alignment questions

[egchewy79]

I also posted this on the other forum:

Camber, Caster, Toe
working on alignment today. received my Tenhulzen 2 wheel alignment tool the other day and assembled per directions. Solid axle w/ manual steering rack.
Camber first, -0.5*. Caster 3*. Toe in 1/16" total

I found that I had to readjust camber again after caster done.
I tried using the alignment plates when measuring toe, but I abandoned this and went to the string method instead.
With the alignment plates measuring toe, I get the total toe, but no idea if one wheel is directly straight and the other is toed in 1/16", or if one wheel is toed out 1/16" and the other in 1/8" for a total of 1/16" toe in.
ran a string from the back to the front. since I have offset wheels, the rears are going to touch the string before the fronts. I moved the string until the string was touching the back of the rear wheel and stopped once it barely touched the front of the wheel. I then measured the distance from the string to the rear and front of the front wheel. I first make the distances equal on the front and rear edges of the wheel, then make the front toe in 1/32" to get total toe 1/16" in.

a few questions
I noticed that my DS is set further in from the string than the PS, by about a total of just under 1". At first, I thought maybe my rear axle needed adjusted w/ the lower 3 link adjustment bar. I measured from the shock tower to the outside of the wheel on both sides and it's even.
Then I thought it might be my steering rack that was off center, but the more I thought about this, it doesn't make sense since the rack only connects to the wheel via the tie rods, which control toe. I also used the breeze offset bushings and pretty meticulously got the rack centered using Karlos' write up from this forum.
Does anyone else have any ideas how to better center the front wheels? is the frame offset for some reason that I haven't read about?
also, when measuring toe, should the measurement be from a center line defined by the string or relative to the rear of the wheel? and where on the wheel should I be measuring? at the very end of the sidewall, the middle portion of the sidewall, or the rim? it makes a difference where on the wheel I take the measurement, esp if i'm only toeing in 1/32" on each side.

[CraigS]

"I noticed that my DS is set further in from the string than the PS". Your driver side what?
"Does anyone else have any ideas how to better center the front wheels?" In relation to the body?
- I don't remember how far along you are on body fitting, but the body should be fairly well centered on the frame measuring fender flare lip to shock top bolt. It may not be centered hood opening to the 3/4x3/4 steel tube under the edge of the hood. The left/right of the body is controlled by the quick jack mounts. If you remember back to a bare frame those mounts are fine for their purpose but you can imagine if someone grabbed one to pull the frame around it would easily bend sideways. It is very common to need to tweak those mounts.
Moving on to your other Qs. When starting from scratch I like to get the rack centered which you have done. But just to clarify, turn the rack full left and then count wheel turns as you move it to full right. Now move it back to center by counting half of those turns. Then as I am making adjustments I look at how many threads are exposed beyond the jam nut on the tie rods so the overall left and right tie rod length will be close to even. Don't forget to also look at the steering wheel so it is straight. If it's off you can fudge a little on the tie rods but may need to move the splines on the steering column to rack adapter which usually means removing the rack mount bolts.
- To check if your toe in is equal on both sides I squat in front of the front tire and sight along the outside edge of the front tire toward the rear tire. Usually you will see maybe 1 inch of the rear tire tread visible. Whatever that dimension is, it should be the same left and right.
- I measure toe at about the center of the tire vertically, about 13 inches from the floor. I measure to the outside of the widest part of the tire sidewall. Measuring to the rim would generally be slightly more accurate but my tool can't measure to the rim at the rear of the tire and then be moved to the front. Naturally I am careful to not measure on a raised logo part of the sidewall.
- Yes adjusting caster affects camber and vice versa. I do both at the same time making guesses how much to turn the UCA sleeves. I call it going around in circles that keep getting smaller as you get closer to your desired specs. As you get close to where you want the specs to be gently tighten the jam nuts after each adjustment. If you leave them loose, think it's perfect, and then tighten them, you will be off a little. The sleeves get just slightly longer when the nuts are tightened.
- BTW, I have done this dozens of times over the years and even so, a full on start from scratch alignment, is a 3-5 hour process. Be glad you have a solid axle because the IRS mostly doubles the time needed. I am glad to see you are doing this on your own. You can imagine how it would go at a standard alignment shop.

[rich grsc]

And you wonder why I take mine to a local shop and give them a $100 for an alignment.

