Hi again guy's. A while ago I had a thread running asking advice on getting my front suspension back to stock ride height, I had hoped to pull it apart once. Didn't work out that way. However I got there in the end.
once the car came down an inch and a half. It is clear that the lower ride height has effected the camber of the front wheels. Gaining a noticeable amount of negative camber.
Now to my question. As the wheels go up into the fender as it where. The camber go's more negative, and as the wheels drop away, the camber go's positive. BUT. what happens to the toe? At some point in the "swing" the tie rods would be approximately level, and above and below level one would think toe would increase. That is more toe in. But at what point would that be?
just trying to get my head around just how much lowering my car back to approximate stock ride height has or could have effected the toe.
And also not clear if any effect on castor.
the car was sitting about an inch and a half high. Just a couple years ago, did a very, very thorough 4 wheel alignment on a friend's machine. Took us the better part of a day. Not wanting to put said friend out like that again. Getting the camber back looks easy enough .
just wondering about the effect on toe.
Perhaps someone could shed some light on this. Sorry I work on Motorcycles for a living, rake, trail , bearing preload. Not castor, camber and toe.

 

No expert on this subject, but I would not think TOE would be affected much, as the steering members are meant to flex due to tire up/down movement. My overall advice would be to have the front end aligned whenever you make significant changes to the front suspension.

 

There is a lot of bumpsteer in the C3 stock suspension design. Probably around 1/4" toe for the range of suspension travel.

IIRC, when lowering a C3 the front toe goes more toe-out. So if raising the car back to stock height specs the front toe will go more toe-in. (again, from memory so may be incorrect, there are tons of past threads on the topic, search "bump steer")

Since all you are concerned about is toe then you can probably get away with any national franchise $50 alignment special as all they will do for that price and a 20 minutes shop time is toe (a "toe-and-go" in industry speak).

 

Well, I will be doing this myself. You haven't seen the quality of people working in most tire shops in Australia. Not interested in letting them test drive my car. Getting camber back should be easy enough. Just take out equal amount of shim on both front and rear A arm studs. Then I guess I'll have to find a method to accurately measure the toe. I'll surch "Bump Steer" and see what I find.

 

Measuring Alignment (DIY) isn't that difficult, all you need is a few simple tools. For camber / caster you could get away with a simple IPHONE,

Here is how I DIY Alignment.

https://www.corvetteforum.com/forums...nt-method.html

 

Yes I remember your DIY alignment thread. I've read it before. You talk about the string method, but don't explain it. The method you do explain means going out and buying stuff I may never use again. And to be honest, I get totally lost half way through. I'm fairly certain I wont stuff up the caster if I adjust the camber by taking out equal shims on both A arm studs. Thought I'd just use a short level. Aim for real close to plumb. Getting the toe adjusted correctly is more of a concern. Although I must say the car is handling fine at the moment.

 

Buying this "stuff" will be less costly than ONE time at an alignment shop, that most likely has no idea what they are doing on a C3 Corvette and will actually screw it up. And the "string" method is not a very accurate method, although it will get you close. If you actually drive the car, as opposed to sitting in a garage for 29 days out of the month, you will need to check and adjust alignment more than once.

 

O.K., so I went out to the garage tonight. Pulled one med thickness shim from each of the 4 upper A arm studs. Retighted my spreader bar. Rolled the car back and forth a couple times. My level says "Damn I'm close". Still thinking I shouldn't knock the caster doing it this way. By eye, it looks like my wheels are toed out. Sound right? Been thinking over the string idea. Thinking I'll give it a try. First I want to double check my front wheel bearing adjustment. Any tips on measuring the front toe without buying lasers and cutting boards ?

 

I didn't mention (how to) string method because its all over the internet on how people do this. Also I found the results very poor and it takes way to long (setup) to get poor results.

Using the method I use takes 5 minutes to take all readings. Camber / Caster / Toe front and rear.

All the parts you need are very inexpensive.

Mounting bar for the laser ( basic tube steel)
Rulers total 4 were $5 each but you could make from 2x4 lumber and cut them all to the same length

Laser level was $30 dollars, find the cheapest laser level and make sure on the mounting to the bar. Mine have a magnetic base so they just stick to the metal bar.

The measuring bars can just be a measuring tape ( 2 required )

The level (camber / caster) can be as simple as a phone app.

All the parts are less than the cost for someone to attempt a C3 alignment at a shop.

