Random assortment of stuff I have used and still use.
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Current Recommendations On Home Wheel Alignment Equipment?
- Thread starter MDchanic
- Start date
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Yes, I understand that caster is calculated. I don't know the formula for calculating caster from caster swings though. I guess I should have asked Rusty how he was "calculating" caster with the tools he was using. I did fabricate a tool to measure caster directly for a project I was doing.
This thread will help....
Alignment at home and aftermarket UCAS too.
I bought a gauge and have aligned a few cars with the setup for about the cost of 1 or 2 professional alignments that may or may not have been what I asked for.
Alignment at home and aftermarket UCAS too.
I bought a gauge and have aligned a few cars with the setup for about the cost of 1 or 2 professional alignments that may or may not have been what I asked for.
Easy. The complication comes when you get away from the "common" measurement with the wheels "in" and then "out" at 20 degrees from straight ahead. You take camber (tilt) readings at those wheel turn angles, subtract them, and then multiply by 1.5. That is your caster. If you for some reason do not or can not turn the wheels 20, then you'll have to search up the formula for different angles. It's just not that hard.
Main thing is to make sure the suspension is "jounced" and is not "bound up" (which actual turning plates help take care of, that you actually turn the wheels fairly accurate to 20 degrees, and of course that you are actually measuring wheel camber (tilt) fairly accurately. For example, whatever you use for a tilt guage or even a real caster/ camber gauge IT MUST BE ROTATIONALLY PLUMB If you look at most any of these, they have a "to front and to rear" level bubble to level the gauge in that direction.
With a level and an angle finder. Sorry, I missed it till now.
Longacre gauge....
Instructions....
You can attach the gauge to the flat spot on the wheel hub or do as I did and make a mount.....
Instructions....
You can attach the gauge to the flat spot on the wheel hub or do as I did and make a mount.....
MDchanic
Connoisseur d'Junque
When I was younger I used to use one of these (Hunter brand, I think), so I know how those work:
One thing I've noticed in all of the newer gauges posted on this thread is that the lack the spring-loaded needle-like pin that sticks out of the mounting surface, and is used to locate the center of the axle:
I always thought that ensuring concentricity was important to getting accurate measurements.
Is there a different way that those other gauges do that?
Thanks,
– Eric
MDchanic
Connoisseur d'Junque
Wow. That's a really great writeup!
I'm not ready to go that far right now (no appreciable front suspension wear when I disassembled it last year), but when I do...
Thanks!!
– Eric
My old Ammco has no such centering device
For camber the gauge just has to be parallel to the face of the wheel, the angle is the same across the whole plane so it can be anywhere you can get the gauge parallel to the wheel face.
For caster, because you're actually subtracting two different camber readings, you end up canceling out any input you might get from not being centered because the gauge is staying the same distance from the axis.
The centering pin, I believe, probably has more to do with making it hard for the gauge to move around during the measurement. An extra safety on the magnetic attachment. One of those nice things to have that isn't essential that has likely been deleted for cost. I'm just thinking out loud though.
MDchanic
Connoisseur d'Junque
Okay. That makes sense. I never tried to work any of this out on paper (if I could even remember how to - Geometry was a LOOOOOOONG time ago), so that's helpful.
Probably needed if you want to check for runout, though. I don't remember whether that was part of the process, but I do remember adjusting a thumbwheel that moved one level tube, then rotating the wheel and doing that again. I think. It's been like 30 years...
- Eric
Also just thinking outloud. I don't think it would matter on caster swings where the gauge is vertically as long as it is still centered with the hub. I'm not sure if that would hold true horizontally or front to back for caster swings. In my head I'm picturing an extreme for effect. If the gauge could be slid back from centered all the way to near the bead of the tire. I'm not sure it would read the same. I know this is not a realistic example, just an extreme for the thought experiment.
Runout has to be checked for the toe, if you’re using the wheel attachments/adapters for an optical gauge or similar. It also confirms that the wheel attachments are in fact parallel to the wheel face. But for camber and caster you should be able to see if the wheel adapters aren’t flush.
So the SPC fastrax gauge that I use basically reads off the bottom attachment at the lip of the rim, not at the center.
Because of the way it attaches it should still pass through center, but the gauge doesn’t even have a level going the other direction to confirm it’s parallel to the ground.
By zeroing the camber reading with the wheels turned, and then reading it turned the same amount in the opposite direction you cancel out pretty much all the geometry except for the angle of inclination which is your caster angle.
It’s been a long time for geometry proofs for me, but because you’re taking the difference between those measurements it cancels out a ton of variables.
Woody500
Well-Known Member
I've used 2 sheets of steel w/gear oil, but that sounds like an easier clean up, especially Crisco type lube. & throw away tiles if you want. How much is a box now?
I’ve never done my own alignments yet but am planning on doing one some time this summer. I plan to get one of these.
Gyraline Align-It-Yourself Kit
Gyraline Align-It-Yourself Kit
Interesting. I wish the link gave more info about how it works. Seems almost like magic.
I found this on the Gyraline
MDchanic
Connoisseur d'Junque
I decided against the Gyraline.