[edwardb]

First, the front end is not offset to one side. Intentionally or otherwise. I doubt very much that it is. And you're right, the steering rack setup (centering, etc.) wouldn't have anything to do with overall centering of the suspension. Hopefully you're taking into account that the rear track is about 2 inches wider than the front. That's what my solid axle builds have been. I also think you'd get better and more repeatable results using the alignment tool you have for setting the toe. I have dedicated toe plates (Heidts TA-003) which work similarly to yours with the tape measures. Rested firmly on the ground and against the properly inflated tires, seem to give accurate results.

Having said that I agree your front to back track needs to be correct. Using strings parallel to the frame rails would be a way to check and confirm. I use a magnetic base laser level (Bosch GPL3T) stuck to the toe plates and pointed at the rear tires. I confirm that with the toe set the laser dot hits the rear tires at the same point on each side. Typically 1/2 - 3/4" or so from the outside. Same idea as using strings but quicker and easier. If the rear suspension is centered, then checking in this way confirms the front track and toe is also centered.

I do all my own alignments and have helped with several other builds as well. Kind of an interesting and rewarding process if you're into that kind of thing. If you can build your own car you should be able to set the alignment. With the right equipment it works well and at least in my experience better than taking it to a shop that may/may not have any idea what they're doing. Plus in my area 1-2 visits is going to equal the price of the tools needed. But I agree it's a multiple hour process especially the first time. Which is why I always do the initial alignment with the body off. Everything is way easier to reach. Then check and touch up as needed when done.

[Jeff Kleiner]

This is a copy of the response I posted in the other forum:

I use toe plates and measure referencing at the outer diameter of the tire tread. Look at it this way; if you measure the rim and set it for let's say 1/16" with a 25" diameter tire then mount a 30" tire the difference at the tread will be much different. OR---to go the other way, if you measure 1/16" using a 15" rim with 25" diameter tire and then install an 18" rim with a 25" tire the toe will measure differently at the rim even though you made no changes to the tie rods and the toe at the tires will be the same. In that case which of the measurements you came up with is correct? The one with the smaller diameter rim or the one with the larger? It's for this reason that I use the tire O.D. when measuring in inches and why modern alignment equipment references in degrees (1 degree is 1 degree no matter what the tire and rim combination).

That should be clear as mud just like discussing pinion angle :p


Jeff

[GWL]

Based on your question, I decide to do a write up of my process. Something I wanted to document, I just needed the push to get it done.

I just posted my journey here: https://thefactoryfiveforum.com/showthread.php?37549-My-Roadster-Alignment-Journey

George

[walt mckenna]

And you wonder why I take mine to a local shop and give them a $100 for an alignment.

Some things you just leave to others who have the right tools plus you get this nice summary sheet with all the data documented.

[egchewy79]

"I noticed that my DS is set further in from the string than the PS". Your driver side what?
"Does anyone else have any ideas how to better center the front wheels?" In relation to the body?
- I don't remember how far along you are on body fitting, but the body should be fairly well centered on the frame measuring fender flare lip to shock top bolt. It may not be centered hood opening to the 3/4x3/4 steel tube under the edge of the hood. The left/right of the body is controlled by the quick jack mounts. If you remember back to a bare frame those mounts are fine for their purpose but you can imagine if someone grabbed one to pull the frame around it would easily bend sideways. It is very common to need to tweak those mounts.
Moving on to your other Qs. When starting from scratch I like to get the rack centered which you have done. But just to clarify, turn the rack full left and then count wheel turns as you move it to full right. Now move it back to center by counting half of those turns. Then as I am making adjustments I look at how many threads are exposed beyond the jam nut on the tie rods so the overall left and right tie rod length will be close to even. Don't forget to also look at the steering wheel so it is straight. If it's off you can fudge a little on the tie rods but may need to move the splines on the steering column to rack adapter which usually means removing the rack mount bolts.
- To check if your toe in is equal on both sides I squat in front of the front tire and sight along the outside edge of the front tire toward the rear tire. Usually you will see maybe 1 inch of the rear tire tread visible. Whatever that dimension is, it should be the same left and right.
- I measure toe at about the center of the tire vertically, about 13 inches from the floor. I measure to the outside of the widest part of the tire sidewall. Measuring to the rim would generally be slightly more accurate but my tool can't measure to the rim at the rear of the tire and then be moved to the front. Naturally I am careful to not measure on a raised logo part of the sidewall.
- Yes adjusting caster affects camber and vice versa. I do both at the same time making guesses how much to turn the UCA sleeves. I call it going around in circles that keep getting smaller as you get closer to your desired specs. As you get close to where you want the specs to be gently tighten the jam nuts after each adjustment. If you leave them loose, think it's perfect, and then tighten them, you will be off a little. The sleeves get just slightly longer when the nuts are tightened.
- BTW, I have done this dozens of times over the years and even so, a full on start from scratch alignment, is a 3-5 hour process. Be glad you have a solid axle because the IRS mostly doubles the time needed. I am glad to see you are doing this on your own. You can imagine how it would go at a standard alignment shop.