When I first started this process I made everything from scrap parts to test the process. My mounting bar for the laser was made from scrap wood and taped the laser to the wood.

Rules were scrap 2x4's and used a basic measuring tape. The laser level @ $30 was the most expensive piece.

 

Well. Tried once again reading that thread on multiplying this and shooting a laser at that. Totally lost me yet again
can't for the life of me understand how shooting a laser off my rear wheels I KNOW are toed in can help me measure front toe.
I spent hours on a proper 4 wheel alignment machine. Take it off, drive down a bumpy road. Put it back on. Reset the heads. Re-measure. Reset. Repeat. Till we were happy this was as good as we could get it. YES rear toed in slightly. So taping a lazer to a stick? Mounting said stick to a tire that I know isn't square. Makes absolutely no sense at all to me. Just want to messure front toe.
everything I find on the net is for solid axle rear cars that run strings from the back of the car to in front of the car. But once again. I know my rear wheels are toed in.
I have an idea.
I started with adjusting my tie rods 1/4 turn longer. Knowing by looking at my car, by eye I can see they were toed out. Thinking 1/4 turn each tie rod was a good place to start. Tomorrow I'll do my own version of a front end only string method. I'll put up some photos.

 

For a string alignment you measure from the center of the wheel (hub), that way if there is any toe it is not factored in.

There are tons of youtube vids so be sure to watch them...

1) make 2 fixtures that will hold a string at the mid-height of your wheel (the hub). I use jack stands
2) with a tape measure place both fixtures the same distance from each hub. Also account for any difference in track from front to rear.
3) affix string and make tight. Remeasure to make sure nothing moved.
4) with a ruler measure the difference from the front of the tire to the rear of the tire at the mid-height. that is your toe.

 

It doesn't pointing the laser from the rear wheels to the front is used to determine the thrust angle of the rear axle. EG if the left wheel is pointing 100mm from the front wheel hub and the right rear wheel is 120mm
from the front wheel hub that means the rear thrust angle is not centered to the front axle and will push the rear to the right during acceleration. Once you get the rear thrust centered then you measure the total toe and adjust each side equal amounts to
get the total toe desired.

The front you do a similar measurement to the rear axle / hub so the steering wheel is centered when going straight.
I don't measure toe each side separate which is what you are thinking. I measure total toe after left vs right sides are centered.

So its 2 steps.

1 get the thrust angle correct.
2 then adjust for total toe.

With strings the assumption is you will get the strings centered correctly (center of the hubs) and measure from that point.
This process is very time consuming, and hopefully you don't bump them during adjustments and start all over again.

Starting over will mean you wont get the same placement time and time again. Using the lasers takes 5 minutes to take
all readings after adjustments and rears similar results time and time again (provided your suspension / steering is worn).

Remember the readings I take is the length of the tape measure back side of the wheels (b) vs the front side of the wheels. (a) This step is the total toe measurement.

The measurement from the rear hub is for thrust adjustment not measuring toe.

If you get a total difference front vs rear = 0 then you have 0 toe. If the difference in the rear measure bar is greater than
the front measurement then you have toe in, if the rear is less than the front you have toe out.

Think of creating / measuring a trapezoid.


Lets assume The Points D to A is the laser line of the front left wheel. And points C to B is the front right wheel.
so
step 1 is to get the angle of the line D - A = line C - B. This is where you use the rear axle hub as a reference point. (front adjustment)
If the lase line D-A is the same distance as the laser line C-B from the rear wheel hub and angles will be equal.

Then you measure the distance of line b (bottom) vs the distance of line a (top) again if distance a = b then you
have a perfect square = 0 toe.


In this example picture this would show that the wheel on the passenger side has more toe than the wheel on the driver side.
So you would adjust the passenger side until you get the same angle as the driver side. = 0 thrust angle (perfect)

Then you measure total toe. So if the total toe is too much, then you toe out BOTH Wheels the same amount of turns on the steering linkage and re-measure until you get the total toe required.

This is nothing more than geometry.

 

OK I analyzed the front suspension courtesy of a book written by Duntov. The toe in goes neg (in) as you drop the car. Duntovs supplied "bump steer" curve says this would be .17" of extra toe in from dropping the car 1.5"


Now I would not go strictly by that but it gives you an idea about how far off you are from before. That's about 3/16 inch.