It's a neat idea, but I don't think it's fully developed yet.
The way it seems to work is by using the accelerometers in your phone, which seem to actually constitute a pretty good level, and, apparently, the compass.
You can see the level function if you never have before, by looking at the Compass and Measure apps on an iPhone (Android will have similar).
In Compass, there is a set of cross-hairs in the center of the compass which you can use as a level.
In Measure, there us a level function that reads out in degrees, but is a little odd in the way it reads in two axes at once.
So, if you wanted to, you could make your own phone-leveling jig, in any size you wanted, to act just like the Gyraline plastic jig, read out your camber angles in degrees, and calculate your caster angles.
As far as toe and measuring turn angles for caster calculations, I believe that the Gyraline uses the compass itself, which reads out in degrees of bearing. You could do this to measure how far you've rotated your wheels, to make caster calculations.
I am skeptical of the accuracy of the compass for making toe measurements, though.
If you think about it, though you are measuring toe in inches, it is actually a measure of degrees of rotation (inward or outward) of each wheel. Figuring a 25" tall tire, and a desired 1/16" of angle inward (1/8" total for both wheels), and converting that to metric to make the math simpler, you've got a 650mm tall tire that needs to be 1.5mm closer-in in the front than in the back.
Figuring a front track of 55.9" (1,420mm), this makes each wheel one corner of an isosceles triangle with a base of 1,420mm and two sides of 308 meters (1,000 feet) each, with angles at the base of 89.868°.
Even if I give the Compass application credit for being able to accurately measure 5 digits of precision on bearing, I have trouble believing that local interference from ferrous metals, electrical equipment, magnetic tools, etc. would not affect those measurements, especially when taken at two different places (the left and right wheels).
I'd trust the Compass application to measure 15 or 20° for my caster calculations, but not to measure 0.132° vs 0.264° to split the difference between 1/8" and 1/4" of toe and make sure it's even on both sides.
Going beyond the Gyraline's measurement technique, though, and even assuming that they have developed a way to use the defense industry's technology in cell phones to accurately measure the requisite angles, there is a larger problem.
The Gyraline measures exclusively from a pair of points along the edge of the rim.
There are two problems here.
One is that, while original steel MoPar wheels are shaped perfectly for this, more modern alloy wheels, which often have a smooth convex curve instead of a right angle, have nowhere to reliably, repeatably align the measuring jig.
The other is that this system locates off of the edge of the rim, but has no mechanism for correcting for rim runout (left-right variation or "wobbling" of the outside of the rim, compared to the hub). You can have a decent amount of rim runout on an older American car and not feel it at all, but you can sure see it if you watch the rim spin on a dynamic balancing machine.
If the rim, as it sits, deviates outward 1/16" at the top, and inward 1/16" at the bottom, that will make the measurements on that wheel 1/4° off just to start.
Remeasuring at different points on the wheel will give different numbers.
Measuring the other wheel will have the same effect.
And that says nothing about rims with minor bends in them, which will introduce even more variation.
The old magnetic bubble-level equipment, when used on old-style American steel wheels, measured directly from the hub, eliminating this.
Modern laser equipment, which does use a frame that clamps onto the outside of the rim, has a technique for compensating for runout variation, by having the car roll back and forth one wheel revolution to get a base calibration.
This equipment does neither, and I think that's a significant flaw.
Personally, I've decided to go with a pair of 50 year old American-made bubble units I found on eBay, and build a pair of toe frames using angle iron, and start there.
I am interested to know anyone's experience with the Gyraline, should they decide to get one, and, specifically, how repeatable its measurements are, especially after moving the car and re-measuring.
– Eric
It's a neat idea, but I don't think it's fully developed yet.
The way it seems to work is by using the accelerometers in your phone, which seem to actually constitute a pretty good level, and, apparently, the compass.
You can see the level function if you never have before, by looking at the Compass and Measure apps on an iPhone (Android will have similar).
In Compass, there is a set of cross-hairs in the center of the compass which you can use as a level.
In Measure, there us a level function that reads out in degrees, but is a little odd in the way it reads in two axes at once.
So, if you wanted to, you could make your own phone-leveling jig, in any size you wanted, to act just like the Gyraline plastic jig, read out your camber angles in degrees, and calculate your caster angles.
As far as toe and measuring turn angles for caster calculations, I believe that the Gyraline uses the compass itself, which reads out in degrees of bearing. You could do this to measure how far you've rotated your wheels, to make caster calculations.
I am skeptical of the accuracy of the compass for making toe measurements, though.
If you think about it, though you are measuring toe in inches, it is actually a measure of degrees of rotation (inward or outward) of each wheel. Figuring a 25" tall tire, and a desired 1/16" of angle inward (1/8" total for both wheels), and converting that to metric to make the math simpler, you've got a 650mm tall tire that needs to be 1.5mm closer-in in the front than in the back.
Figuring a front track of 55.9" (1,420mm), this makes each wheel one corner of an isosceles triangle with a base of 1,420mm and two sides of 308 meters (1,000 feet) each, with angles at the base of 89.868°.