I guess the first part of my question regards how to center the rear end using the panhard bar. I have measured the distance from the shock tower to the outer part of my rear tires (offset, 315 in the rears) and it's equal on both sides. However, when using a string method to check toe on my front tires, the DS is further away from the string by about 1" than the PS. I understand that with my offset tires, the fronts will be narrower and not touching the string that is set parallel to the rear tire. I have been trying to run the string in the center of the tire. it seems that the front suspension should be fairly limited in right/left movement, and I should be moving my panhard bar to bring the DS rear wheel about 1/2" out.

I figured I've come this far, why not learn about alignment on the car too, right?!
I used the rough distances recommended in the build manual for the UCA but this was for power steering. Both castor angles were around 6* with a -1* camber angle prior to adjusting. I actually felt like the car handled pretty well. It was bit hard to turn the wheel at a stop w/ the manual rack, but otherwise was quite happy with the initial handling. we'll see if it's better after I decrease the castor to 3*

[Big Blocker]

What Jeff said in post #5 . . . toe-in/out measurements are dependent on the tire diameter and should always be done with the tires that are going to be used as "installed equipment". Doing an alignment with "roll-around" tires and then mounting something different is going to throw off your toe-in/out settings. Tires MUST be pointed straight ahead, steering rack centered in its "lock-to-lock" position. Any offset toward either side for turning will introduce steering angles and throw off your measurements as the tires pivot at different angles during a turn, changing toe-in/out on turns . . .

Unless you own an [electronic] alignment shop or a highly sophisticated laser guided alignment rack, toe plates are the best way to ensure accurate [repeatable] measurements.

Doc

[egchewy79]

ok. posted this on the other forum as well. don't feel the need to double dip and reply if you're on both.
I had fully lengthened my panhard bar to try to move the rear axle towards the PS to even out my strings running from rear to front. with the panhard bar fully extended (about 1" of thread showing on the ends) I had just under 2" of distance between my string and my front tire and under 1" on the PS.
some on the other forum had suggested shortening the panhard bar to make up for the discrepancy between my string line between by DS and PS strings.

i tried shortening my pan hard bar all the way to see what effect it had. as I suspected, it made the distance on the DS larger and the PS smaller, so now the DS distance to the string is over 2" and on the PS it's under 1/2".
this led me to take a look at my front wheels, thinking that maybe they weren't centered to the frame.
measuring from a set point on the shock mount on either side, I found interestingly that the outside of the DS wheel was actually about 1/4" further out from the frame than the PS wheel.
I double checked my front UCA and LCAs to make sure I didn't inadvertently attach them to the wrong places. And by correcting the discrepancy in the distances of the front wheels, I would actually make the alignment measurements of the rear axle worse.
Any other thoughts here?

[edwardb]

...this led me to take a look at my front wheels, thinking that maybe they weren't centered to the frame. Measuring from a set point on the shock mount on either side, I found interestingly that the outside of the DS wheel was actually about 1/4" further out from the frame than the PS wheel. I double checked my front UCA and LCAs to make sure I didn't inadvertently attach them to the wrong places. And by correcting the discrepancy in the distances of the front wheels, I would actually make the alignment measurements of the rear axle worse. Any other thoughts here?

Don't know where your measuring from on the front wheels. But until your alignment is finished, any measurements to the front wheels would be suspect. Wouldn't take much camber or toe difference from side-to-side to make a 1/4" difference. Unless you have something assembled incorrectly, which sounds like you've checked, I don't think you're going to find the front suspension off center.

[egchewy79]

Don't know where your measuring from on the front wheels. But until your alignment is finished, any measurements to the front wheels would be suspect. Wouldn't take much camber or toe difference from side-to-side to make a 1/4" difference. Unless you have something assembled incorrectly, which sounds like you've checked, I don't think you're going to find the front suspension off center.

I'll double check DS camber to make sure it's negative and not positive. This would definitely explain the difference. I was measuring to the spot on the frame between the shock mounting tabs. I'll double check my strings to make sure they're parallel to the frame rails and each other.

