Do It Yourself Alignment Tips

Wanna try your own alignment? It's not too hard, and after a couple of times of doing it, you can do a check in under 30 minutes.
The steps I outline here allow you to check toe and camber in a pretty repeatable way (within 0.5mm toe, 0.1 deg camber) with tools that cost a total of maybe $50.

Disclaimer: Any alignment you do with reference to this page is your work. I use this proceedure on my own cars with no problems. So if you attempt to do the alignment, don't blame me for any problems that may arise.

With that out of the way, let's get started!

It's important to make sure the area you are checking the alignment in is reasonably level. You can do this my running a string from 2 jack stands that are placed approximately where the car wheels are. Measure from the string to the floor very close to both jack stands, and make sure the measurements are even. Then take a level, and line it up with the string to see how level things are. If that's a pain, use a nice straight 2x4 across the stands. It's much easier to check the level on the 2x4 too.

Now that you have a nice level area, drive the car in. Do so as straight as possible, as turning the wheel even a little will pull/push a tire a bit and affect your alignment. If you have to turn, just make sure to bounce the car a good bit before running the check (I bounce from the door rails).

TOOLS:


Toe: tape measure	Toe: length of string	Toe: jack stands

Camber: modified level	Camber: digital caliper

Here's the tools that you'll need to measure toe:

Tape measure: Preferably with mm graduations. Used to measure toe between the wheel and parallel line.
String: Nothing too thick, or too thin. I used a kite-type string. Used to create the parallel line to measure against.
Jack stands: Raise them so one of the notches is even with the center of the wheel. If you want to do all 4 wheels at the same time, you'll need 4 jack stands. The jack stands are used to hold the string taunt along a parallel line down the side of the car.

Here's the tools that you'll need to measure camber:
Modified level: To check camber, you need to have a perpendicular plane to compare the wheel angle too. The level is used to find the perpendicular plane.
Digital Caliper: I have this fancy digital one (from Harbor Freight - cheap). A dial one will work fine too - but the digital is easier. Used to measure distance between the top of the wheel and the modified level.

I also recommend that you get some 8" or so lumber and ramps so that you can get underneath the car to access the adjuster bolts. It will make it much easier than jacking the car, adjusting, lowering the car, and rechecking. This is mainly a pain for toe, as you'll have to recheck your parallel lines if you jack up the car.

CHECKING TOE:


Tie the string around each jack stand at the notch.	Use a brick to hold 'em down so you can make the string taunt.	2 stands to a side, with string between them.

First off, set things up so you can measure toe. The concept here is to use the jack stands to hold the string nice and taunt between them. You line up the string parallel to the car, and can measure the front/rear of the rim as an indication of toe.
Before getting started, park the car with the steering straight. When you pull into your work area, drive in forward, and do not allow the car to roll backwards at all. If you've just jacked up the car, bounce the car a bit to settle the suspension.
Grab your jackstands, and raise them so the top notch is even with the center of the wheel. I use the notch as a string guide.
Set your jack stands about 1 foot forward of the tire (at the front of the car), and 1 foot rearward of the tire (at the rear of the car). Both jackstands should be about 6 inches outward from the car. 2 jackstands per car side. Wrap the string tightly around the jackstand (make sure it can't slide out when pulled), and wrap as shown in the first picture (it's best to wrap so the string going along the car is in the notch).
Get the string pretty tight as you wrap around the jackstand at the other end of the car. Repeat for the other side of the car.


I always measure 100mm from the FRONT hub center.	For S14, measure 105mm from the REAR hub center (S13 is 102.5mm)

Measure at the rim towards the front of the car. (76mm here)	Measure at the rim towards the rear of the car. (75.5mm here)

Most DIY alignments recommend you find the centerline of the car. That's great, but is a pain in the backside. As an easier alternative, I use the hub centers as the point of reference for setting up the parallel string. It's best to have matching front/rear center caps here, and to also know your car's track front/rear. The 240's have either:

S13: 57.7" (F), 57.5" (R)
- difference of 0.2" total, front to rear
- difference of 0.1" per side * 25.4mm/inch = 2.5mm

S14: 58.3" (F), 57.9" (R)
- difference of 0.4" total, front to rear
- difference of 0.2" per side * 25.4mm/inch = 5mm

If the track in the rear of the car is less than the front (as the 240 is), INCREASE the distance to the string in the rear.
If the track in the rear of the car is greater than the front (like a Miata), DECREASE the distance to the string in the rear.

To be consistent, I always measure the distance from the front hub to the string as 100mm, and then adjust the rear as needed (+2.5mm = 102.5mm for S13, +5mm = 105mm for S14)
So a parallel string setup along the side of a S14, would measure 100mm to the center of the hub in the front, and 105mm to the center of the hub at the rear.
Now that you have the parallel line, take 2 measurements per wheel. Measure the distance from the rim to the line at the front most part of the rim and at the rearmost part of the rim. Try to keep the tape measure as perpendicular to the parallel line as possible. Look over the top of the tape down on the line to make sure you are not looking diagonally across the tape and line. Take the two measurements:

rear(mm) - front(mm) = __mm toe

Example:

75.5mm - 76.0mm = -0.5mm toe in.

