Subject	Do-it-yourself alignment (Suspension 401)
Posted by	Technomancer on August 31, 2005 at 12:28 PM
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Message	I have just published the following on my webpage. Any updates or corrections will appear on that site. This is a really long document because it is meant as a kind of textbook. Enjoy, and feel free to email me with comments! Suspension 401: Do-it-yourself performance alignment of your car's camber, caster, and toe angles by Dr. John Krane Syllabus Intro: you don't need expensive equipment Align just the camber if full alignment is too much for you Full equipment list, with recommendations and estimated costs Level the car first, be safe! Detailed procedure for adjusting Caster, Camber, Toe Example of my car's alignment, discussion of angle changes over time Welcome to Suspension 401, a senior-level course in my fictional little automotive university. For this class, I assume you already know the basic material (covered in the 101 course, etc.) but if you don't it is easy enough to find online. It's best if you know the material from all the 100 and 200 series, but you can get much of it on your own, or from context here. 401 covers the most commonly adjusted alignment angles, and it is necessary to master the basic alignment procedure to graduate from my fictional little university. The purpose of this write-up is to show the hobbyist how to align their car with simple real-world tools and equipment. Few of us have laser alignment equipment with turn plates and scales, nor would we want it. It's too expensive, too hard to store, and (get this) for practical use the precision isn't any better than what you will learn here. Furthermore, you can't take all that stuff to the track, so even if you had it, you might want to learn the following so you can make adjustments on race day or any time you think you might need it. There are many pitfalls in this procedure, and many alignment equipment vendors interested in your dollars. This write-up will show you what equipment is necessary and how to use it with a minimum of false starts. You must decide for yourself if the extra convenience of professional (-ly priced) equipment is worth the expense. Remember to work as consistently and repeatably as possible. The equipment is only as accurate as you are careful. A few weeks after your alignment, I recommend rechecking as many of the angles as you can, and checking parts for tightness. If you recently bought new suspension springs, they will compress quite a bit over the first month or two, with most change happening in the first few weeks, so pay special attention to camber changes. (I found my new springs compressed at different rates, see "case study" at the end of this document.) If all of the following seems to be too much, consider buying a digital camber gauge only. Have your alignment done for you and do camber tune-ups from time to time. If your original alignment is done to your satisfaction, you will derive more than 90% of the benefit by keeping camber where you want it. Avoid bubble gauges, especially if you will do quick-and-dirty camber adjustments on non-level surfaces. (Your garage floor is not level unless you shim the tires.) The digital gauges can be calibrated for the ground's tilt at each wheel, the bubble gauges cannot be. Special Tools/Equipment Required straight wheels! If your rims are all bent up, you will never get good readings with your equipment. To state another obvious point, when you take your measurements, don't let wheel weights interfere with your gauge or your measurments will be invalid. You will probably also need a strip of straight wood to make a flat surface between the left and right edges of the wheel. This "bridge" strip is described in the Caster section. I made mine from scrap wood. digital camber gauge (also called a camber/caster gauge) With modern electronics so cheap, there is no reason to purchase an analog (bubble) gauge. The money you save on a cheap-o bubble style gauge is not worth the difficulty to recalibrate it if it were ever dropped. The digital gauge's calibration mode also corrects for non-level ground, for use "in the field". Find a nice digital gauge like the one made by SMART. This is the gauge used in the photos below. Important: if you have fenders on your car and you choose this gauge you must buy the extra-long pegs or the tool's frame will interfere with the car's fender when the wheels are turned. (My price was $250 + $15 for the longer pegs. I splurged and also bought the "hands free" crossbar, which is convenient but not necessary.) toe gauge (or steel