DIY: Wheel Alignment.
04-07-2012, 09:13 PM
#1
DIY: Wheel Alignment.
With The Texas 8 rapidly approaching I decided to do my own alignment, here is how you do it(revised edition).
Go to this website and read a lot:
http://www.miata.net/garage/alignment/index.html
Drive your car onto a completely level surface. (or use math to offset your camber angles.)
Calculate how far off your toe settings are and front are using a string box.
Use a plumb bob and math, or a camber gauge figure out your camber.
Adjust the rear wheels first. Turning both adjustments in the same direction adjusts camber. Turning them in opposing directions adjusts toe. You can use measurements to make educated guesses, or you can use trial and error.
On the front wheels adjust to max castor, then max camber, and figure out which you need to back off on to get the settings you want. Since the camber and castor adjusts effect each other this gets you closest to max castor when you are done.
Last thing adjust toe. Forgot to mention initially, you can do this on the ground as well. Try to get it right where you want it.
Drive around the block then repeat the process until everything is perfect.
Drink a beer, you deserve it.
Go to this website and read a lot:
http://www.miata.net/garage/alignment/index.html
Drive your car onto a completely level surface. (or use math to offset your camber angles.)
Calculate how far off your toe settings are and front are using a string box.
Use a plumb bob and math, or a camber gauge figure out your camber.
Adjust the rear wheels first. Turning both adjustments in the same direction adjusts camber. Turning them in opposing directions adjusts toe. You can use measurements to make educated guesses, or you can use trial and error.
On the front wheels adjust to max castor, then max camber, and figure out which you need to back off on to get the settings you want. Since the camber and castor adjusts effect each other this gets you closest to max castor when you are done.
Last thing adjust toe. Forgot to mention initially, you can do this on the ground as well. Try to get it right where you want it.
Drive around the block then repeat the process until everything is perfect.
Drink a beer, you deserve it.
Last edited by Harlan; 04-08-2012 at 09:14 PM. Reason: Original only made sense to me.
04-07-2012, 10:20 PM
#3
Voids warranties
Nice write up. You certainly did a lot of work. However your thought process and logic are flawed. I will explain. You will get defensive but that's ok because people need to know.
You NEED to do an alignment on a flat level surface. No if ands or buts about it. You may be able to make up the difference mathematically, but that doesn't make up for the weight transfer that happens in the chassis from being uneven. Even in just the 1 deg camber change in your driveway surface. If you were to put corner weight scales under you would be surprised how much that 1 deg makes. You did your alignment with a slight preload to the passenger side springs. Your alignment will never be right.
Taking measurements with tape measures and hanging strings with your naked eye is barbaric at best. Its the stuff farm tractors and lawn mowers are made of.
Aside from all that lets look at the value of your time...
I figure you spent a least a couple hours at this if not more. Between measuring, adjusting, test driving. Remeasuring, readjusting, and retest driving, countless times. I assume you spent...Lets say 2 hours.
A good alignment form a reputable shop should cost you about a hundred bucks and take about a half hour, Barring any stuck adjusters.
Very simple math tells us you spent $400 worth of your time on a somewhat kinda close to spec, crooked alignment.
Your own attention to detail is worth more than that and your car deserves better.
You NEED to do an alignment on a flat level surface. No if ands or buts about it. You may be able to make up the difference mathematically, but that doesn't make up for the weight transfer that happens in the chassis from being uneven. Even in just the 1 deg camber change in your driveway surface. If you were to put corner weight scales under you would be surprised how much that 1 deg makes. You did your alignment with a slight preload to the passenger side springs. Your alignment will never be right.
Taking measurements with tape measures and hanging strings with your naked eye is barbaric at best. Its the stuff farm tractors and lawn mowers are made of.
Aside from all that lets look at the value of your time...
I figure you spent a least a couple hours at this if not more. Between measuring, adjusting, test driving. Remeasuring, readjusting, and retest driving, countless times. I assume you spent...Lets say 2 hours.
A good alignment form a reputable shop should cost you about a hundred bucks and take about a half hour, Barring any stuck adjusters.
Very simple math tells us you spent $400 worth of your time on a somewhat kinda close to spec, crooked alignment.
Your own attention to detail is worth more than that and your car deserves better.