[egchewy79]

Do I need to be rolling the chassis back and forth after making changes to the panhard to allow things to settle in? Not quite sure my next step

[Rdone585]

Adjusting the panhard bar would not necessitate rolling the chassis. However, lifting the car does. Since the front suspension has drooped when you raised the car off the ground you will need to roll the chassis back and forth a little to get it settled. This is mostly due to the rubber bushings in the lower control arm (from what I've been told). On an alignment rack the technician can't roll the car so they will usually use my swaybar and do pullups with it. The turn plates on the alignment rack then allow the wheels and suspension to settle.

[CraigS]

I will stick to this forum. Center the rear axle as you had it before. Equally distant from the shock mounts. Now you are done w/ the rear. Just so you know, on all cars the rear is done first so the thrust line is centered. Imagine looking down from over the car, the rear axle is the top of a letter 'T'. It needs to be centered and it needs to be 'aimed' straight forward toward the exact center of the car. The vertical part of the "T" is the imaginary thrust line. Since your rear lower control arms are a fixed length (you didn't use adjustable LCAs did you?) we assume the thrust line is fine.
https://live.staticflickr.com/65535/50460127426_8b4a7397ce_w.jpg (https://flic.kr/p/2jSZkT1)top view (https://flic.kr/p/2jSZkT1) by craig stuard (https://www.flickr.com/photos/152454123@N04/), on Flickr
This pic isn't perfectly centered but I think you will get the idea. I don't use the string method because it is too hard to find places to measure to on an FFR. And every time you jack up the front to adjust, you have to redo the strings.

[rich grsc]

Like I said on the other forum, stop messing with the pan hard bar​. As Craig just posted, center the rear, then leave it alone.

[GTBradley]

And you wonder why I take mine to a local shop and give them a $100 for an alignment.
I can’t even get past what PS means - Passenger Side or Power Steering...and what if it’s a righthand drive, then what?:confused:

[rich grsc]

PS, post script

[egchewy79]

I can’t even get past what PS means - Passenger Side or Power Steering...and what if it’s a righthand drive, then what?:confused:

DS=driver side
PS=passenger side
I guess these designations would still hold up for RHD cars. Does FF sell RHD cars in the US? I know that there are some Aussies floating around on these forums that have RHD roadsters.
They actually sent me a RHD dash w/ my kit that they had to replace, so I'm guessing that it's an option.

[CraigS]

I am just glad you are using PS and DS. I worked for several decades as an auto tech and the number of time we had a problem because a customer had said right or left but they looked at it differently was staggering. Nearly every time we would get a new service advisor we had to train him/her that there is NO left or right, only driver and passenger sides.

[egchewy79]

OK. finally dialed in my camber and caster after 2 hrs of monkeying with it. it's amazing how much the lock nuts will pull your camber out of spec. I found that I had to set my camber to -0.7* before tightening the lock nuts to get it at -0.5*. caster is set at 3.5*.
now for toe. I was trying to use the string method to align my front wheels. I was stretching a string on a jack stand from behind the rear wheel, moving it in just until the string was touching the back and the front of the rear tire. while doing this, I found that my DS wheel was further away from the string than my PS wheel. I assumed that I had to move my rear axle towards the PS but ran of threads on my panhard to do this. I currently have my rear axle centered measuring from the shock tower tab to a consistent spot on each tire.
I finally figured out that my strings are not parallel to my frame. this means that my rear axle is off by a few degrees, leading to the appearance that my front DS tire was too far from the string. In other words, my rear axle is not perfectly square with the thrust line. I realize there's nothing I can do about this without adjustable lower arms for the rear axle.
I'll reposition the strings so they're parallel with the 4" frame tubes and proceed from here going forward.136339

[GWL]

I think that trying to skim the rear wheel/tires, in two places, is too much of an error maker. Just a tiny bit off in the back trying to touch each part of the rear tire will make a large difference in the front. In addition, how can you trust the side walls of the tire to be perfect. 1/32" at the front is very small, half the thickness of my string.

Square the strings to the frame. I think a jig like I suggested made it way easier to set up. Note, that one end of the jig sits low to hit the frame while the outside part, where the string will touch, allows you to hold the string higher toward the center of the tire where you need to measure. In the last picture below, the string is lower because while I'm taking my measurement at the outside diameter of the tire I'm actually measuring to the rim using my aluminum jigs, which is dead on. You without the aluminum jig could measure to a spot on outside diameter of the tire. The string method will also allow you to check the rear end squareness, once set up for the front.