machinist's ruler) I recommend a gauge that reads in millimeters. Trying to read to the nearest 1/32 of an inch can get confusing to some people and many modern cars specify toe in angles and millimeters anyway. The photos below use the ART "dreamstick" toe gauge (not the same company as above) because it is more stable and easy to read than a ruler and thus produces more repeatable measurements. (My price was $85, a steel ruler will cost much less but will probably annoy you more.) lots of solid concrete blocks (not cinder blocks) There are two uses for the blocks. First, you want to put weight equal to the driver's weight on the driver's seat while aligning the car. Blocks are convenient, cheap ($0.98 at Lowe's), and at 35 lbs. each you probably only need 4 to 8 of them. Second, I put blocks under each tire to raise the car off the ground and let me adjust parts without jacking and lowering the car. For the toe adjustment, you will crawl under the car and find the midpoint, so make sure your platforms are tall enough to allow you to fit underneath. Either that or make friends with a small and reliable person. I used a single layer of 2 blocks to make a nice wide platform for each tire, with plenty of room for chocks. (My price was $20 for all blocks.) Do not get cinder blocks, which have hollow spaces in them. These blocks could collapse with you under the car! Get only solid slabs of concrete. Mine were 14"x6"x4" or so. If you are a hefty person, you might need thicker platforms to get under the car -- you are on your own for that. Do your research and preserve your life! Blocks used for platforms and driver ballast. Click this or any following picture for larger image. Image hosting courtesy of Photodump.com Floor tiles (or very thin, very smooth plywood "tiles") and some automotive grease Most garages are not particularly level; the tiles will shim each tire until the car is level. Each tire will have at least two tiles so we can create turn plates with a little automotive grease. This lowers the friction enough that we don't have to jump on the car or roll it forward and back to reset the suspension with every little change. (I already had tiles. They are less than $0.50 per tile at Lowe's. I used less than 20 tiles for slip plates plus shimming.) Two bars aluminum conduit, four jack stands, string, measuring tape, plumb bob, chalk line, pencil This will create a set of reference lines, to which we will adjust the toe of each wheel. (Conduit is a few dollars for 8', jack stands $20 a pair, measuring tape $3, plumb bob $7, chalk line $5, so guess $60 total if you need to buy it all. I had most of it already.) You don't need conduit, you just need poles of some kind, and they don't need to be perfectly straight; they just need to be longer than the car is wide. You can also improvise the jack stands; all you need is a sturdy, adjustable way to set the height of the poles and pull the string tight. Notebook and pen! Write down every little thing you do. After you are done, transcribe the notes into a useful, more compact set you will keep. As you go, especially your first time, write down everything because you won't know what will be useful later. You might get confused and have to backtrack. (A spreadsheet would be very useful here, both as a record storehouse and for caster calculations, but you might get the keyboard very dirty! I just use paper.) All of this takes very little space in the garage when you are not using it. If you want to dispense with the concrete blocks, that's fine, you just have to do something else to simulate the driver's weight, and you must have some way to crawl under the car without jacking it up -- platforms of wood or metal or just a pit under the car. My total above is about $425. This is much more than the cost of several alignments at the dealer, but you will be able to align your car anytime you like from now on. I will show that you can do it much better than the dealer is likely to as well. Some people might complain that these materials seem too improvised to do a good job. I assure you this isn't true. If you go to enough races and look into enough pits, you will see many of the pros doing the same things -- including several champions. Procedure The first thing to do is plan, plan, and plan. Allow enough time for you to finish. Get a blanket or two to protect the drivers seat from the weight that will be on it. Protect your steering wheel also; I scratched mine with a concrete block. Have the tools needed to adjust the relevant parts on your car. Have a list of your target values for the suspension angles. Assemble the special tools