Is this a camber problem

[911 Rod]

I've noticed extra wear on the outside of one of my front tires.
Would this have to be from too much positive camber?
Can this be adjusted?
I had M control arms installed a while ago.
The mechanic set the toe to 0. I found it far too twitchy and adjusted it a little toe-in. Would this effect the camber? I didn't think it would.
Thanks
Rod

[Dave at Pelican Parts]

Unless the way toe is set on the E36 is very different than most modern cars, adjusting the toe angle (changing the length of the tie rod) should not affect the camber.

Outside edge wear can be due to too much positive camber. It can also be due to aggressive driving. I believe there are other possible causes, but they are not coming to mind right now. (I know that toe-out together with negative camber will wear the inside edges; perhaps toe-in together with positive camber wears the outside ones?)

Try checking the camber left-to-right with an angle-finder (cheap hardware store version) or digital level (expensive hardware store version), or a bubble level and tape measure. If things are not even left to right, you definitely have a problem.

--DD

[911 Rod]

Thanks Dave,
Aggressive driving? Not me. I guess I should stop trying to make my 318 throttle steer.
My plan this weekend was to compare the camber left to right.
But I only talk to you guys from work so I'm picking your brains while being paid.
If I find the camber is different can I adjust it?
On my 911 I move the shock tower. Is it the same?
Thanks
Rod

[dboyles]

I'm fairly certain that adjusting the toe does not affect the camber, but it does work the other way around.

If your stock camber is like that on an M3, you should have around -1 degree, maybe a little more or a little less. If you're off from that, then something is probably tweaked.

Anyway, to get more negative camber you've got a couple of options. The first is to buy a "crash bolt" (an eccentric bolt) that replaces the #5 bolt in this diagram. However, there's the possibility that this bolt can slip, causing your camber to change. I'm not sure if this concern is blown out of proportion or not, I just know that it's a possibility.

Another option is to shim the #3 bolts in that diagram. Turner Motorsport sells some replacement (longer) bolts with washers included. Running either one or two washers between the strut and hub assembly will give you about an extra degree or two (respectively) of negative camber per side. The downside to this is that your tire may rub the strut because of the way it's tilted.

If you're running more than a degree of negative camber, I'd recommend setting the toe to zero or you'll probably see excessive wear on the insides of the tires.

[911 Rod]

Very informative. Thank you.
So this means there are no stock camber adjustments?
I'm thinking the tire wear is from aggressive driving. These are snow tires that I put on in November. As I had ZR rated in the summer, I've been having a blast sliding around corners in the dry with the snows. They really haven't seen much snow!
The car also pulls a little bit to the tire that is wearing on the outside. The other side is wearing a little bit on the outside as well, but not as much. I attribute this to left turns are more of a sweeper than right.

[Dave at Pelican Parts]

It pulls a bit and there's uneven tire wear? Alignment. Get the alignment checked; it's probably off. The aggressive driving is probably exaggerating any wear, too.

--DD

[911 Rod]

Alignment?
If I can't adjust camber, only toe is left.
I would think toe effects both wheel even if you only adjust one.
It would just make the steering wheel off.
Caster?
I have adjusted my toe in slightly. I found 0 toe to be too twitchy as most of my driving is on straight uneven roads.

[dboyles]

Would I be correct in assuming that the control arm bushings were replaced at the same time the control arms were done? As you said, toe is the only alignment setting that can be adjusted according to factory specs. "Pulling to one side" makes me think control arm bushings or toe, but if you've eliminated those, I'm a little bit stumped.

[911 Rod]

New control arm with new bushings. These are the "M" control arms with solid bushings. Because they are very tight they have exaggerated the problem I think.
Could be tires, but I have 2 sets and have rotated them with the car always pulling to the right a bit.
Could this be a rear setting that is affecting the front?
I'm thinking in relation on how you corner balance a 911.
I bought this car used and wondered if the frame is slightly twisted.

[Dave at Pelican Parts]

The rear alignment can very definitely affect how the front end of the car feels... If you only check the front wheels, you're only doing half of the alignment job.

--DD

[Jeron]

Did you get centered or offset front CAB's? The offset CAB will effect both toe and camber, IIRC.

How are your control arm ball joints?

Spirited driving will wear the shoulders. I dont know anything about snow tires but I can image that the compound might be soft especially when warm.

[911 Rod]

New control arms with new ball joints as well.
Said bushings, meant ball joints.
"Did you get centered or offset front CAB's?" Don't know.
My mechanic knows this is a street car. Having known that he still set the camber at 0 which I didn't think was appropriate.
Yes snows are very soft and wear quickly on dry pavement.

[Jeron]

The front camber isn't stock adjustable. Toe of 0-zero is stock I think.

Hopefully he replaced the CAB's. I mostly follow M3 and I think 95 they used offset and 96+ is centered. I assume all non-M3 would be centered. Look where the rearmost portion of the control arm slides into a round bushing and see if that bushing is centered also see if it is torn. There should be two kidney shaped holes, one on each side of the bushing.

[911 Rod]

What are CAB's?
I was told these are E30 M control arms.

[Jeron]

Control Arm Bushing.

It is located "where the rearmost portion of the control arm slides into a round bushing." The round bushing is the Front CAB.

[dboyles]

Originally posted by Jeron
I assume all non-M3 would be centered.

I believe it's the other way around (from what I've read). The E30 M3, '95 M3, and non-M E36 have the offset bushings, and the '96-'99 M3 has the centered bushings. I think.

Also, Rod, I'll tell you that the solid ball joints have a bad reputation amongst racers and track guys. Apparently they're more prone to failure than the heat-treated ball joints (made by Lemfoerder or however it's spelled). I wouldn't be too concerned with this on your street-driven car, but I probably wouldn't throw R-comps on and turn it into a track car. I don't know anybody who's experienced that failure first hand so perhaps it's blown out of proportion by the Internet - you know how that goes.

[911 Rod]

Sounds like I just need to find a good place for a 4 wheel alignment. I can do the toe myself and do quick check on camber but not a true set up.

[dboyles]

Just as a warning, some places will turn you away for an alignment. In a way, that's a good thing. BMW calls for certain specifications when the car is aligned (weight ballasts in the seats and a full tank of fuel, I believe). If a shop aligns your car to factory specs without weighting the car properly when they measure, the actual alignment is going to be out of spec. And of course there's the problem of them adjusting and not allowing the suspension to settle, etc. It all comes down to the fact that you need a good alignment guy - a $40,000 Hunter rack isn't any better than you in your garage if the technician doesn't know how to use it and/or doesn't care about the quality of his work.

[911 Rod]

Ya I know about the concerns about an alignment shop not doing a "spec" job.
Seems like every time I take one of my cars in I'm re-adjusting the toe myself afterwords.
But this time I'm stumped on the pulling and outside tire wear.
I can chalk the tire wear to aggressive driving, because I do corner hard.
Is there not some way I can trouble shoot the pulling?
Adjust the opposite rear suspension down to compensate?

[dboyles]

Did you ever figure out if your lower control arm bushings in the front are okay? They're one of those wear items that I'd start looking at once you've got ~50k miles on them, so if your guy didn't replace them they could very well be the culprit. Most folks would go ahead and do them when they are replacing the control arms, though - it only adds about $50 to the job, if I remember correctly.

I don't suppose you're an SCCA member, are you? There's an article in the most recent SportsCar about how to check if the frame is straight.