Here is the link:
http://forums.bimmerforums.com/forum...d.php?t=995556
Here is what I chopped out (and edited slightly) for you guys:
Q. What is the Stock B7 A4 Alignment Adjustability?
A: A stock B7 A4 has the following adjustments - front toe, rear toe and rear camber.
Q. Can only certain shops align my B7 A4?
A: There is nothing special about aligning your B7 A4. But the factory specs are terrible and you can forget about them.
Q: Can I just take my car into a shop and ask to get it aligned?
A: Only if you dont care about performance and tire wear.
Q: What the hell does that mean?
A: If you bought a B7 A4, you obviously are looking for performance (or if you bought it for image, status, pimping, flossing, hardparking, etc, please GTFO! ). The Audi factory specs care nothing for performance or tire wear, only for safety and a low # of lawsuits. YES I AM SAYING THAT THE Audi FACTORY SPECS WILL NOT ONLY GIVE YOU POOR HANDLING AND PERFORMANCE, IT MAY ALSO WEAR OUT YOUR TIRES PREMATURELY.
Q: Ok, so what is a good performance alignment for the street with good tire wear?
A: Here are the specs:
Front
Camber: -2.5 deg (per side)
Toe: 0 (or 0.10 to 0.20 deg total toe in for mostly highway driving)
Rear
Camber: -1.5 to -2 deg (per side)
Toe: 0.20 total toe in (IIRC this is 1/8" total toe in)
Q: Can I get a good Performance Alignment for the Street with stock adjustments?
A: NO! You cannot get a good performance alignment for the street with a bone stock B7 A4, or even with a modified suspension, without front camber adjustment. You need some form of front camber adjustment that doesn't come stock.
Q: Why do I need front camber adjustment?
A: Here is the short explanation (long explanation explained later)...your B7 A4 came from the factory with an alignment that gives the rear tires more grip than the front. This means, when you are going around a turn (say an off ramp) and you are at the limits (tires are squealing), your front tires are giving up and the car does not turn. That is much safer than if the rear tires gave up first and you are now spinning around. But when the front tires give up long before the rear tires, you are giving up a lot of cornering ability vs. a car that all 4 tires give up at the same time. And a car that wont turn feels like crap.
Q: How much negative camber is safe to run on the street?
A: Up to -3 deg per side is safe to run on the street, but you will likely see some inner tire wear over time. (I used to run -3.4 deg camber per side on the street, with about 0.20 total toe OUT, and I got inner tire wear...about 2/32 more than the mid-outside of the tire). Now I run -2.5 deg camber per side and 0 toe on the street, and max out my camber plates negative at the track only.
Q: Wont too much negative camber kill my tires?
A: Negative camber does not kill tires. Negative camber plus excessive toe (in or out) causes inner tire wear. Toe (in or out) in effect forces the car to "drag" the tire down the road, where 0 toe lets the tire roll down the road. Make sense? Negative camber will cause the tire to roll on the inside of the tire, but negative camber plus excessive toe will drag the inside of the tire down the road causing bad inner tire wear.
Q: So why are the insides of my rear tires worn after I got a factory alignment?
A: Because factory specs call for lots of negative camber and LOTS of toe in. Very safe but bad for tire life. (Another cause for bad rear tire wear is worn out trailing arm bushings (RTABs) giving you dynamic toe changes.)
Part II
Q. How does camber affect performance?
A. To maximize cornering force from your tires, the tire must be square on the road during a corner to achieve max grip. If your car had zero camber (all tires square to the road when driving straight), as soon as you turn, the body will roll to the outside, and the outer tires will roll only on the outsides of the tires. Thats why if you ever drove a car with stock alignment hard in turns, you'll see the outsides of the tires worn.
Q. What is a proper alignment procedure?
A. Before you get your car aligned, you should know what will happen. The shop will put your car on an alignment rack, and put sensors on the 4 wheels. Some racks have a hard time with very low cars, or cars with spoilers (the Beissbarth rack). It would be good to place weights in the driver's seat equal to your weight. But again, not critical.