and equipment listed above. Some people align the car with a half tank of gas. This makes no sense to me unless you are racing until the tank empties; in that case, half a tank is the average weight of the gas in your car. I always autocross or run track days with a full tank to avoid slosh and fuel starvation. I get more gas when I hit half a tank. As a result, I did my alignment with a nearly full tank of gas. Make gas weight considerations part of your planning. Here is the order of operations: initial set up set ride height corner-weight balance adjust caster adjust camber adjust toe adjust bump-steer recheck caster, camber, toe, and readjust if necessary The items in gray will not be discussed in Suspension 401. They are reserved for a future and more advanced course. Initial Set Up Park your car where you will be able to work. Select a surface that is as smooth and level as possible, without cracks or seams. Chock the rear tires/set parking brake and jack up the front end. Put your platforms (described above) under the front wheels but don't lower the car yet. Put two tiles on top of each platform such that the smooth faces of the tiles are touching each other. These will be our slip plates, but don't put grease between the faces yet. Use a long straight edge (like your brand new conduit, or a straight board) and your camber gauge to see if the two platforms are level with each other. If not, add tiles to the low side under the slip tiles until the two sides are level. Now put a generous amount of grease between the top two tiles, as evenly as possible. (The grease will be spread flat from the weight of the car, but might have distorted our leveling attempts had we used the grease earlier.) Platform and shims under driver's front tire. Board used for leveling... ...via a simple carpenter's level, or better yet... ...via the digital camber gauge on its side. Test fit your camber gauge to the wheels, rotating the wheels if necessary to ensure that the balancing weights will not interfere. Lower the car. Notice how the tires push the top tile outboard an inch or two. This was the main purpose of the slip plates: to allow this motion. The other purpose comes when measuring caster. Slip plate under driver's rear tire after lowering car. The top tile has slid 1.5 inches outward. If you forget the slip plates and leave the car for a week, the outward forces can ruin a floor! Cement will be fine (and who would care if it wasn't), tile will be wrecked, and an epoxy paint surface will probably be marred. Chock the front tires, then repeat for the shim procedure for the rear tires. You need slip plates in the back also, so don't forget them. Chock, lift, build platforms, slip tiles, level the platforms left and right, grease the slip tiles, lower the car. I left chocks and/or 2x4s in front and in back as I worked as a nice precaution against forgetfullness. If you forget the chocks you might learn how a very slight incline can still spell disaster. (Do not bother leveling the platforms front and back though. If the car is not level front and back, you will never notice it. Exception if you are corner-weight balancing, which we are not doing today. Even then you will probably not notice it and can thus skip it. This advice from Carroll Smith's first book, Prepare to Win.) In your notebook, record how many tiles you used and where you used them. If you plan to do this often, you might mark the floor to show where you put the platforms. Find a collection of stuff, like our extra concrete blocks, equal to your body weight and put it in the driver's seat and footwell. Protect your upolstery with a heavy blanket or two first! Ride Height Measurement and Adjustment Not covered in this course. (However, if you have just installed or about to install new parts, now is a good time to measure ride height, camber, caster toe, before making any adjustments at all. Both ride height and camber will change a great deal in the first few weeks, with slower changes thereafter. This is a good time to look for left-right asymmetry and possible causes.) Corner-Weight Balance Measurement and Adjustment Not covered in this course. Caster Measurement and Adjustment This measurement is the trickiest one, so work as carefully as you can. To measure caster, you turn each wheel left 20 degrees and measure the camber angle, then right 20 degrees and measure the camber angle. The difference in camber angle is related to the caster angle we want to measure by a simple "caster conversion factor" of 1.5. So without getting into the trigonometry, suffice it to say that if your camber angles were found to be +3.2 