04-07-2012, 10:29 PM
#4
1 deg difference is huge and must be accounted for, but once it is, the difference between a level surface and a slightly sloped one is much less than weight distribution of passengers, suspension slop, or just having a full vs empty tank of gas. I'm not saying you're wrong, just that I was more worried about getting it driving in a straight predictable line with decent handling. If my driveway had a worse slope it would start to matter, but how much weight does 1deg really shift? Not enough for me to lose sleep over. Cheat sheet incoming, if excel will play.
04-08-2012, 08:43 AM
#9
In the amount of time it took me to read that, I leveled my garage with tiles and placed my car on scales. In the amount of time it would take me to read it again so I'm sure of what I'm supposed to do, I aligned the car and corner balanced it using toe plates and a camber/caster gauge.
Use the right tool for the job, its easier, faster, more accurate and you don't need to worry if you carried the 1 or placed the decimal point in the correct place.
Use the right tool for the job, its easier, faster, more accurate and you don't need to worry if you carried the 1 or placed the decimal point in the correct place.
04-08-2012, 09:01 PM
#10
Found this link and it's pretty helpful. Includes using a straight edge to eyeball alignment for a quick check. Also the suspension is pretty similar including moving the rear adjustments together for camber and opposed for toe.
http://www.miata.net/garage/alignment/index.html
I may have been off on my initial alignment if the front and rear axels are different lengths, didn't occur to me when I did it. But either way I'm much closer than I was before and now I have a reason to devote another afternoon to drinking beer and working on the car.
Team, you are absolutely right. Getting a good camber measurement took several minutes per tire and was a pain in the butt. Gonna put one on my wish list.
Aligning a car is like measuring with a micrometer, marking with chalk, and cutting with an axe. At least at home you can take as much time as you want to get the result you want.
http://www.miata.net/garage/alignment/index.html
I may have been off on my initial alignment if the front and rear axels are different lengths, didn't occur to me when I did it. But either way I'm much closer than I was before and now I have a reason to devote another afternoon to drinking beer and working on the car.
Team, you are absolutely right. Getting a good camber measurement took several minutes per tire and was a pain in the butt. Gonna put one on my wish list.
Aligning a car is like measuring with a micrometer, marking with chalk, and cutting with an axe. At least at home you can take as much time as you want to get the result you want.
04-08-2012, 10:09 PM
#11
Voids warranties
04-08-2012, 11:05 PM
#12
in my experience small changes/deviations don't mean much WRT performance. My alignment corner balance guy loves me because I don't make him waste time splitting hairs over tenths of a degree or a couple of pounds. Pull your car off and put it back on and it will read more than that difference. The uninformed person is usually the most ****, just sayin' ...
04-28-2012, 09:25 PM
#13
Two important additions!! The alignment bolts need a lot of torque to hold up to rough driving. The miata guys use up to 150ft/lbs plus. I don't know what a good number for the 8 is, maybe someone else can chime in. Also if your alignment ends up shifting badly, either take the time to redo it right or you will be the one buying tires in the middle of the Texas 8. Learn from my mistake.
05-04-2012, 07:18 AM
#14
There is so much wrong with the first post.....so I will try to just hit the high points:
1. Your car must be level. This is of the utmost importance.
2. Your string box needs to be set up so your strings are parallel. Having the string equidistance to the hubs isn’t going to achieve that. You MUST set up a string box first using conduit to find your hubs delta distance between front and rear. You CANNOT use front to rear track measurement you find in magazines because that is measured at the tires intersection to ground (takes camber into account). I know this because I measured and know the values.
3. I understand that all you had laying around is a tape measure, but this is not good enough for toe measurements. If you can’t afford a $30 digital (or analog) caliper with depth gage, then use a long bolt with a nut on it. I use both of these methods with good results. I use a M8 bolt with 1.0 mm pitch (thread to thread is 1 mm) and I place the bolt against the wheel lip (helps to sand the end of the bolt to prevent scratches) and I spin the nut up to the string. Then I move the bolt to the other side of the wheel lip and count the threads. I do this until I have it correct, then I double check with my digital caliper. Either you will want toe equal from front lip to back lip or you will want a 1 mm difference. More and you will eat tires quickly. Remember, these measurements are taken at the wheel lip (18” diameter) and not at the tire diameter (25.9”), so if you have a 1 mm delta from front to rear, that is not 1 mm of toe. Calculate everything to angles, it takes the subjectivity of toe measurements out of the equation.
