Advice requested from those of you who have successfully checked camber at home

Practical advice (helpful hints & suggestions) requested from those of you who have successfully checked camber at home (to sufficient accuracy).
If you have never checked your automotive alignment camber at home, you probably won't be able to add much practical value to this thread; however if you have actually measured your wheel camber with sufficient accuracy at home, you almost certainly can add valuable pragmatic hints to this thread (such that we'll all learn from your experience).
I am researching whether automotive alignment camber quick checks are yet possible to a reasonable degree of accuracy using a free app on a common mobile device (either iOS or Android, both of which I own).
A search does find a variety of methods to check camber at home: https://www.google.com/search?q=check+camber+at+home where some of those articles used mobile phone apps (e.g., XXXXXX)
Here I am just asking for advice from those of you who have successfully checked your camber at home using your smartphone to measure the angles to sufficient accuracy.
To find apps which measure angles to sufficient accuracy, I have already run a variety of Google searches of the general form: 1. review best ios free app angle automotive alignment camber accurate 2. review best android free app angle automotive alignment camber accurate
Some hits from the iOS searches are as follows: A. Wheel Align for ALiSENSOR Wheel By Gloi AB https://itunes.apple.com/us/app/wheel-align-for-alisensor/id513879710 B. iHandy Level Free By iHandy Inc. https://itunes.apple.com/us/app/ihandy-level-free/id299852753 C. Clinometer + bubble level + slope finder (3 in 1) By Peter Breitling https://itunes.apple.com/us/app/clinometer-+-bubble-level/id286215117
Some hits from the Android searches are as follows: A. Clinometer + bubble level By plaincode https://play.google.com/store/apps/details?id=com.plaincode.clinometer B. iHandy Level Free By iHandy Ltd. https://play.google.com/store/apps/details?id=com.ihandysoft.carpenter.level C. Angle Meter PRO By nakhon phagdeechat https://play.google.com/store/apps/details?id=iyok.com.anglemeterpro
The amount of useless responses to this thread can be minimized simply by asking those who don't care to or who haven't ever successfully checked their camber at home to NOT respond (they're not going to be able to tell us anything we don't already know - all they're going to do is clutter up this thread to make it harder to be useful to others).
However, if you have ever attempted to check your camber at home using a smart phone angle measuring tool, your insight, hints, and advice would be greatly appreciated (and would be generally useful to many people).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ooooops.

I had forgotten to link to a descriptive photo of the desired task:
http://i.cubeupload.com/6CPUl7.jpg
I'm sure there are gotchas (e.g., is the garage floor really flat?), but it seems doable to measure camber at home if we can answer the main obvious questions which are (I think):
Q: What accuracy is *needed* to measure camber at home? Q: What accuracy can be *attained* with a typical mobile device? Q: Is the repeatability sufficient in a typical home measurement setup? Q: How do we compensate for typical errors (e.g., ride height, flat floor)?
What other gotchas will we need to look at to successfully measure wheel camber using a mobile device in a typical garage setup?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John Harmon wrote:

.01 degree or better.

?????????? don't use one myself

Same way you do with the machines, Measure the floor and level the machine prior to use. Using an app you could check the floor span where you plan to do the work and zero it out.

How to attach the device to the wheel/hub.
--
Steve W.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@yahoo.com actually said:

We really must know to what accuracy we need the measurements to be becuase every measurement tool ever made has this as its basic issue.
Do you think it's less, or more accurate that we need for camber measurement?
As just one reference, page 8 of this document says that camber (and toe) measurements must be accurate to "2 angular minutes". http://www.bimmerboard.com/members/snitch740i/original/BMW_Wheel_Alignment_System%5B1%5D.pdf
The question then becomes how to translate 2 angular minutes into inch measurements.
On page 10 of that document it says the camber tolerance of another vehicle model is ? 10' (plus or minus 10 minutes).
So what is 10 minutes in inches?

I realize there are many ways to measure things, and I understand that you're using the tire wear and handling to measure camber, but I would like to try to get a bit finer in granularity (especially since lots of other things can cause both those issues).

I have plenty of carpenters bubble levels, one with digital output, so that's also another option.

I understand what you're saying which is that the negative camber on my rear tires can be anywhere between 0 and minus 2 degrees.
But I would like to get a bit more accurate than 1/4 bubble! :)
One of my cars specifies the following static camber range, for example: Front (non-adjustable) camber = -0.7? minimum, 0.3? maximum Rear (adjustable) camber = -2.2 ?mimimum, -2.0? maximum ( http://www.bmwdiy.info/alignment/index.html )

Some cars compensate for that by specificying cross camber specs, but mine are symmetric.
The static negative camber is "supposed" to increase lateral grip. At the same time, it certainly increases inner tire edge wear and decreases straight-line braking traction. On uneven road surfaces, you can get camber thrust (where the tire moves toward the camber).

Yup. That's a measurement and calibration issue for sure, but luckily, my garage is extremely flat (I measured it once long ago).

That's excellent advice. Since the tire bulges, I wonder if it's best to use the wheel lugs to mount a jig which is what we measure to?