degrees and -1.5 degrees, then the caster would be [ 3.2 - (-1.5) ] x 1.5 = 7.05 I have kept all the digits of the result, but be aware that your precision is really not that fine because you measured the component angles only to the nearest 0.1 degree. If the gauge reads 3.2, the angle might be anywhere from 3.150 to 3.249. The standard deviation on the measurement is actually [camber accuracy] * [caster converstion factor] * sqrt(2) / sqrt(12) = 0.1 * 1.5 * sqrt(2) / sqrt(12) = 0.0612 degrees No matter what caster angle you find, the standard deviation is always the same size. If you don't know where the above numbers came from, don't despair, the little trick taught in junior high school chemistry classes ("keep track of your significant figures") works pretty well and in this case provides a 90% confidence range instead of the standard deviation. In our example, using the standard deviation, caster = 7.05 +/- 0.06 degrees The moral of the story is, don't bother getting the caster painstakingly accurate to the second decimal place because your gauge can't measure the angle to that precision anyway. (There is a trick to get 5x more precision out of your gauge, which I will share in a later document...after I test it.) The improvised slip plates under the wheels will allow them to turn with very low friction. Unlike commercial plates, the angles are not conveniently marked on the tiles. A clever person might make the top tile smaller, and mark angles on the second tile, but the grease and the slip of the tile when the car is first lowered might foil that cleverness. I tried it, with terrible results, so I recommend an alternate method to find the turning angle. (I should mention that I tried 3 different "clever" methods, with lousy real-world results, before using the following method, which is what the manufacturer of my gauge recommended in the first place. I'm just describing it much better than they did.) The easiest, and I think the most repeatable method of finding 20 degrees is to get a straight-edged sheet of cardboard and mark 20 degree lines on it, relative to the straight edge. Make your lines big! Center your steering wheel. Place a straight, square sheet of plywood on the ground and lean it against the wheel face so it is exactly flat against the wheel face. (You need to create a flat surface if your wheel face is not flat; see "bridge" below.) The bottom edge of the plywood is exactly parallel to the top edge, which is parallel to the face of the wheel because they are in direct contact. Lay the cardboard sheet flat on the ground and push it up against the bottom of the plywood. Now your cardboard sheet is parallel to the wheel face, and marked for +/- 20 degrees. Tape the carboard sheet to the ground now. Next, put the plywood on one of the 20 degree lines and lean the plywood toward the tire. Have a friend turn the steering wheel until the plywood can lie flat against the face of the wheel. That is 20 degrees of wheel turn. You absolutely need a friend to help with this because the slip plates allow the steering wheel to turn back to center unless somebody is holding it. 20-degree lines barely visible on cardboard, wheel spanned with improvised bridge, plywood sheet on 20-deg line and bridge. Note that the wheel needs to turn a little more to the right for the bridge to line up with the plywood. Measure the camber for 20 degrees left and 20 degrees right. Make sure that the gauge pegs are firmly on the wheel's rim, with no air gap. If the wheel were a clock, you would want the top of the gauge pointing straight up toward 12 and the bottom straight down at 6. Compute the caster angle resulting from your measurements. Adjust caster and repeat until you have the desired setting. Then do the other tire. Record your angles and changes as you go! It is important to match left and right caster or the car will pull to the side when driving. (Often, uneven caster is deliberately introduced to counteract the crown of the road, which tends to push a car to the right. I personally would not put this compensating "cross-caster" into a performance car, but might do so for most other cars. "Cross-camber" is another option I elect not to use; it has a similar effect.) Driving feel of the car is sensitive to left-right asymmetry, so spend your energy getting a good match between left and right. Write down the starting caster and the changes you make for each new mesurement. As you iterate measurement and adjustment, your partner on the steering wheel will learn the +/- 20 degree range and you won't need the plywood and cardboard. It is not necessary to tighten the locknuts on