my car pulls to the right a lot.....but on some roads it pulls to the left. I had a alignment done at a dealership and it didn't fix it, so they said to get new tires and I did that but it still does it. Any advice as to what could be causing this would be great. Thanks

 

A little more information is necessary to do any kind of analysis.

What tires are you using (all four corners)?

What wheels are you using (sizes and offsets)?

Does the car have lowering springs?

What specifications did the aligner use?

Did they perform a full thrust angle alignment or simply a front end alignment?

Are the rear LCAs intact and solidly mounted?

Any noticable play or looseness in the steering when sitting still with the engine off (steering wheel unlocked, of course)?

 

all the tires are pacemark and put on at the same time. The rims are all stock 15 inch. I'm not sure of the specs on the alignment but I payed extra so they could do every kind of alignment and adjustment as needed. The wheel has no play in it. I got told that the unibody could be bent, but then it would only pull toward one way right?

 

Big mistake. They'll line it up to stock specs, and it'll wander like hell and have no definite center feeling to it with those specs.

Take it someplace else, and have them set it as follows:

Left - -.5-1.0° camber, +4 caster (that's negative camber, positive caster)
Right - -1-1.5° camber, +4.5-5 caster
Toe- 1/32" inward

My guess is, it will drive somewhat different set up like that. Stock camber is positive, and caster is much lower positive numbers, both of which will make the steering feel very light and cause the car to be drifty with wide tires.

 

Those are probably the right specs to use. What I've had from various sourcers is about the same, depending on intended use:

Street Use
Caster - L +4° / R +4.5° - Camber - L -.5° / R -.5° Toe 3/32" IN

Hard Street Use
Caster - L +5° / R +5.5° - Camber - L -1.0° / R -1.0° Toe 3/32" IN

Drag Racing
Caster - L +4° / R +4° - Camber - L -0° / R -0° Toe 1/32" IN

Road racing
Caster - L +6° / R +6° - Camber - L -1.75° / R -1.5° Toe 1/8" OUT Short Course - 1/16" IN Long Course

 

Personally, I use a frame shop instead of the dealership. That's where the dealer sends teh "tough" ones, anyway. Strut cars are a bit different, and can be a little tricky to set up properly. The lack of an upper swingarm (and the resultant shorter arc to control camber on compression) requires some different methods. Too many shops try to just "set the toe and let her go" since most people don't know any better.

Caster is the "black art" of alignment angles, and while it doesn't affect wear when the car is traveling straight down the road, it can certainly affect tire cornering wear, handling, and feedback.

On a car with front struts, like ours, caster that is too low (more negative) will tend to eliminate any negative outboard wheel camber on turns. This can cause unnecessary outer wear on both front and rear tires because of the unequal weight transfer on hard cornering. Even if you are not pushing the car hard in corners, the tread wear may appear at least on the front end. It also can make the car feel loose in cornering, since the rear tires are taking more of the side loading from excessive weight transfer from the front end. More negative caster does help (a little) on bump steer, but the gains there are wiped out by the lack of overall control in hard cornering on normal surfaces. I would suggest setting the caster as high as you can within the specified range, or just short of the point of losing high speed stability.

Camber should be 0° or less, even if you don't push the car hard through the corners. Again, on a front strut vehicle like ours, the lower swing arm arcs tend to turn the camber more positive on the outer wheels under cornering loads (just the opposite of dual swingarm suspensions with a shorter upper arm), so setting a little more negative can have a beneficial effect. It will also tend to put more weight inboard and provide a better roll center of the entire body.

An important factor in all of this is ride height. Just like harder cornering, sagging springs will greatly affect the camber angle on strut equipped cars, so is important to consider when determining the camber you want. It may be advisable to weight the car as it would normally be during driving before adjusting any steering angles. If that means loading the fuel tank full and placing a 200 pound weight in the left front seat and a 100 or so in the right front, then try to convince your frame shop to do that. Sagging springs, or even new lowering springs can cause the swingarms to be positioned at a point in their arcs where all travel from compression is inward only, creating positive camber right away and causing great difficulty in achieving a satisfactory camber setting. If the lower end of the wheel turns inward as soon as the suspension is compressed, camber will not maintain at the set angle as desired for even a small part of the suspension travel.

That alone is a great reason to throw away the lowering springs and change to dropping spindles if you want to lower the vehicle (the ONLY correct way to do it on a strut suspension).

It is also extremely important to have true tires when aligning the steering. Worn tires can cause unpredictable loading of the suspension and make correct adjustments almost impossible.

 

Would hard street use cover the best setting for streetable racing and handling or should you set it different for having the best of both? What are the real differences between these on the street:

Street Use
Caster - L +4° / R +4.5° - Camber - L -.5° / R -.5° Toe 3/32" IN

Hard Street Use
Caster - L +5° / R +5.5° - Camber - L -1.0° / R -1.0° Toe 3/32" IN

 

The more negative camber will tend to wear your tiresa a bit faster, but also provide a bit better conrering roll control.

The more positive caster will help camber on turns, and provide a stiffer, more responsive wheel, but negate some of the self-centering tendencies of the steering. You'll have to steer it both into and out of turns.

 

ok lets says I go and get more of this alignment work done and it still does this, then what could it be?

 

Thanks Vader.

 

And that, my friends is why Vader got his own board.

And now, i head to the shop...but one question. Are those values specific to that vehicle? or are they universal and i go in and say "i need such and such settings" (assuming its off)

 

You cannot make that assumption. Those specifications are for ThirdGen F-cars only. Other cars with rear drive and front strut suspensions may be similar, or may be way off. Front drive cars would likely be significantly different.

Specifications for cars with dual swingarm front suspensios are significantly different, and those suspensions act quite a bit differently than front struts. The inherent tendencies of dual swingar suspensions are quite the opposite from struts in caster and caster-induced camber on turns/cornering, and bump-steer tendencies. If you have a different vehicle, treat it differently.

 

And if I should have my own board, other in this thread should have their own site. Let's all give a little credit where it's due.

I only remember what I can from listening, observing, and learning. Somtimes, learning the hard way also provides valuable lessons. Anyone can do that.

 

Well i meant universal for the f-bods. Otherwise id be asking elsewhere. Go fish it would be universal in regards to the f-bods, specifically the third gen, on TGO.

 

Yes, Vader is incredibly knowledgable, but there are lots of people like that in lots of different ways and they deserve credit too. A joke for a day has nothing to do with what actually is, it really was to exaggerate something that's been going on for a long time here that almost all of us have done, ask help from specific people instead of putting it out there for everyone.