Do it yourself alignment: Question 4 Jason

[es3]

Haha, sorry to kind of dumb this down for myself, and ask questions. I've seen your walkthrough, and I can be fairly handy as to fix my own car (but to an extent ). Anyway, I just bought my "new" 300ZX T and it has a baaad alignment problem. Car veers strong right. The tires on the car are all around bad and will have to be replaced to pass inspection, and on the long ride home, my front right tire was worn pretty bald because of the alignment issue. Anyways, with my tires being bad as it is, I figure, why not give doing my own alignment a shot?

First off, just for the sake of me (please dear god, humor me), this is what I am adjusting, correct? (I feel the need to constantly double check myself before I mess up)


Second, you state that most people like a little "toe in", which I am assuming is meaning that the 2 front tires are facing a little in towards the center of the car, in comparison to perfectly straight. In your modifications list I remember it says "Rear 1/4" toe in, Front 1/8" toe out." How did you measure it exactly like that? Would you recomend me doing that to my tires, or was this done to your car for performance reasons, and for me to do this to my car would substantially increase tire wear?

Thanks in advance!

~es3

[Jason84NA2T]

Yeah, this was an autocross alignment I was and have been running. It makes the car turn in really fast and gives more ackerman steering angle from the front toe out. It did make the insides of the front tires wear a little faster than the rest of the tread.

Loosen that nut and turn the rod right by the left of the circle you drew in the picture. Be sure to set the alignment with the car at rest on flat ground. You probably know toe changes as you raise or lower the car/suspension.

Measure from the RIM to the string. You can figure this inch measurement in degrees if you like based on a 16" rim size.

[es3]

I'll just go for straight then I suppose. Thanks!

[Steve88t]

Having a car with just a hint too much toe-in can be freaking scary imho. I actually like a little out. But like Jason said, it tends to wear the inside edge. And lots of modified Z's already have some inside edge wear from having negative camber introduced to the front. (for the record mine does not)

[Jason84NA2T]

es3 wrote: I'll just go for straight then I suppose. Thanks!

Well you don't want straight or the car won't track correctly at all. Stock alignment specs are in the FSM.

[es3]

well how much toe in should I go? I don't go to the track :-P. I'm going daily driver for a year or 2 more. I might be pushing 250 (VERY optimistic), so I'll try to stick with the stock settings. This of course is considering that I can do it. It sounds too easy to have it just be that easy. haha. I'll check the FSM

[es3]

I'm outside trying to use my eye without too much luck. I figure it probably isn't helping that I've only got 2 jack stands. I think I'll try to mess with it for a bit longer.


I found this other method online. It seems a bit more accurate, but not too sure how to figure out which wheel needs the aligning.

I'm outside trying to figure out how to do it using my eye, 2 jack stands and some fishing line with no luck. I think I'll need those 2 other hack stands.

Here's a really easy, fast, two-person way to check toe. I use this on my X1/9, which hasn't seen a professional alignment rack since I bought it. Since I race it very actively, I consider proper alignment very important, but I don't want to spend $80 every time I make some kind of minor change to the suspension just to save myself about five minutes of work (30 seconds to check, a couple minutes to change it if it's wrong, another 30 seconds to recheck).

1. Drive the car to a level parking place. Ideally you want the car loaded as it will be when it is driven (e.g. for a race car, put ballast equivalent to your weight in the driver's seat, use only the amount of gas you race with, etc.). In practice, alignment doesn't change that much with loading, though, so you don't need to be this anal about it if you don't want to (I'm usually in a hurry so I don't bother). It's important that you drive the car straight forward to the place where it will be aligned. Once you turn the wheel, or jack the car up and then set it down again, you've changed the static alignment and the numbers you measure will be wrong.

2. (This part I got from Brad Martinson, and it's a really neat hack.) Get two straight pins and stick one into each front (or rear, if you're checking rear alignment) tire on the rear of the tire at some constant height H above the ground. H should be lower than the ground clearance of your car in the neighborhood of the wheels.

2(b). Jean-Yves Meunier came up with an improvement on Brad's method, which allows you to skip step 3:
In the tape measure I use, I piarced a hole slightly bigger than the pin heads at about the 6 in. mark (in the middle of the curvature of the tape).
You can now hang the hole on the tape on the pin head, this allows you to measure the distance without a helper (less nagging if the helper is your wife, more beer for you if it's your neigbour)

3. Have a friend hold one end of a tape measure against the tire starting at one pin. You stand on the other side of the car, pull the tape measure so that there's no slack and measure to the other pin.

4. Roll the car forward (not back, you'll roll over the pins!) until the pins now stick out the front end of the tires and are again at height H.

5. With friend, again measure between the pins.

6. The difference between these measurements is your toe.

Notes: you don't need pins (in fact, I seldom use them) as long as you can pick a repeatable place on the tread from which to measure (easy with A008's, difficult with Comp HR's, depends on tread pattern). An easy way to make sure the height H is constant is to use a piece of 2x4 as a marker (4" seems to be a good height on a lowered X1/9; on most cars you could probably measure somewhat higher). Measure as high as you can, because you get better accuracy that way (the tire sticks out more higher up, so you're measuring bigger numbers and your error is a smaller percentage).

Another note: after reading this page, Gerard pointed out that if you roll the car around during the process of checking or changing toe, you should end up rolling it forward, not backward, because if there's any slop in the suspension linkages, you want the toe optimized for the way the suspension slops going forward.

In practice, 1/32" is plenty of accuracy for measuring toe (you don't really know precisely what your front toe should measure to better than 1/32", do you? I sure don't, and I've been experimenting with my car's handling for quite a while. Optimal settings change according to tire compound, my mood, wear in the suspension bushings, how cold and wet the weather is, etc.).

If you want a bit more accuracy, then put the car on alignment plates. Get four thin squares (about 6"x6"x3/16", say) of smooth metal. Use them to make two sandwiches of metal outside, oil or grease inside. Now put one sandwich under each tire. If your metal plates are thick, then put something of equal height under the other end of the car, so it still sits level. Now you have an alignment plate just like the professionals use (only a lot cheaper) and you can turn the wheel, move the car, etc. without screwing up your static toe measurement. You can't use pins or roll the car back any more, though. [ George Tylinski suggests using waxed paper, which also avoids the risk of oil or grease contacting the tires. I haven't tried this yet, but it sounds like a fun idea. ]

[MrwassmanNA2T]

I thought you would want toe out in front and toe in in back. (not that it applies)