the caster adjustment parts with each iteration either. As a result, the caster adjustment can go fairly quickly. An early attempt at caster adjustment (ignore the string...failed technique) showing measurement of camber at 20 degrees left. One pitfall if you have aftermarket parts is "Heim joint backlash". Many aftermarket parts have a racing-grade rod end with a spherical bearing -- the Heim joint. The rod length is adjusted by rotating a turnbuckle around the threaded rod. The problem is that rotating the turnbuckle often rotates the spherical bearing also, until the bearing reaches the extreme end of its rotation range. If you are turning the bearing, you are not changing the length of the suspension part. So you need to account for this in your calculations (difficult) or remove the backlash at the end of each adjustment (easy, and recommended). For instance, if you are going to shorten the suspension part by 3/6 of a full turn, you would use your wrench to turn the turnbuckle (or adjustment nut, or whatever) until the spherical bearing turns all the way to its stopping point. Then start counting your rotation of the adjustor to your 3/6 value, then back up the turnbuckle until the spherical bearing is once again centered within its rotation range. Do this every time you adjust a Heim joint! Why don't I simply the fraction of a turn to 1/2? Because usually you will only have room to turn the wrench 60 degrees or so anyway, so I prefer to count each wrenching operation. If you use this notation, you will never confuse yourself if "a turn" meant 60 degrees or really meant 360 degrees of rotation -- just write 1/6 turn vs 6/6 turn. In some of my notes I have 0.5/6 turn. It is a good policy that pays off the next time you align. Another pitfall: many wheels do not have a nice flat face. You need to be sure you are truly flat against the face for the turn-angle measurement to work, so either get your plywood sheet so it touches a flat surface or you have to rig a flat surface on the wheel by running a strip of wood as a bridge horizontally from the rim on one side, over the centercap, to the rim on the other side. Take your time, try to be repeatable. If your notes are showing inconsistencies in how much adjustment yields how much angular change, sloppiness in the estimate of 20 degrees of turn is probably the cause. It is possible to get it very very exact and repeatable if you try! Keep all the tools and templates you make (and mark them so they won't get used for scraps) so you can use them next time. And finally: Make notes on the direction of rotations and how it affects the caster angle. Do the same for the lock nuts, if any. I use one of the "right hand rules" from physics, plus a little drawing. Whatever you use, take good notes and you will thank yourself later. I warned you this was the trickiest measurement, but if you have your tools ready it won't be that bad. Also, you only do the front tires instead of all four tires like you will for the following measurements. When you finish with caster, make sure the steering wheel is perfectly centered. Remove your keys from the ignition or you risk forgetting them and draining your battery as a result. Camber Measurement and Adjustment By comparison to the other angles, camber is a piece of cake. Just ensure your steering wheel is in the middle and use your gauge on all 4 wheels. As before, take care to have the gauge straight at 12 o'clock and 6 o'clock on the wheels, firmly pressed against the rim. Record your angles and the changes you make to reset them. Remeber to counter the Heim joint backlash, if it applies to your parts. (This was almost too easy, huh?) If you have the fancy, easily-adjustible camber parts, you will want to set an aggressive camber on track days and you will want a more reasonable camber for the rest of the time. Careful notations here will be very important and save you much time later. For a street car, I recommend you set the street camber now, then do the toe, then test your aggressive camber setting after you have finished with the street alignment. Toe Measurement and Adjustment It is now time to create reference lines that are parallel to the true centerline of the car. We didn't do this during the initial set up because the strings can really get in the way of the caster measurement. First, find the midpoint of the front end of the car by measuring between the lower control arms (LCAs). If there is a convenient way to hang a plumb bob between the front wheels, use a tape measure to find the center and mark it. Then use the plumb bob to mark the garage floor. Do the same for the rear of the