This is a good hint, which is that we can just note what the *delta* is between the front and back, and measure that delta, over time, with a handy instrument.

Mine has negative camber on both front and rear, but front isn't adjustable without adding camber plates.

I disagree but I understand your point. On sheer economy, there are only 3 measurements I need for my sedan: 1. toe front 2. toe rear 3. camber rear
So all I need, to do a "pragmatic" alignment check, is to check those three. A. If they're off, then I can get the car aligned for $100 or more. B. If they're on target, then I save $100 each time I measure them.

On page 14 of the document above, it tells me that the static toe and camber accuracy needs to be: Toe measuring accuracy ?2' in measuring range ?2? in total range ?18? Camber measuring accuracy ?1' in measuring range ?3? in total range ?10?
http://i.cubeupload.com/cfaDWp.jpg
Does anyone here know how to convert the 1 and 2 minutes to inches?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/8/2016 2:12 PM, John Harmon wrote:

A jig, if you can't use the actual wheel.

No, But 30 min is equal to 0.5 degrees. Mikek
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
amdx actually said:

I agree that, for our purposes, we should assume I jury rig a jig of some sort so that there is a flat completely perpendicular plate bolted onto the axle somehow (probably placed on the outside of the wheels using the lug bolts or lug nuts).

Right. And the 1 and 2 minutes are 1/60th and 1/30th of a degree respectively.
But what is 1/60th of a degree in inches?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/8/2016 3:13 PM, John Harmon wrote:

That depends on the length. Mikek

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
amdx actually said:

Following that statement to the logical next step, here is a representiative track for my sedan from this thread: http://www.bimmerforums.com/forum/showthread.php?1312326-1998-BMW-528i-Complete-FRONT-Suspension-Overhaul
That photo says that the track is: - Front Track Width = 1512 mm - Rear Track Width = 1526 mm
So now what's 1/60th of a degree, in millimeters?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/8/2016 6:54 PM, John Harmon wrote:

You have a misunderstanding, to figure millimeter or inches, you need to have two lines that are connected like a below,
l****/ l / l / l / l/ The angle between l and /, we will call 1/60 of a degree, the **** is the millimeters or inches, BUT, the quantity of millimeters or inches depends on the length of l, as you can see the longer l the larger **** will be. But the angle stays the same.
Use the link below may help you see it.
http://www.carbidedepot.com/formulas-trigright.asp I put in a 1 degree angle for (angle a) and 16" for (side B) Then hit calculate to find (side a). This says you need 0.279" of tilt top to bottom on a 16" wheel. Note: this triangle is rotated 90* to your wheel. So take that into account when thinking about the calculation. Bottom line, for a 1 degree angle you need a tilt of 0.279" over 16". That's measurable, but you need a post 90* off the floor to measure from. Second note: Side (a) the tilt at the top (mm or inches), Side (b) is perpendicular to the floor, Side (c) would be the tilt of the wheel. Angle (a) is the degrees of the angle you set.
Mikek
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/8/2016 7:36 PM, amdx wrote:

Just Repeating so you don't miss my post. I would like to know if my explanation made any sense to you. Be sure to use the trig calculator to help you understand. Maybe even draw out a few right triangles get the idea

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
amdx actually said:

Nice graphic!
To your point, I completely agree that I'm utterly confused when it comes to "toe" angles.
It was my mistake to ever bring in the concept of "toe" to this discussion because, while measuring toe with a tape measure at home is relatively easy (once the mechanical overhang problem is solved), *converting* the damn manufacturer's spec from angles to inches is the *confusion* I have.
Here is the toe spec for a similar vehicle to mine:
http://i.cubeupload.com/RubZhV.gif
Notice that the "total toe" spec is 0 degrees 14 minutes plus or minus 10 minutes.
Also notice that the measurement accuracy for "total wheel toe" is also given in similar units of a measuring accuracy of plus or minus two minutes in a measuring range of plus or minus two degrees within a measuring range of plus or minus 18 degrees.
http://i.cubeupload.com/cfaDWp.jpg
I admit I'm confused. My dilemma is understanding how to *measure* to that spec.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/08/2016 3:13 PM, John Harmon wrote: ...

Incompatible...one is an angle, the other a distance.
As _amdx_ points out in another subthread, you've got to convert an angle to a distance via trig relationship of the angle you're measuring to the corresponding length of the appropriate side of a right triangle.
He posted some values there, but 1 minute subtended over 16" length of diameter of a rim is an offset of only 0.005" difference from vertical of the top/bottom edges. That does seem to be absurd precision to expect.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
dpb actually said:

Except that the manufacture specifies toe in angles but I would measure toe in distance.
http://i.cubeupload.com/RubZhV.gif
http://i.cubeupload.com/cfaDWp.jpg
Hence it's obvious to all that I am confused how to do that.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

