DIY Alignment?

Have any of you ever tried this? It honestly seems pretty straight forward to me ... especially if you have camber plates.

String the car and set the toe ... really easy if you are going for 0º.

Set the camber to something conservative in the front with the stock adjustments ... set the back to where you want it ... maybe around -1.2º to -1.5º. Then, dial in the front using the plates ... I'm aiming for -2.5º or so. If the process is easy enough, I might dial in -2.8º or -3º for auto-x.

Camber gauges range from around $30 to well over $400 depending on how many doo-dads you want ...

Anyway, I'm researching the topic and I'll report back when I get some good info ... alignments are expensive because of the equipment the big shops use and very few of them really know the ins and outs of alignment specs anyway. I would feel more comfortable just doing it myself and knowing it's right.

I've done string alignments on my bikes, but it shouldn't be much harder.

I found a few useful pages about the procedure and inexpensive ways to measure the camber ...

http://www.c-speedracing.com/howto/alignment/alignment.php - This one uses a really basic string method that might not be too accurate since it's based on the car's body and not the chassis or suspension. However, I like the camber tool he uses.

http://www.quadesl.com/miata_alignment.html - This guy goes all out and has made his own super accurate camber gauge. He also goes in depth in to how to correctly fine the center line of the chassis and how to measure from that. Using these methods will definitely render an accurate alignment. His water level technique should work nicely as well.

http://racecarstuff.com/?page_id=2 - This one is a little hard to follow since there are no photos and the explanation is a little technical. However, it does contain some good info.

http://www.veloandy.com/pics/alignment/how_to_align_your_car_at_home.htm - This one has some really good info on making your own camber gauge from very basic materials and also gives you the math to determine your current and desired camber angle. However, I'm not sure I like his toe measurement device since it's measures toe based on the opposing wheel. Maybe I just don't completely understand his method.

I've also seen home made camber gauges that use a standard angle finder for measurement. I've got one of these at the house, but I'm thinking the resolution just isn't good enough for the job.

Anyway, here are the basics of the DIY alignment ...

1) Make sure the car is absolutely level. If it's not, your camber measurements will be worthless. Use a water level for this and measure a static point on the wheel. The uppermost or lowermost point on the wheel center cap should work for this.
2) Inflate your tires equally on opposing sides of the car and to the pressure you plan to race with. If your tire pressure is off, so are your measurements. This also applies to professional alignments ... the tech at a shop won't check this for you.
3) Measure toe from the centerline of the suspension/chassis and not from the body. The body of the car is likely not 100% centered on the chassis.
4) Set the camber before the toe. Camber setting can affect toe, but toe adjustments don't really affect camber settings.
5) After making an adjustment, rock or roll the chassis to help the suspension settle. This will help ensure consistent accuracy.
6) Make sure the rims are true ... or at least that the places you take measurements from are true. A bent wheel will not give accurate measurements.

Getting an Accurate Toe Measurement

Alrighty ... I spoke with a couple of engineers at work and came up with a reliable way to measure toe settings. Here is a diagram I put together ...



Go ahead and level the car and properly inflate the tires before getting started on this ...

(So Far) You'll need:
a car
tape measure
some type of heavy-duty string ... Fishing line, surveyor string
hanging line level
jack stands
square of some type
a long straight edge (if your square will not suffice)
opaque tape
marking utensil
plumb bob
level
ruler that measures in 1/32
some shims to level the car ... planks, tiles, etc.
long clear tube (to make a water level)


Chassis Centerline

First, you have to find the centerline of the chassis. Do this by taking measurements from suspension mounting components or something else easily found that's mounted directly to the chassis. I suggest measuring a few different locations to ensure accurate measurements.

After making measurements and locating the chassis center in the front a rear of the car, make a couple of permanent marks on the undercarriage so you can use these same marks and bypass this process in the future.

Now you need to string the centerline of the car. Just attach a string to some heavy object at either end of the car and pull it taught. Align this string with the centerline marks you made on the undercarriage. Now you have a basis for your measurements.

You could also simply hang your plumb bob from the marks on the undercarriage and mark a centerline on the floor, but you'd need a long straight edge for that ...

Triangulating the Parallel

This part should be a little easier since you aren't working in the air, however it requires some math and some time.

You'll need a plumb bob and some way to hang it above your centerline string (a dial indicator holder is used in one of the links in the previous post). Any sort of static object that will let the bob hang freely should work for this. We'll be marking the measurements on the floor, so get some tape ready. Marking on the tape will make for easier cleanup.

Take your hanging plumb bob and align its string with the centerline. This will be your first measurement point for the triangle, so be sure to leave a enough room for your triangles to clear the wheels (you have to use the hypotenuse to check your angles ... it needs to be unobstructed by the wheel/tire). When you've got your point on the garage floor, lay down some tape and mark it. Repeat this process about 12" away and then connect the 2 points with a straight edge. This can be done at a point on the centerline that is outside of the cars dimensions for easier measurement.

Now that you've got your centerline in a usable location, you can use you square to make a perpendicular (90º from the centerline) line to the outside of the wheelbase. You will use the mark created in this process to align your parallel string for toe measurement. You want your mark to be close enough to the outer edge of the wheel that your ruler can cover the distance between the wheel and the toe alignment string. My ruler is 6", so a 3" to 5" distance from the wheel to the string would be ideal.