car. Note: if you jack up the car, the slip plates might allow the car to end up in a different position. That is, the car probably won't come straight down, so find these midpoints without jacking up the car at all. The tire platforms must be tall enough for you (or a smaller friend) to fit underneath the car, or you will never get a good midpoint marked. An early attempt at finding the midpoint, using gap tool as improvised plum bob. After lifting and lowering, sure enough, the car didn't come straight down! If there are no handy spots in the middle from which to hang the plumb bob, just use the bob to make two marks on the floor, one directly beneath each LCA pivot, then find the middle of the two marks. It is crucial to select the same spots on the left and right. For instance, I selected the most inboard part of the LCA pivot point, and hung the plumb bob in exactly the same way for both sides. Remember we will measure toe to the millimeter, so get this as precise as possible! Choose a spot you can reproduce on the other side without question. I ended up mistrusting my chassis midpoint, so I used the LCA technique, which is more accurate I think. Once you have the floor marked with front and rear midpoints, stretch the chalk line under the car and snap it. (If you have no partner to help you, just use the weight of a jack stand to hold one end of the line securely against the floor while you snap the other side, then switch.) This creates your midpoint reference line. Set up two jack stands to hold a conduit bar parallel to the bumper at the front of the car, then likewise for the rear. Tie strings between the conduit bars so the strings travel along the sides of the car a few inches from each tire. Adjust jack stand height so the string height is right in the middle of the center caps of the wheels. Pull the strings tight by moving the jack stands further apart as you get the distances even. Right at the conduit, carefully measure distances from the chalk line to the strings and get all 4 distances exactly equal (just shove the strings along the conduit to the left or right). I used 38" as my distance. Perform a double-check by measuring from each wheel hub (or center cap, or some other reference) to the string. If the distance is different from left wheel to right wheel, then either you have major frame damage or (most likely) you screwed up the centerline. If this happens then just rub out the chalk line, crawl under the car again, and remake the centerline. Some cars have a different track width in front vs. the rear, so only worry if the distances are far off front to back as long as it is very close left to right. If you have a friend helping, it might be smart to perform a triple-check by carrying the rear rod, with strings attached, over the car to the front rod. Then make sure the strings are tied exactly the same distance apart at both ends by comparing them right next to each other. That will ensure the greatest precision in your toe settings, but it won't work if the conduit isn't perfectly straight. Return the rear rod to the back and center it again relative to the reference line, but without pushing the strings around this time, only by moving the rod left and right. Check those hub distances again. Before doing further work on the toe, wipe up the chalk! Leave a little bit of the chalk line right by each conduit, where you need it, but remove the rest. Otherwise you end up wiping it up with your clothes when you slide under the car. Start measuring toe at each wheel. Use your tool to measure the distance between wheel and string at two points: the frontmost part of the rim and the rearmost part of the rim. The difference in millimeters is the amount of toe for that wheel. There is no need to convert to an angle. (When you select your target value, you must convert from angle to mm offset for a rim of your size, but you never need to convert back the other way. In my case, my service manual provides mm offset for my rim size directly.) For a rear-wheel drive car, you will want anything from 0-3mm toe IN for the front of the car and 0.5-5mm toe IN for the rear of the car. The more powerful your engine, the more toe IN you are likely to want for the rear. (On a powerful rear-wheel drive car, never, ever use toe OUT in the rear! Don't even get too close to zero.) Adjust, and take care to get the readings the same on both sides of the car. Thanks to our slip plates, there is no need to roll the car back and forth or jump on it, etc. Toe is measured relative to the string, which is parallel to the centerline of the car. A note on measuring toe with strings: there