Subtract the measurement from the frontmost part of the rim, from the rearmost part of the rim. Negative means you have toe in. Positive is toe out. To determine the toe angle, first determine your rim size in mm. You should measure this from one edge to the other (my 17" rim is 18" from one measured point to the other). 18 in * 25.4 mm/in = 457.2mm. Use this to determine angle like this:

inverse tan( __mm toe / __mm rim size )

Example:

inverse tan( -0.5mm toe / 457.2mm rim ) = inv tan( -0.0011 ) = -0.063 deg

Same as before - negative angle means toe in. This measurement is for one side only. Take the measurement on both sides and add them together to get total toe for the car. Example:

left measured toe: -0.5mm
right measured toe: -1.0mm
total: 1.5mm of toe in

Adjustment to toe is usually done (in the front of the car) with the tie rod ends. Remember to re-check steering wheel straightness, and to wiggle it a little (always going back to perfect center) whenever you adjust the tie-rod ends.

CHECKING CAMBER:


I put my foot on the bottom to ensure it's tight to the rim.	Measure from the rim to the bar, with the level even. 0.863in = 21.92mm	Diagram of the measurements and calculation needed.

Checking camber is a heck of a lot easier than toe. The main tool I use is a slightly modified level. I cut a piece of aluminum square bar stock to match the height of the rim. This is not the listed wheel diameter (which is the diameter that the tire is mounted on), but the wheel diameter plus the size of the mounting rim that you will measure against. In my case, a 17" wheel is really 18" (457.2mm) from top to bottom.
I just taped the bar stock with electrical tape, so that it could slide a bit on the level. This is good because I want the end of the bar to sit on the lower part of the wheel, not the tire. So I slide the bar so the level can sit on the ground while the bar sits nicely on the lower rim.
With the level against the wheel, place the digital caliper between the rim and the level (as shown). I really pull the level out about 1.5" or so to start with, and then slowly push it in (which compresses the caliper too) as I watch the bubble in the level. When the bubble is perfectly centered, get the reading from the caliper (0.863in = 21.92mm in the pic).
The camber angle is easily calculated with the formula:

inverse tan( __mm measured / _mm bar length ) = __ deg camber

Example:

inverse tan( 21.92mm / 457.2mm ) = 2.7 deg camber

Or, if you like using inches (I use inches when measuring camber):

inverse tan( 0.863in / 18in ) = 2.7 deg camber

MAKING IT A LITTLE EASIER:

(hopefully)

I received an email a little while ago from Almir Delic. He had come up with an Excel spreadsheet to help him calculate what he needed to get the toe settings he wants. It was a great idea! So I took his thoughts and expanded his original Excel sheet. I've included it here for you. Fill in the red fields with your known values, and the green fields are calculated for you to measure on the car. I hope it makes things easier - but there are a lot of fields to consider.

Here's a field-by-field explanation. If the field wants mm, but you have inches - simply multiply by 25.4. If the field wants inches, but you have mm - then simply divide my 25.4.

TOE:

"inch diameter wheels" (red) : enter the diameter of your wheels, in inches.
"mm front track" (red) : enter the front track of the car (wheel-center to wheel-center) in mm. Can usually be found on Carpoint
"mm rear track" (red) : enter the rear track of the car (wheel-center to wheel-center) in mm. Can usually be found on Carpoint
"mm front rim plane to centercap" (red) : looking in the plane perpendicular to the ground, and flat with the outside of the wheel, most wheels have a rim that sticks out further than the centercap. Put the level across the outer rim, and measure how deeply set the centercap is in mm. If the centercap sticks out past the rim, this value should be negative.
"mm rear rim plane to centercap" (red) : looking in the plane perpendicular to the ground, and flat with the outside of the wheel, most wheels have a rim that sticks out further than the centercap. Put the level across the outer rim, and measure how deeply set the centercap is in mm. If the centercap sticks out past the rim, this value should be negative.
"mm to rope from front center" (green) : measuring from the front wheel centercap to the string parallel to the car in mm. Move the string such that it meets this value. (Note that moving the rope on either end requires rechecking at the other).
"mm to rope from rear center" (green) : measuring from the rear wheel centercap to the string parallel to the car in mm. Move the string such that it meets this value. (Note that moving the rope on either end requires rechecking at the other).
"deg of FRONT toe in (+) or out (-) PER SIDE (red) : toe is measured different ways - either with an absolute measurement (such as X mm of toe) or with an absolute per side measurement (such as Y mm of toe per side) or using an angular measurement (such as Z degrees), or using an angular measurement per side (such as Z/2 degrees). The best is using the degrees (or in our case, degrees per side - which is just total degrees divided by 2), since the mm/inch measurements change depending on how far from the wheel center you measure them. For TOE IN, put a positive angle, and for TOE OUT, put a negative angle. If you have per-side or overall toe absolute measurements, simply adjust the angle until the boxes for "mm of TOTAL toe in (+) or out (-)" or "mm of PER-SIDE toe in (+) or toe out (-)" match what you want.
"deg of REAR toe in (+) or out (-) PER SIDE (red) : toe is measured different ways - either with an absolute measurement (such as X mm of toe) or with an absolute per side measurement (such as Y mm of toe per side) or using an angular measurement (such as Z degrees), or using an angular measurement per side (such as Z/2 degrees). The best is using the degrees (or in our case, degrees per side - which is just total degrees divided by 2), since the mm/inch measurements change depending on how far from the wheel center you measure them. For TOE IN, put a positive angle, and for TOE OUT, put a negative angle. If you have per-side or overall toe absolute measurements, simply adjust the angle until the boxes for "mm of TOTAL toe in (+) or out (-)" or "mm of PER-SIDE toe in (+) or toe out (-)" match what you want.