The tech should start at the rear of the car, where he can adjust toe and camber. To adjust camber there is an eccentric bolt where the lower control arm bolts to the spindle (or wheel hub, correct term?). Anyway, once this is loose, it can be turned to adjust camber. It has a cam shaped profile, the base circle of the profile gives the most positive setting, the high end of the "cam" gives the most negative setting. Once the settings are reached, the tech will re-tighten the bolts, (if he's good, he'll do it carefully so as not to affect the positions when tightening, which you'll see when the numbers don't just quite match).
In the front, all that can be "adjusted" is toe. This is just a matter of loosening the tie rod jam nut, and then adjusting the tie rod length, and then tightening down.
Q. What should I do before I get an alignment?
A. Know what you want from the car. Know what settings you want, or the shop will give you factory settings. Do you want the best performance with good tire wear? Then you need to address your front camber issue.
Q. How does toe affect performance?
A. Toe behaves similar at either end of the car. Toe in will stabilize the car, making it track straight and not want to change direction. Toe out does the opposite, makes it twitchy, and want to change direction quickly. A car is more responsive with toe out, but less stable.
FRONT Of CAR - Toe-out in the front lets the car turn in nicely, but may "tramline" down the road (finding grooves and irregularities and following them). Toe-in front makes the car hard to turn and want to "push" or understeer (BTW this is what Audi recommends!).
REAR OF CAR - Toe-out in the rear is pretty dangerous for RWD cars (or rear wheel bias like Quattro), makes the car want to spin, especially under hard braking. Toe-in rear will keep the rear stable, and (here is the key) allow for you to put power down as early and as hard as possible without wheel spin. More is not always better, racers will always adjust these settings till they get it just right. For the street, the suggested settings will let you set-it-and-forget-it.
Q. What is a good track/autox alignment?
A. Most track guys already know what to do here, but for general FYI, a good baseline is:
Front
Camber: -3.5 deg per side
Toe: 0 (0.10-0.20 total toe out for autox)
Rear
Camber: -2.0 to -2.5 deg per side
Toe: 0.20 total toe in (IIRC this is 1/8" total toe in)
You'll notice it is just slightly more aggressive than a good street alignment. Any more than -3.0 deg camber and 0.10 toe (in or out) per side can lead to inner tire wear with lots of highway driving.
Some race cars (on race tires) will run even more camber. For race cars, suspension and weight (and usually the track) always play a role in alignment.
Here is my car on street tires with -3.3 deg camber front, 0.10 total toe out, and -2.5 deg camber rear, 0.20 total toe in.
Notice as the car rolls, the tires on the ground are square to the road.
Q. Why believe the author?
A. You don't have to. I'm not part of a professional race team or anything. But I've done a lot of research, a lot of tuning, and a lot of listening to faster racers. I've had my M3 since 2004. Since then I've learned to develop and setup my M3 competitively for autox and track. In 2005 I was mid pack in my autox class. In 2007 I was beating (and getting beat by) national trophy winners. Also in 2007 I started doing time trials with NASA, and held track records at VIR Full and North Course (which will be improved upon!), and got 3rd place at Redline Time Attack - Summit Point (behind two superb BMW drivers). Also became a certified NASA Instructor Feb 2008.
I also drive my car on the street, and can't afford uneven tire wear. I DD, autox, and do track events all on the same tires, so they may not last more than a year, but they are usually worn evenly. I have worn tires unevenly, and it was because I was running the wrong alignment settings (usually too much toe!)
In 2010 I've won all but one NASA MA Time Trial events (I lost one to the Continental Challenge RRT E90 328) to claim 2010 NASA MA TTC Championship.
I competed in the GRM Ultimate Track Car Challenge in 2010 and 2011.
In 2011, I now hold the VIR lap record (2:11.1) and the NJMP Thunderbolt lap record (1:32.3), and held the Summit Point lap record for 1 lap (1:22.1) in NASA
s TTC class.
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Originally Posted by CorneliusRox
Hope this helps people understand!
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