is no need to guess where the center of the string lies on the ruler. We are taking the difference between two measurements so just use the edge of the string and you will be more accurate. If you are very careful, you can estimate fractions of a millimeter to the nearest 0.2 or so, and I recommend that you try. (That is another chemistry trick.) Bump-Steer Measurement and Adjustment Not covered in this course. Repeat Each angle has the potential to interact with the others when adjusted, so go back and see how much your first adjustments drifted by the end of the procedure. Correct as necessary. If you plan to run a more aggressive camber on track days, now is the time to set the camber that way and make sure nothing funny happens to caster and toe. Congratulations! Your alignment is complete! Go make sure that all lock nuts are in place and tight, that all lock collars are tight, and that you haven't left any tools under the car. Pull the weight out of the drivers seat, put the car back on the ground, and clean up. Save your slip plates, bridge, the 20-degree template, and the plywood rectangle. Put the conduits someplace where they won't get bent. Relax a bit, but then make sure to transcribe your notes for next time. Case Study Here are the factory specs for my car, a 1993 Nissan 300ZX Twin Turbo: Front Camber -1.6 to -0.1 deg Front Caster 8.9 to 10.4 deg Front Toe 0.0 to 0.09 deg Rear Camber -1.6 to -0.6 deg Rear Toe 0.01 to 0.20 deg (A Totally Unfair) Comparison: compare this to the before and after alignment of my car, as performed by the dealer in Sep. 2001. Before After L R L R Front Camber -1.8 -1.5 -1.8 -1.6 deg (out of spec before and after) Front Caster not meas not meas Front Toe (deg) 0.13 0.01 0.05 0.08 deg (barely in spec after) Front Toe (mm) 1.84 0.14 0.71 1.13 mm (barely in spec after) Rear Camber -2.1 -1.3 -1.7 -1.4 Rear Toe (deg) 0.40 0.16 0.20 0.17 deg (barely in spec after) Rear Toe (mm) 5.67 2.27 2.84 2.41 mm (barely in spec after) (Note: The dealer measured toe in degrees to the nearest 0.01. The conversion to mm with a 16" wheel rim gives a raw precision of +/- 0.14 mm...about the same as you can do by eye. The camber measurement is no more precise than we can do either. The is caster is slightly more precise, but with a little trick you can match the laser equipment precision.) It is unfair to indict the dealership because this alignment was done with stock parts, which do not provide much adjustment range (none at all for caster). Camber can be slightly adjusted in back, but not the front. Attempts to loosen the bolts, forcefully shove the parts, then retighten the bolts account for the slight camber change in the front. My springs were the originals, about 8 years old at the time. They would get another 4 years of use before being replaced in 2005. The technician made the front camber worse on the RF wheel to minimize the "cross-camber", just so you know...the LF wheel was already at the limit of adjustment. I wanted to go back into the shop area with the technician during the work, sitting in the driver's seat in fact, but I was refused. I told the tech I track my car and wanted the best alignment he could provide. The tech declined to try to improve the alignment job after I saw the results. When I complained that I thought this was $120 poorly spent, the tech said that if I wanted it better I should buy some alignment tools and just do it myself in my garage. I thought he was being some kind of smart guy at the time, but eventually this is just what I did. Here is my new alignment, performed by me personally in Apr 2005. I do not know the "Before" values because I installed my new parts in winter, months before I ordered the alignments tools for spring. I'm sure the camber values were awful. After L R Front Camber -0.1 -0.1 deg Front Caster -8.55 -8.55 deg (happened to match exactly) Front Toe 1.0 mm 1.0 mm Rear Camber -0.2 -0.2 deg Rear Toe 1.0 mm 1.0 mm Ride Height 26 1/2 to 26 7/8" all around I have deliberately not provided asymmetry to compensate for road crown. My choice of camber is far too close to zero for maximum cornering grip, but I set it that way to maximize tire life and because I have new springs. After years of extreme camber, my tires are very worn on the inside edges and pristine on the outside. My tires can't be rotated, so this is the next best thing to new tires for now. Also, I expect my springs to settle over the coming months and provide more camber as the ride height decreases. (The new springs were supposed to lower ride height by 0.8" or so, but when first installed they put the car to above stock specs.) Finally, the