• If you are only going to do this once or twice you do not need any fancy equipment at all. Hardware store stuff only. $10 maybe.
• You are correct on the caster; it should not change based on what you are doing. And this one you do not want to try and change without better equipment. If it was set well before, just don't mess it up. Do move the same number of A-Arm shims front & rear. If you mess it up you will notice it pulls right or left on the road a little. If it doesn't pull you're good. If it pulls you need a real alignment.
• Camber you can do with a bubble level. I still have my fancy bubble level. These days I just use a level app on my smart phone. Use some kind of straight edge that goes from wheel rim lip to lip. Around .5 to .7 neg is good.
• Toe-in you do last and you can measure the threads per inch and figure out how much of a tie-rod turn will get you close to 3/16" I would invest in two straight beams or levels from the hardware store. I use 4 foot square aluminum tubing. Times two. I just place them on the tire sidewall. It's good enough for toe. Just hit plain sidewall and not a white letter on one side only right? I use soup cans or coffee cans to raise the two beams up off the floor and above the sidewall bulge. Place the beams just touching the sidewall. Then place two retractable tape measures on each end of the beams going under the car, one in front and one in back of the tire, but spaced 4 feet apart. That is the part that makes this accurate. Pull the slack out of the tapes, I use the spring action of the tape measures to do this. Measure the difference and that's the toe-in. Divide by two since your beam is twice as big as the tire. I set my race car up to within 1/64" with this setup. I can set it up and measure toe in 5 min flat. (Eyeball the beams and make sure they both point to the same location on the rear tire, then you have the thrust angle set, or the the steering wheel centered. If you are just checking it, it doesn't matter.) The slow part is adjusting the toe. I can measure the toe-in faster than it took me to type this LOL!
• Parts list: Smartphone, level app, two 4 ft beams, 2 retractable tape measures, 4 coffee cans (how about beer cans??)

 

I would like to Thank you guys very much for taking the time to explain this a bit better for me. I think I'm starting to get my head around it thanks to your help.
below see photos of what I'm up against with the 4 foot level method. Which I think would work great on a pickup.

In this photo I think it's fairly clear that the fender sticks out past the tire. Making it difficult at best to have the level on the tire.

In this photo I'm trying to show how low my side skirts are. Once again making the measure the 2 straight edges method almost impossible.
.
.
So, this is what I came up with.
first I got a couple vinyl coated hooks, (free.)

Tieing a string to each one, I hook them inside the vent openings in each front fender.

Like this.
Now with jackstands placed approximately 6 feet in front of car and big sockets tied to end of strings for weight. I very carefully slide jackstands inward till string just touches the front edge of the tire.

So it looks like this. Now measuring the strings as close to the front of the car as possible, and then a second measurement just before the jackstands I can see if I'm toed in or out, in this case I'm still slightly toed out.
now of interest. Sighting strings from back of car.


Now I'm not certain how clear it is in these photos. But in real life it's pretty obvious that the right side is toed out and the left (Drivers) side looks pretty straight. Now I understand that I can't get a super accurate measurement of exactly how much toe I really have this way. But I'm just looking for a "touch" of toe in. Thinking I can achieve this.
thoughts?

 

After those photos were taken. Car back on the ramps and I adjusted right tie rod 1/4" turn longer and left tie rod 1/8" longer. Drove the car around. Steering has just a tad of play. (Steering box rebuild soon). And the wheel was perfect on one slide of the play if you know what I mean. Just a tad off counter clockwise in the center of the "Play".
set up my strings again making very certain to get them touching front of tires just right. (Used a bright light). Had the missus help with the measuring. (Like pulling teeth getting her into the garage). Dead straight. Zero toe in or out. Back on the ramps. Gave the right tie rod 1/8 turn longer. Drove it around the neighborhood. Set it up again. First measurement approximately 4 feet from wheel hub. Second measurement 6 feet from wheel hub. A fuzz under 1/16th inch toe in at these distances. Car feels good, wheel is straight. I'm calling it good.

 

Inventive!
I think I'll call it the 4 ft string method.
But the main thing is the numbers are good and it drives good!

 

Well, maybe the 6 foot string method. About 6 feet out from the wheel hubs. I have a small one car garage. So.... here's my custom camber guage.

Yup! Sawed off level. Fits the wheel just fine. But, it's been mentioned that a phone ap can be used to get precise degrees. Sounds interesting however, I'm an old guy. Not a "techno" guy. And don't even start with "It's just simple geometry ". I flunked geometry in High School and that's a long, long time ago. So, I have an android phone. I go to Google play store, that much I understand. What ap am I looking for??
Thanks again Guy's.