Now, if you trust your square you are basically done with measuring for this end of the car ... you can simply repeat the process for the opposite end of the car and set the string. However, not all squares are true ... especially if they have some age on them. Checking the angle of your perpendicular mark is fairly easy ... you need to use the 3/4/5 rule.

Basically, you can use simple math to check the angle as shown in the illustration. Here is the process ...

1) Measure the distance of the perpendicular line you created from the centerline to the outer toe measurement line.
2) Divide that measurement by 4.
3) Take the result of step 2 and multiply it by 3.
4) Measure that distance (result of step 3) on the centerline, starting from the same point used to measure the parallel.
5) The end of the line you just created will be the second point needed to measure the hypotenuse of the triangle. Measure the distance between the end of this line and the point created for the parallel toe measurement line. This measurement should equal the result of step 2 multiplied by 5.

So, an example is in order ...

The distance from the centerline to the parallel toe measurement line is 4' ... 4 / 4 = 1

Multiply that by 3 ... 1 x 3 = 3

Measure out 3' from the 90º angle you used earlier ...

Hypotenuse = 5, and therefore you have a perfect right angle and therefore accurate toe measurements. I suggest doing this at least once, even if on a smaller scale simply to verify the accuracy of your square.

Of course, you can use any multiples of 3, 4 and 5 in feet, inches, centimeters, millimeters or any other method of measurement you choose.

Stringing the parallel toe line

Stringing this line is pretty easy. You need your string (of course), 2 jack stands, you plumb bob and whatever you're using to hang it with and a line level (the kind that hangs on the string.

Your goal is to align this string, taught and level, with the center of the wheel. It doesn't have to be exactly center on the wheel, but the closer the better and you will have more accurate measurements.

First, go ahead and tie your string around the heads of the jack stands and place the 2 jack stands at either end of the vehicle past the 2 marks you made in the previous section. You will be aligning this string with those 2 marks.

Get the string pretty taught between the jack stands by sliding them away from each other. They should be able to hold up against a bit of tension from the string. Now, go ahead and eyeball the string height to the center of the wheel and get it nice and level using the line level.

Now, position your plumb bob just above one of the marks you made based on the centerline of the car. All you have to do is gently align the string on the jack stands to the string on the plumb bob. Get as close as you can without moving the plumb bob. Now, repeat on the opposite end of the car. I also suggest repositioning the string aligned to the first mark since you changed the angle of the string slightly from the first measurement. Also, remember to align this string to the same side of the plumb bob string every time to keep your measurements perfect.

Okay ... I was under the car the other day re-installing my front cross brace and found something neat ... both front cross braces are mounted to identical places on either side of the car. This means that you can remove the cross braces and use them to measure the front centerline of the car.

I made some measurements on both bars and carefully scratched off the paint with a saw to mark the center. I lined them up to verify and they were just about perfect ... maybe 1mm difference in the marks.

I've got some pics that I'll post, but the difference in length of the bars is 8cm and after lining up the centerline marks on both I had an almost exact 4cm difference at each end. The back isn't going to be as simple and I'll need a hand with it, but I've got a few measuring points in mind. I'll have pics of that as well.

Trying to get this done on Sunday ... Yes, aligning my car on Easter. I'll post pics and thoughts afterward.

Well, I attempted this yesterday with the help of Ervin and a couple of guys from Alabama Racing Scene. We managed to get the front aligned but didn't have time for the back. It was definitely a learning experience though.

I was able to get about -1.6º from both sides on the front and the toe is set fine. The stock adjustment just doesn't really allow for fine tuning. -1.6º it a bit better that the -.7º or so I had before.

The toe is good, but the car does try to wander a little with 0 toe. Under acceleration it's really true and straight ... I hit the throttle and went through 2nd with my hands just off the wheel with no pull what so ever.

Here are some things I learned ...

Using a laser rather than a string has it's faults ... and using a cheap laser has even more faults. It's a little harder to align than a string and may not actually be level while sitting on your garage floor. Also, if you use a laser, try to get one that has a nice, broad spread but keeps the line precise and constant across that spread. Before my next attempt at aligning, I hope to get a better laser and build an adjustable stand for it.

If you are building a camber gauge, use a board about 30" long or longer and notch it to clear the fender. My scale was based on a 23" high triangle and the resolution was still pretty low ... 1cm for 1º of camber. That makes for easy measurement (1mm = .1º), but better resolution will increase accuracy. Also, use a fishing string for your camber gauge with maybe a fishing weight on the end. I used surveyor string and a couple of washers to weight it. It worked, but I'm sure the accuracy wasn't quite there because of the width of the string.

When setting the toe, make a few turns on the tie rod and then re-center the steering wheel. Since the steering wheel has less resistance than the tire, your adjustments will just spin the steering wheel if you don't keep an eye on it. You also don't just want someone inside holding the wheel since it might shift a little when they let go. You just want to turn the rod a few times and then bump the steering wheel left and right a few times to transfer the adjustments to the wheel.

i plan to do a DIY write up on this soon. I hope to take pics when I do it again and I'll add those to the DIY later.