purpose of the fancy adjustable camber arms is to dial in more negative camber for track days and then take it back out afterward. I no longer need to compromise between tire life and track performance. Now that I do my own alignments, I can make corrections as needed. I deliberately chose a caster angle slightly smaller than spec. In my opinion, the road feel and high speed stability on the car are significantly more than required, but the turning responsiveness could use some help. This is my first bit of tinkering with caster. (I'll discuss how to find optimal final alignment targets in the 201 and 202 courses if and when I get around to writing them.) As a follow-up, here are the stats in July 2005: Before After L R L R Front Camber -0.3 -0.4 -1.5 -1.5 deg Front Caster -8.55 -8.15 deg -8.55 -8.55 deg Front Toe 0.5 mm 0.5 mm 0.5 mm 0.5 mm F Ride Height 25.8 in 25.7 in (not adjustable) Rear Camber -0.5 -0.4 deg -1.0 -1.0 deg Rear Toe 1.0 mm 1.0 mm 1.0 mm 1.0 mm R Ride Height 25.8 in 26.6 in (not adjustable) I found it odd that the rear right spring had not sagged over the months. But that's the way it was. The camber angles had indeed changed over time, but not as much as I expected. My new angles were my final street targets. The front toe drifted toward zero and I left it there. Retrospective Overall, my first attempt at alignment took several weekends because of all the false starts. I lost a week just waiting for the longer pegs for the camber gauge to come in. Measuring +/- 20 degrees with 3 different techniques took a day and a half, and in the end I went back to the method described by the camber gauge manufacturer. I hope this write-up will save everyone some time. The guy at the dealership with the fancy equipment took 27 minutes to do his 2-angle alignment. I hope to become similarly fast, with similar precision, but with full control over the results! The July 2005 alignment took half an hour for caster, so that is already a big improvement. I have demonstrated that you get very good precision doing this stuff in your garage. The more important point is that you can now afford to do this very frequently and keep your car in alignment. In this way, averaged over time, you are guaranteed to have a better alignment doing it yourself than if you paid somebody else to do it less frequently. Because the camber suffers the most change as springs sag over time, you can keep your alignment in good shape for quite a while by checking and adjusting the camber (the easy one!) alone. Dr. John Krane, Physicist at Large This document is copyright © John Krane 2005. Please feel free to link to this article or use it for any non-profit and non-commercial goal if you abide by the following conditions. I require you to keep this document in its entirety, including leaving my name, all my pictures, and this notice. I grant permission for people to add pictures specific to their cars if they wish, with descriptive captioning, but they must leave my pictures, captions, and all text intact and in place. Finally, do not read my stuff, reword it slightly, and then try to pass it off as your own! (Notice the credit I gave to Carroll Smith and photodump.com. Credit me if you refer to me!) Feel free to contact me with questions at jkrane_AT_netzero_DOT_com . Happy aligning! Go to Krane's Automotive University, suspension major Go to Krane's Home Page - John
Follow Ups	Do-it-yourself alignment (Suspension 401) - Technomancer 12:28:07 08/31/05 VTF! Nice writeup. (n/m) - just4kinks 13:51:13 08/31/05 2nd. VTF!!! - 91z tt 14:28:46 08/31/05 good God, that's awesome (n/m) - apudapus 15:42:09 08/31/05 Very well done! Thank you. (n/m) - Zirvana 17:11:57 08/31/05 awesome...thanks!! (n/m) - turbo300 (miami) 18:48:40 08/31/05 Very thorough. - doug8867 22:00:42 08/31/05 Yes, I knew that. - Technomancer 04:59:30 09/01/05 Works as long as tires don't have a specified inside/outside (n/m) - Zirvana 08:31:23 09/01/05 Good point. My new tires are like that. - Technomancer 09:28:33 09/01/05 I tried to do that switch recently once again on my 94TT. - Zirvana 10:01:57 09/01/05 good job man! (n/m) - maxboost83(WA) 04:15:11 09/01/05 Give me a good stock tip. (n/m) - longhornz32(Dallas) 10:03:41 09/01/05 Ever hear of ETFs? - Technomancer 10:19:05 09/01/05 I've been hearing a lot about ETFs. I'm currently - longhornz32(Dallas) 14:42:33 09/04/05 Wow great question! - Technomancer 10:19:52 09/07/05 What is the meaning of life? (n/m) - dpjax 13:11:03 09/07/05 42 - Technomancer 14:34:54 09/07/05 thank you very much for that. Great read. - BCs300z 18:18:08 09/01/05
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