Causes wear to front tire inner shoulders?

[FireFox31]

What could cause wear to the inner shoulders of the front tires on my 2000 V70 FWD NA automatic? How is front camber adjusted?

My spring suspension is likely original with 230k miles, tie rod ends are fine, front right ball joint is worn (though front left wears similarly), and the car pulls slightly to one side while driving. I plan to replace all front and rear springs, shocks, and struts, but I'm taking this as an opportunity to learn about the system for future maintenance.

In the following picture, the front tread is 4/32" on the outer channel and 4.5/32" on the inner channel. The rear tread is 6/32" on both outer and inner channels. The front outer shoulder wear might be due to the 2/32" extra wear or it might be a little excessive. The front inner shoulder wear is clearly excessive.

[BlackBart]

Too low pressure causes the outer edges to wear faster than the center. Vice-versa for the opposite, too much pressure. One tire edge wearing would be alignment setting - too much negative camber, too much toe, that sort of thing. If it's even, I think that's tire pressure.

<EDIT> I mis-read, sorry.

INNER edge of front tire is likely toe-out, or too much negative camber.

[foggydogg]

Caster and camber are difficult/near-impossible to adjust in normal service. That wear looks like a toe problem to me.

[scot850]

It can be as the guys have already said, a toe out issue, but your worn ball joint, control arm bushes potentially and inner/outer tie rods could all contribute to the issue.

I would replace the control arm with the worn ball joint first, and while at it check for play in the other control arm, and the tie rods. While you are at it, check the read axle mounts are not rusted or cracked as they are part of the alignment process. I found this out after reconditioning a V70 which my buddy now has. I took it to the dealer for the alignment and they found one of the rear adjustment blocks seized and starting to crack.

Then when mechanically good have the alignment re-checked and set.

Neil.

[FireFox31]

Caster and camber are difficult/near-impossible to adjust in normal service.

Haynes says that camber is adjusted by loosening the steering knuckle to strut bolts, shifting the steering knuckle angle, then tightening the bolts. Am I reading that right? I wonder if an alignment shop would actually do that after I replace my suspension. That's why I want to understand this, so I can tell a shop to do it and check if they did.

I run my tires at 32 psi front, 31 psi rear year round in New England four-season temperatures. Wear seems even across the tire so I trust that inflation is correct.

While you are at it, check the read axle mounts are not rusted or cracked as they are part of the alignment process.

Where are the rear axle mounts? Which part is it on the diagrams of the rear suspension arms and rear spring suspension. Looks like the axle bolts on the large metal tube of the suspension arm.

Haynes says that on the rear, only the toe can be adjusted. It's done by "altering the position of the rear suspension transverse arm-to-trailing arm mountings." Are they (and scot850) talking about the trailing arm bushings? My rear tire wear seems ok so these questions are purely academic. Thanks.

[scot850]

No's 5 and 6 as I recall. #5 was the issue on my car. The parts was aluminum and the bolts seized into it.

Tire pressures sound about right. I run mine higher but then we are at around 3500ft here. Similarly I get even wear.

As to camber adjustment there is none. You may gat a very small amount within the 2 bolt holes at the base of the strut but that is it.

The rear may be fine, but if it is worn it can affect the way the car handles. I think it is not an issue in this case, but don't take for granted.

Neil.

[abscate]

The fronts wear faster than the rears so the front back difference is normal.

That looks pretty typical to me, maybe a bit more air in the tires would help , maybe 35 psi?

You don’t adjust camber routinely on these cars, just toe. If camber is way out it’s worn out ball joints or a bent knuckle.

99-00 only on that steering knuckle

[foggydogg]

Caster and camber are difficult/near-impossible to adjust in normal service.

Haynes says that camber is adjusted by loosening the steering knuckle to strut bolts, shifting the steering knuckle angle, then tightening the bolts. Am I reading that right? I wonder if an alignment shop would actually do that after I replace my suspension. That's why I want to understand this, so I can tell a shop to do it and check if they did.

I run my tires at 32 psi front, 31 psi rear year round in New England four-season temperatures. Wear seems even across the tire so I trust that inflation is correct.


Haynes says that on the rear, only the toe can be adjusted. It's done by "altering the position of the rear suspension transverse arm-to-trailing arm mountings." Are they (and scot850) talking about the trailing arm bushings? My rear tire wear seems ok so these questions are purely academic. Thanks.

The only way to adjust camber - without installing the Racer Boy adjusting rig to the top of the strut body mount - is with some offset bolts in the strut/knuckle mounting holes, and then you don't get much. If camber is way out of spec, something is worn out or bent (ask how I know about the bent part, pics of a mangled subframe are elsewhere on the forum.)
Wear on both edges of the tires would indicate low pressure, but on just the inside or outside is a toe-in/out issue.
Some high performance tires have a max pressure much higher than typical touring tires; one of my cars came with tires rated at 55psi, and I run them a bit heavier. Most of the fleet I set a t 35 to keep from getting (more) confused.

[WhatAmIDoing]

I had suspicious inner and outer edge tire wear (much more inner) after overhauling my front suspension on the 98 S70. It was likely due to cornering a bit too aggressively. So you might need to calm down the spirited driving. If both sides are wearing the same, then it may just be driving style. P80s are known for eating front tires. You didn't say how many miles of wear was on those tires?

I run 36 PSI in all 4 tires, checked when cold.

If I recall correctly from my last alignment, tech said camber isn't really adjustable on these vehicles.

[FireFox31]

Thanks for the great info. I have to check my notes but I think I've been driving with a slight misalignment, pulling to one side, for quite a while. Wanted to replace the whole suspension before bothering to align. Now I know.

I don't know if I'll replace those rear trailing arm bushings, delta links, etc. When I bought the car, the final mechanic's notes from the previous owner said "a rear shackle is bad". Maybe I'll spend the time to try and confirm what has failed, but the front/rear spring suspension is certainly original and is surely bad, thus being replaced first.