.

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

 

[bugalugs]

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

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.

 

[Carl 1 Lucky Texan]

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.

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

I dunno


Carl

 

[y_p_w]

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

I dunno

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° left, -0.09° right, -0.19°
total) but is otherwise within specs. Left rear camber is -2.5°
(spec is -2.3° to 0.8°) 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.

 

[y_p_w]

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.

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.

 

[nobody >]

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.

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.

 

[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.

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.