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:

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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

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B. iHandy Level Free By iHandy Inc.
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C. Clinometer + bubble level + slope finder (3 in 1) By Peter Breitling
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Some hits from the Android searches are as follows: A. Clinometer + bubble level By plaincode

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B. iHandy Level Free By iHandy Ltd.
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C. Angle Meter PRO By nakhon phagdeechat
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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).

Reply to
John Harmon
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Ooooops.

I had forgotten to link to a descriptive photo of the desired task:

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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?

Reply to
John Harmon

.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.

Reply to
Steve W.

0.01deg ?? I don't think so...

If your car doesn't pull to one side and the tire is not wearing un-evenly, the camber is fine. I have used an ordinary carpenters bubble level to check it.

If it is within 1/4 bubble it should be OK. Most roads have crown so the camber is not as critical as you might think.

Problems with this method are:

1 ground where the car is parked needs to be both flat and level

2 ordinary tire bulges out on the bottom, need to set the level against the tire away from the buldge

Sometimes you can simply compare the reading on the front wheels to the back wheels.

Also note many cars are designed to have the front wheels tilted inward at the top slightly for stability

Unless you like this as a hobby, it probably doesn't pay to DIY.

Measuring toe in is much more fun.

Reply to
makolber

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".

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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 (

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)

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?

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Does anyone here know how to convert the 1 and 2 minutes to inches?

Reply to
John Harmon

Thanks for that answer because this is a critical number we must know to do any aligment reasonably well.

If everyone concurs that 0.01 (one hundredth) of a degree is the desired accuracy, I can work with that.

One problem with alignment is that we have to be intelligent about converting units because I found this document where, on page 11, it says: [quote] Quick-acting clamp + measuring sensor + computer = 1' at a measuring range of ? 3? (all BMW vehicles are within that ? 3? measuring range). [/quote]

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But I don't (yet) know how to convert 1 minute to inches. Does anyone want to take a stab at how to run that conversion?

It seems to me that a "jig" of some sort needs to be made so that there is a plane on the wheel that is (very precicely) parallel to the wheel to the same 0.01 inches that we need for accuracy.

My initial idea is to take this concept to that 0.01 degree:

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Maybe bolt a flat steel plate to the wheel lugs (luckily, one of my cars uses lug bolts so I can just use longer bolts but my other car uses lug nuts which may make that flat plate bolting on more difficult).

Reply to
John Harmon

I assume that is the wheel and not a hub cap. I'm guessing your looking for something between 0.5* and 2*, but I want to know. Someone said you need accuracy within .01 degrees, that's 1% of 1 degree. Good luck getting the 18 year old at the tire shop to do that. I'd be happy with 10%, being that it is an adjustable characteristic that can depend on how you want to drive the car, comfort or cornering. I don't have a clue about phone app accuracy, but you can check it. But hey, I've never done it, so don't read my response.

Mikek

Reply to
amdx

The car I will test this out first on is a bimmer with alloy wheels and lug bolts so both those traits make the task of bolting on a jig easier than if it were a steel wheel with lug nuts.

I later found this BMW spec which shows that I need accuracy in 1 or 2 minutes (

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) but how do I convert that 1 and 2 minutes to inches?

I think he meant inches though.

I understand that the alignment shop guy might not care all that much to get as accurate as he can.

Right now, I think the accuracy needs to be plus or minus one minute for toe and 2 minutes for camber.

I just don't know how to convert minutes to inches.

Reply to
John Harmon

snipped-for-privacy@yahoo.com posted for all of us...

+1 at least
Reply to
Tekkie®

According to this graphic, I need to repeatably measure toe to plus or minus 2 minutes of accuracy and camber to plus or minus 1 minute of accuracy:

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Static camber will be measured in degrees, so the plus or minus 1 minute of accuracy is easy enough for me to understand.

But sttic toe is usually measured in inches, so a problem is how do I convert the 2 minutes of accuracy to a plus or minus inch figure?

Reply to
John Harmon

According to this graphic, I need to repeatably measure toe to plus or minus 2 minutes of accuracy and camber to plus or minus 1 minute of accuracy:

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Static camber will be measured in degrees, so the plus or minus 1 minute of accuracy is easy enough for me to understand.

But sttic toe is usually measured in inches, so a problem is how do I convert the 2 minutes of accuracy to a plus or minus inch figure?

Reply to
John Harmon

"John Harmon"

You can't. Minutes of angle are a function of a triangle. Inches are simply a scalar measurement of distance.

Reply to
Phil Kangas

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

No, But 30 min is equal to 0.5 degrees. Mikek

Reply to
amdx

That's bad news because both the toe and camber are specified in degrees but when I measure toe, it will be in inches.

At least when I measure the camber it will be in degrees so I won't be switching units back and forth.

I know how to physically measure toe in inches (e.g., with a string); but I don't (yet) know how to measure toe in degrees with a smart phone or digital level.

Reply to
John Harmon

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?

Reply to
John Harmon

Something wrong, 30 minutes is equal to 0.5 degrees.

1 minute is 0.0167 degrees, I don't think that's what you are after.

You might play with a trig calculator.

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.

Mikek

Reply to
amdx

That depends on the length. Mikek

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Reply to
amdx

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.

Reply to
dpb

one of the links you provided above shows a guy using a sting with a weight to define vertical and then a ruler to measure the distance to the wheel.

He also showed the math to convert distance to angle.

It depends on the height of the tire.

Its basic trigonometry sine = opposite / hypotenus. which is close enough for small angles

so using a calculator if the top of a tire is 20" off the ground and over that distance it tilts in by 1"

using a calculator inv tan(1/20)= 2.9 deg

thats inverse tan or arctan of 0.05 = 2.9 degrees

be sure the calculator is in degrees mode, not radians.

arcsin instead of arctan is opposite / adjacent which for small angles is almost exactly the same.

or we can work it the other way round

lets use 1 degree

tangent of 1 deg

tan(1) = 0.017.

So for every 10 inches of tire height, the tilt inward will be 0.17"

get it? m

Reply to
makolber

Sort of mixed units.

For a circle with radius about 286.5 feet your circumference will be about 21,600 inches so each minute of arc will be one inch. I don't think that helps you here.

Reply to
AMuzi

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