What can you do with a cell phone?

[BDA]

I think the (what I call the) angle at "hard points" is to give you the equivalent of the parallel strings required of Roginette's Alignment Calculator. In the case of the Gyraline tool, whatever angles you produce on both sides of the car are to fix the centerline. I don't know that but I can't imagine it meaning anything else. So I think those angles have to be taken from points that are known to be equidistant from the centerline? I further guess that it takes angles from both sides rather than from one side with the width of the car (because the tool only measures angles)... As I say, I'm guessing but I plan on asking them about it.

[EuropaTC]

Well, after watching the video on their website I've got to admit I have no idea how that's working.  But as I am only slightly more technically advanced than a dinosaur, perhaps that's not surprising and I need an 8yr old to explain it for me....

I can see how camber and castor works but watching how the guy measured wheel alignment on his MR2, well, I'm stumped. If this is as accurate as they claim then there's some very clever maths and sensors at work and I'll admit I'd like to see the maths they've used.

As you know, I've also used the Robinette calculator and figured out the maths that allows for an offset string box, but that relies on knowing the front & rear track IIRC. I can't see from the Gyroline video how they get that number unless I missed them inputting the data further down the video. Also I'm not convinced that taking an angle from the window or body panel is good enough. Heck, I wouldn't trust 1960s Lotus to have the body symmetrical to within half an inch across the centreline !

Having said all that I've got to say that the accuracy claims are simply amazing. I've got a reasonably expensive digital level/angle finder but  the 0.01deg they claim is pretty stunning for something that's measured using a cell phone. At that level I'd be wondering about the accuracy of the 3D printed carrier !

https://gyraline.com/pages/study1

[BDA]

I THINK I know what it's doing (at least in the simple cases). The front toe is done by defining a "reference" plane when you "measure the angle of the first wheel." You really aren't measuring anything, you're just defining the plane that the next wheel angle measurement is in reference to. So I think you get something very similar to what I get when using my Dunlop optical toe gauge. You just get the angle between the two front wheels.

The real problem is the thrust angle and the rear toe. The angles measured from some points on the car (in the Body Mode video here: https://gyraline.com/pages/how-to-videos) are used to define the centerline or center plane of the car. I think it has to assume each of the angles are the same with respect to the centerline. If the angles diverge toward the front of the car, it calculates the intersection toward the rear of the car and vice versa if the angles converge toward the front. If the angles are parallel to each other, then you have Robinette's situation. Apparently, it has the ability to programmatically define a reference plane. It should be able to deal with knowing where the centerline of the car is or that there is no defined centerline because the angles are parallel.

My concern, as I said before, is that I don't trust that any panel or windows on either side of the car to have the same orientation to the centerline because of the sloppy tolerances at Lotus. I haven't taken off a rear wheel but I think the frame is exposed enough to take a measurement for "Body Mode" there so I sent them a message asking if hose measurements can be stored and retrieved later. It would be VERY cumbersome to take those measurements, put the phone in the gyraline tray aside, put the wheels back on and then resettle the suspension to do the rest of the measurements every time you did a rear toe measurement. And since those "Body Mode" measurements don't change, it would be nice to do it once for every car and store them for future retrieval. So far I haven't heard back. I'll report back when I do.

[Bryan Boyle]

Everybody knows about using a cell phone for GPS, speedo, streaming music, or even to make a phone call but I recently came up with some others. I was at a friend's house who had an bore scope and I thought that was pretty interesting so I bought a USB endoscope for my cell phone. The only difficulty was finding the app that produced the best resolution but I found a good free app and now I have a bore scope/endoscope that cost me about $20! Literarymadness came up with another use for the endoscope and that was to be able to read the numbers stamped on my flywheel. They are small and my eyes have a hard time reading them from even as close as I can get to it. Another use would be to inspect the inside of a frame.

I was watching some videos on using a leakdown tester on youtube and some of people used a microphone to amplify the sound of air leaking so I thought a microphone would be another good addition to my cell phone. I got the mic from Amazon for about $6 and found a free app that routes the sound to the cell speakers, provides graphical sound wave, and supposedly will record the sound (I haven't tried that yet). It is very sensitive such that I have to worry about reverb as well as how noisy it is in the garage (eg. the compressor must not be running!).

Can anybody come up with new uses for those tools or other tools you can use with a cell phone?

Just bought this:

https://gyraline.com/

It works.  Came up with the same toe settings in my garage that the specialist alignment shop set my car to.  It works. 

[BDA]

I assume you checked out your rear toe. What did you use as your "reference" since the frame isn't accessible without taking the wheels off?

[Bryan Boyle]

I assume you checked out your rear toe. What did you use as your "reference" since the frame isn't accessible without taking the wheels off?

Just to test...I used the lip edge of the boot opening.  It's parallel side to side; I measured the opening in 3 places and it's the same.  (now, whether to the car frame or is centered in the body or not is a different story...probably not after all this time). 

I'm thinking that this is a good quick check of the basic alignment of the car...but, putting it on a laser rack with someone who knows what to do and how to do it is still the best.  But finding someone that can translate the inch measurement into the degree angles that most new racks give measurements in is a bit of a searching hassle.

But I'm ok with what the gyralign came up with.  A lot easier than strings, jack stands, tape measures...and how my car rides down the road (take the hands off and it tracks straight, and friends who've followed me didn't mention that it was dog-tracking) is just fine at this point.

[BDA]

Thanks for your comments about the Gyraline. I wasn't worried about it for a steel car - especially a "modern" one, but I was worried about getting a good reference angle on a 50 year old Lotus. I did think that maybe the crease under the 'B' pillar might be a good place to take that angle. I didn't think about the boot opening and having at least two choices makes getting one an easier decision.

Translating from inches to degrees can be done here (https://robrobinette.com/ConvertToeInchesToDegrees.htm)
And from degrees to inches can be done here (https://robrobinette.com/ConvertToeDegreesToInches.htm) if that helps.