 

There are many iphone apps ( for Iphone guys ) that measure angles but the good ones allow you to calibrate the device from a level surface first.

One that does allow calibration is "iLevel"

I don't have a android device so sorry I can't help but I would search for the word angle finder,

Once you have the device calibrated then measure your floor so you can add or substract from what you measured.

This shows my floor is 0.1 degrees lower on the right side . So I add 0.1 to the reading for a tire on the right side and substract 0.1 from the reading on the left side.

Using you custom camber gauge and strings (as laser level) you can check the thrust angle (equal toe left vs right) In the diagram at the bottom where I show a red laser line make a string line parallel to you custom camber gauge mounted horizontal to the wheel and extend past the rear hubs. In my example side A reads 199 mm and side B reads 198 mm so the left wheel has more toe in than the right wheel. Or easier with a laser level mounted to your custom camber gauge. Same idea as what I use.



Here is a diagram to illustrate what you can do in your limited space garage.

See diagram below.

All you need is 4 pieces of a material of equal length (the longer the easier to get precise measurement) . Make them as long as you can but they need to be equal. Show as wood pieces in my diagram. Even if they where only 12" length. Place 2 tape measure across as shown at the end of the spacers. Note on the left side I moved the tape measures so each read = 230mm
It doesn't matter what reference point you use. Then measure the other side and note in the example the reading on the top tape measure is ~ 337 mm vs the bottom tape measure = 349mm which show the wheels are toed in.

Total difference = 349-337= 12 mm

Now you need math to determine what this means. But if the wood spacers = 24" and the tires are 255 60R 15 this is equal to 0.457 degrees toe in or 1/32".
So a table for this example
1mm difference = 0.0381 degrees = 1/32" actual = 0.5755/32 rounded up to 1/32
2mm difference = 0.0762 degrees = 1/32" actual = 1.1509/32 rounded down to 1/32
3mm difference = 0.1143 degrees = 2/32" actual = 1.7264/32 rounded up to 2/32
4mm difference = 0.1524 degrees = 2/32" actual = 2.3019/32 rounded down to 2/32
5mm difference = 0.1905 degrees = 3/32" actual = 2.8774/32 rounded up to 3/32

So my example shows the total toe is greater than 3/32" and actually calculate = 7/32" or ~ 1/4" which is a lot of toe in.

So align your car for a difference from 1-3 mm to get ~ 1/32" toe in.

But lets say your measuring bars are 4ft in length here are the results.

1mm difference = 0.0210 degrees = 0/32" actual = 0.3177/32 rounded down to 0/32
2mm difference = 0.0421 degrees = 1/32" actual = 0.6355/32 rounded up to 1/32
3mm difference = 0.0632 degrees = 1/32" actual = 0.9532/32 rounded up to 1/32
4mm difference = 0.0841 degrees = 1/32" actual = 1.2709/32 rounded down to 1/32
5mm difference = 0.1052 degrees = 2/32" actual = 1.5887/32 rounded up to 2/32

So now you could adjust in the range from 2-5mm difference to get ~ 1/32" just allows for more error in your measurements.

Now if they where 12" in length its not as easy to measure precise with a margin of error. Only 1 reading is ~ 1/32"

1mm difference = 0.0640 degrees = 1/32" actual = 0.9671/32 rounded up to 1/32
2mm difference = 0.1280 degrees = 2/32" actual = 1.9341/32 rounded up to 2/32
3mm difference = 0.1932 degrees = 3/32" actual = 2.9012/32 rounded up to 3/32
4mm difference = 0.2561 degrees = 4/32" actual = 3.8682/32 rounded up to 4/32
5mm difference = 0.1052 degrees = 5/32" actual = 4.8353/32 rounded up to 5/32

But any length from 2ft or longer do the setup to get from 1-3mm difference or if 4ft spacers 1-5mm difference will get the alignment very very close. Also remember the suspension parts will have a lot of play so anything in the 1-5 mm difference will work very well.

 

I use the "Clinometer" app on my android.

It's so accurate I use it to calibrate my bubble levels!

 

Thanks for that. I'll look into it. Just working on the rear camber now. And wouldn't ya know it. But one of my VB&P adjustable strut rods won't turn! Soaking in in penetrating oil now. Have a club run this coming weekend. Thought I'd run it and get it all settled in, then go back at it next week and tweak it.