For small angles sin(A) = A (provided A is in radians) and d times sin(A) (hence d times A) is the displacement at a distance d caused by an angle a. To convert to radians, multiply degrees by .0174532925199 (pi/180).
For example, 2 minutes = 1/30 deg = .0005817764173 radians so 8 inches from the hub that corresponds to a displacement of 8 * .0005817764173 .00465 inches or 4.65 thousandths of an inch (0.118 mm). I image that's hard to measure.
The suggested accuracy of 0.01 degrees corresponds to a displacement of 3.5 micrometres at 8 inches. That's less the typical width of a human head hair.
--
Ben.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 8 Dec 2016 21:13:33 -0000 (UTC), John Harmon

That depends whether it is at 12.5 inches, 12.5 feet, or 12.5 miles....... You REALLY need to study your high-school math.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@snyder.on.ca actually said:

This off-topic confusion is all my fault.
I should never have brought toe into this discussion because toe is easily done at home when you have specs that are in linear dimensions such as inches but not so easily understood when you have toe specs in angles.
http://i.cubeupload.com/RubZhV.gif
http://i.cubeupload.com/cfaDWp.jpg
Clearly I'm confused how to do the conversion.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/9/2016 11:20 AM, John Harmon wrote:

Ya, I am to. But first let me say this, The first spec you posted, 0* 14' plus or minus 10', seems this isn't as critical as some posters are making it. For toe, it is still a trig problem, but the problem is defining, side b (a reference point).
> http://www.carbidedepot.com/formulas-trigright.asp
I wonder do the shops attach a laser and measure on a wall scale a defined distance away?
I don't know this, is it a single adjustment that moves both wheels or do you adjust both wheels separately? (makes a reference even more important) Sorry just thinking on the keypad.
You have a trig problem and a measurement problem. The measurement problem is more difficult.
It is not be hard to convert the 14 minutes to inches using the wheel diameter as one line. The angle is how much more is the front of the wheel turned in more than the rear of the wheel. I'll call the wheel 16" from front to rear. (just realized this almost the same trig problem for camber, just rotated 90*)
I'm using the trig calculator above, this time the orientation is correct. Put the following numbers in, (side c) = 16, (angle A) = .233. The angle is .233 because 14min/60min = .233. Your answer is (side a) which is 0.065". So, you want the rear of a 16" wheel stick out 0.065" more than the front. Not real easy to measure, But, if you could extend the 16" to 12 ft (192") with a laser pointer, then (side a) is 0.781". The laser must be perfectly square with the wheel. Just some thinking. Hope it makes some sense. Mikek
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
amdx actually said:

Now that I've done some more research, I have a better handle on 'toe' so I'm going to agree with you that getting toe precise to 2 minutes isn't all that important, in all likelihood.
For *setting* toe, especially in the rear, it could easily be that 0 toe (degrees or inches) would be just fine, or, maybe, to take up some suspension slop, a "smidgeon" of toe (maybe 1/16th of an inch or less in linear dimension no matter what the wheel/tire diameter).
This is to take up the slop in the suspension (perhaps slightly more in the front if it's a typical RWD like all my vehicles are).

I'm still confused how to convert toe from degrees to inches, but luckily, there are web sites that will do it for us. https://robrobinette.com/ConvertToeInchesToDegrees.htm

Interesting you mention that, because the reason for the *far away* wall is simply that the angle is small, right?

If you are talking about toe, I'm no expert, but the way I understand it is that you lock the steering wheel in the center position first (which has nothing, per se, to do with alignment but with esthetics) - and then - you pick a side, and twist a tie-rod ever so slightly - which - depending on the direction of twist, moves the front of the wheel in toward the centerline of the vehicle - or outward.
So it's one wheel at a time, measured to the centerline. Of course, you can assume all sorts of symmetries and do both wheels at the same time, but conceptually I think of toe as a wheel-to-centerline thing, to be done one at a time.

That's an interesting observation that the measurement problem is more difficult, but I think only if we try to measure degrees of toe.
If we measure inches of toe, the measurement problem is conceptually trivially simple.

I'm trying to find the triangle in the equation of toe in order to figure out how to convert the distance measurement to an angle.
Here I just drew what is my first pass guess at where that triangle lies:
http://i.cubeupload.com/ZmdfeN.gif
Is *this* the trigonometric angle everyone is talking about?

You make a good point here in that we really have a 3-dimensional X, Y, and Z axis, each of which is rotated by 90 degrees (caster, camber, and toe).

Just to ask to get me more firmly grounded, is *this* the triangle everyone is talking about?
http://i.cubeupload.com/ZmdfeN.gif
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@snyder.on.ca posted for all of us...

+5 and high school math... He could go back to school and learn all this for less bux than he wasted-not to mention our time.
Drive it to the BMW shop and tell them you want it set to the preferred settings. Make certain all your bushings and arms and their esoterically named crap is brand new because as it wears it will change. Don't hit any curbs, potholes, driveways, obstructions of any sort, or drive it period. Better get new springs too as they will sag and take everything out of the trunk. If it's a convertible weld some stiffeners along the top. Have your partner and you control their weight. Fill up with gas first. Get all pebbles, stones and other safarcus out of the treads. Make certain the tire pressure is within a 10/th of a pound. I am sure I am forgetting something...
--
Tekkie

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I too am starting to wonder if this guy is nuts, or maybe just a troll. There is some very simple math involved here.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.