Even if I give the Compass application credit for being able to accurately measure 5 digits of precision on bearing, I have trouble believing that local interference from ferrous metals, electrical equipment, magnetic tools, etc. would not affect those measurements, especially when taken at two different places (the left and right wheels).
I'd trust the Compass application to measure 15 or 20° for my caster calculations, but not to measure 0.132° vs 0.264° to split the difference between 1/8" and 1/4" of toe and make sure it's even on both sides.
Going beyond the Gyraline's measurement technique, though, and even assuming that they have developed a way to use the defense industry's technology in cell phones to accurately measure the requisite angles, there is a larger problem.
The Gyraline measures exclusively from a pair of points along the edge of the rim.
There are two problems here.
One is that, while original steel MoPar wheels are shaped perfectly for this, more modern alloy wheels, which often have a smooth convex curve instead of a right angle, have nowhere to reliably, repeatably align the measuring jig.
The other is that this system locates off of the edge of the rim, but has no mechanism for correcting for rim runout (left-right variation or "wobbling" of the outside of the rim, compared to the hub). You can have a decent amount of rim runout on an older American car and not feel it at all, but you can sure see it if you watch the rim spin on a dynamic balancing machine.
If the rim, as it sits, deviates outward 1/16" at the top, and inward 1/16" at the bottom, that will make the measurements on that wheel 1/4° off just to start.
Remeasuring at different points on the wheel will give different numbers.
Measuring the other wheel will have the same effect.
And that says nothing about rims with minor bends in them, which will introduce even more variation.
The old magnetic bubble-level equipment, when used on old-style American steel wheels, measured directly from the hub, eliminating this.
Modern laser equipment, which does use a frame that clamps onto the outside of the rim, has a technique for compensating for runout variation, by having the car roll back and forth one wheel revolution to get a base calibration.
This equipment does neither, and I think that's a significant flaw.
Personally, I've decided to go with a pair of 50 year old American-made bubble units I found on eBay, and build a pair of toe frames using angle iron, and start there.
I am interested to know anyone's experience with the Gyraline, should they decide to get one, and, specifically, how repeatable its measurements are, especially after moving the car and re-measuring.
– Eric
TheTieWrapKid
Well-Known Member
I have an old Manco stiff aluminum sliding analog pointer gauge for setting toe. Works pretty good for me. I double and triple and quadruple check my readings. I have an old Halibrand camber gauge which was good for 13 to 15 inch rims and I recently modded it to handle 16 inch rims, which a couple of my more modern drivers have. It has caster instructions with formulas to figure caster from the camber sweep readings. Also some way to mark 15 or 20 degrees out or in from straight. Not so long ago I made sure I received the Tenhulzen alignment plates for Christmas. Also uses plates for toe readings with the tape measures and slots. These are good for a larger rim size range. 12 to 20 I think. I have a 2009 Challenger which has real tall wheels. I modded this Tenhulzen camber plate also so I could offset the measuring screws to allow fitting the tool in under the front fender to get on the wheels of the 71 Challenger and the 72 Duster. It will fit all my stuff now. The camber calibration is off a little between the Halbrand and Tenhulzen. The Halibrand was showing a little less camber. I am using the Tenhulzen number and using a cal factor number on my Halibrand unit. I still haven't tried measuring toe with the new Tenhulzen plates, but I'll work that in sometime. I have done front end rebuilds on these old Mopars and just want to have some idea how to set them up on alignment. I have learned a ton from many knowledgeable people on this site and am always checking in on the Steering and Suspension section.
MDchanic
Connoisseur d'Junque
Update:
I've got a pair of Caster-Camber levels.
Decided to go with old Made-in-USA ones over new Chinese ones.
A bit more expensive, but not bad.
Got a pair in their boxes for $200 (plus $57 shipping – the lady schtupped me pretty hard on that).
Looks like they're from 1974, as that's the latest model year on the chart.
Here's a modern listing for the same tool [edit: with a greater adjustment range], new
(just a single one, not a pair):
Interestingly, it looks like the manufacturer went out of business about ten minutes ago.
I've got a small pile of aluminum channel pieces. Think I'll use them to learn me some aluminum welding, and see if I can make up a pair of frames for measuring toe.
I may not get to it right away (gotta buy some aluminum TIG rod), but I'll post up when I'm done.
– Eric
I've got a pair of Caster-Camber levels.
Decided to go with old Made-in-USA ones over new Chinese ones.
A bit more expensive, but not bad.
Got a pair in their boxes for $200 (plus $57 shipping – the lady schtupped me pretty hard on that).
Looks like they're from 1974, as that's the latest model year on the chart.
Here's a modern listing for the same tool [edit: with a greater adjustment range], new
(just a single one, not a pair):
Interestingly, it looks like the manufacturer went out of business about ten minutes ago.
I've got a small pile of aluminum channel pieces. Think I'll use them to learn me some aluminum welding, and see if I can make up a pair of frames for measuring toe.
I may not get to it right away (gotta buy some aluminum TIG rod), but I'll post up when I'm done.
– Eric
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