4. You also must use turn plates or something slippery for your tires to unload properly after adjustments. I use large zip lock bags with some oil in them…works great.
5. Rolling the car between adjustments also helps check that you have unloaded the suspension. This is possible with a string box placed on the car. Because I didn’t want to spend a lot of money in tools for this job, buying Smart Strings was out of the question. Instead I bought $2 suction cups from Harbor Freight and modified them so a 6” bolt stuck out of the housing. I then place these on my fenders, in line with the wheel hub. I use fishing line with loops tied at the ends and place it over the threaded bolt. The threads allow for accurate adjustment for string placement. Measure and obtain the CORRECT delta from front hub to string as rear hub to string. You will obtain this correct delta measurement when setting up your original string box with conduit. I would share my results of this delta, but this is easy to obtain. If you are unable to obtain this delta, you shouldn’t try to perform your own alignment.
I didn’t mean for this post to turn into a bash, I guess I was just a little sensitive about a DIY alignment on RX8Club as I was thinking about creating one. After seeing this I just may have to......
1. Your car must be level. This is of the utmost importance.
2. Your string box needs to be set up so your strings are parallel. Having the string equidistance to the hubs isn’t going to achieve that. You MUST set up a string box first using conduit to find your hubs delta distance between front and rear. You CANNOT use front to rear track measurement you find in magazines because that is measured at the tires intersection to ground (takes camber into account). I know this because I measured and know the values.
3. I understand that all you had laying around is a tape measure, but this is not good enough for toe measurements. If you can’t afford a $30 digital (or analog) caliper with depth gage, then use a long bolt with a nut on it. I use both of these methods with good results. I use a M8 bolt with 1.0 mm pitch (thread to thread is 1 mm) and I place the bolt against the wheel lip (helps to sand the end of the bolt to prevent scratches) and I spin the nut up to the string. Then I move the bolt to the other side of the wheel lip and count the threads. I do this until I have it correct, then I double check with my digital caliper. Either you will want toe equal from front lip to back lip or you will want a 1 mm difference. More and you will eat tires quickly. Remember, these measurements are taken at the wheel lip (18” diameter) and not at the tire diameter (25.9”), so if you have a 1 mm delta from front to rear, that is not 1 mm of toe. Calculate everything to angles, it takes the subjectivity of toe measurements out of the equation.
4. You also must use turn plates or something slippery for your tires to unload properly after adjustments. I use large zip lock bags with some oil in them…works great.
5. Rolling the car between adjustments also helps check that you have unloaded the suspension. This is possible with a string box placed on the car. Because I didn’t want to spend a lot of money in tools for this job, buying Smart Strings was out of the question. Instead I bought $2 suction cups from Harbor Freight and modified them so a 6” bolt stuck out of the housing. I then place these on my fenders, in line with the wheel hub. I use fishing line with loops tied at the ends and place it over the threaded bolt. The threads allow for accurate adjustment for string placement. Measure and obtain the CORRECT delta from front hub to string as rear hub to string. You will obtain this correct delta measurement when setting up your original string box with conduit. I would share my results of this delta, but this is easy to obtain. If you are unable to obtain this delta, you shouldn’t try to perform your own alignment.
I didn’t mean for this post to turn into a bash, I guess I was just a little sensitive about a DIY alignment on RX8Club as I was thinking about creating one. After seeing this I just may have to......
Last edited by JCrane82; 05-04-2012 at 08:35 AM. Reason: typos
05-04-2012, 12:09 PM
#18
99% of people are like you, but for me I buy the tools and do it myself for several reasons. 1- I can check and adjust at the track, 2- I make adjustments all the time that require corner balancing (i have scales) and subsequently I need to check.and adjust my alignment., 3- even though I may never save enough to pay for my tools, my tools have a high resale value, Usually 60-75% or more if I buy second hand.
05-04-2012, 12:12 PM
#19
99% of people are like you, but for me I buy the tools and do it myself for several reasons. 1- I can check and adjust at the track, 2- I make adjustments all the time that require corner balancing (i have scales) and subsequently I need to check.and adjust my alignment., 3- even though I may never save enough to pay for my tools, my tools have a high resale value, Usually 60-75% or more if I buy second hand.
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