Basic wood jig to set up strings, you need at least two of these.
https://live.staticflickr.com/65535/50449975288_0f02bb108d_z.jpg (https://flic.kr/p/2jS6j19)IMG_9278 (https://flic.kr/p/2jS6j19) by George Ligon (https://www.flickr.com/photos/161275344@N04/), on Flickr

Set up measuring tow-in at both the front and rear wheels.
https://live.staticflickr.com/65535/50450672706_0acec50e3c_z.jpg (https://flic.kr/p/2jS9TjA)IMG_9319 (https://flic.kr/p/2jS9TjA) by George Ligon (https://www.flickr.com/photos/161275344@N04/), on Flickr

George

[GWL]

Ok, I just noticed your picture.

This is what I'd do.

Set up strings, parallel to the frame, a bit further away from the tires, then you can measure to the toe plates, and double check front to front toe-in at the end with the toe plates.

Using the strings will allow you to first get the wheels parallel to the frame then add toe-in at 1/32" on each side, which is probably half the string thickness. Remember, when it moves at the front of the tire it also moves at the rear, so now you are looking at a 1/64" movement.

As, I'm thinking about this it wouldn't be a perfect 1/64" because of the caster you have set. Just be aware of the front and rear of the tire measurement with the strings.

George

[egchewy79]

thanks all
is the bottom of the door frame parallel with the 4" frame tubes?
just thinking out loud, but it might be easier to measure to these as the 4" tube is round and there are brake/fuel lines running along them that would make it difficult to get accurate/consistent measurements. I do like the idea of making a wood jig and cut out reliefs for the lines.

[nuhale]

When I did my "rough" alignment I used metal carpenters squares clamped together. A cheap alternative if you have harbor freight near ya. The clamps we're positioned to give it upright support. Used 2 different sizes as I measured from the inside of the 4" rails to a string pulled between two jack stands. Went from the inside of the 4" rail due to interference from brake & fuel lines. Although I did this as a "rough" to get it over to the alignment shop they informed that I was pretty darn close on toe and rear track width with this method (didn't focus on camber and caster other than eyeball).

I know there are many folks that want to do this themselves but my experience with the alignment shop was great. Not a bad $90 spent in IMO. Just some more piece of mind with it being "dead nuts" in camber caster and toe.

[CraigS]

I think that trying to skim the rear wheel/tires, in two places, is too much of an error maker. Just a tiny bit off in the back trying to touch each part of the rear tire will make a large difference in the front. In addition, how can you trust the side walls of the tire to be perfect. 1/32" at the front is very small, half the thickness of my string. ...

I agree. One more reason I don't care for the string method. I must have put this next picture in another thread but this is how I do rear toe/thrust line.
https://live.staticflickr.com/1750/42669853081_ed36d72996_z.jpg (https://flic.kr/p/281A9J6)IMG_20170419_160647869 (https://flic.kr/p/281A9J6) by craig stuard (https://www.flickr.com/photos/152454123@N04/), on Flickr
You can see the laser dot at the top of the white scale near the front tire. That scale measures from the inside of the 4 in tube because I had a brake line on the outside and there is a duplicate on the other side so I can use it on both sides of the car.
https://live.staticflickr.com/871/41458729111_5b428592af_z.jpg (https://flic.kr/p/26ayPLk)IMG_20170419_160800746 (https://flic.kr/p/26ayPLk) by craig stuard (https://www.flickr.com/photos/152454123@N04/), on Flickr
I have adopted this technique recently. Previously I used an 8 ft piece of wood interior trim that I kept checking that it was still straight. I pushed it against the outside or the rear tire at about 13 inches off the floor, set it on some blocks to maintain the height and went forward to measure to the frame tube. The laser is much better.

[egchewy79]

OK. took ideas of GWL and CraigS and made a love child of the two. I made some wood jigs that would measure to the inside of the 4" rails to avoid fuel/brake lines on the outside of the tubes. the only thing I had to avoid was my battery cables that run on the inside of the PS tube. string was then run to outside of the jig to set my toe. Front wheels are pretty much even distances from the string. my rear axle is off center, ie not square to the thrust line, which made my previous "skimming the rear wheel" technique inaccurate, leading to over a 1" off between the DS and PS front wheels.
once i got my wheels parallel to the string, adjusted both inner tie rods equal amt of turns to get total toe in 1/16"
thanks for all the help.136488136488136489

[GWL]

Realize that camber and caster must be done before toe-in. I guess you are going to have someone else set up alignment so you got toe-in close to drive it.

Camber is somewhat easy to get 'close' while caster is another game altogether. Camber can be done with a digital level set against the tire to get it somewhat close.

Also note that you have to work back and forth with camber then caster then back to camber again. You keep at it until you get both of the them dialed in. I had to figure that concept out myself as I went back to check camber and found it out of specification. You set both camber and caster with the two adjustable upper control arms and if you change one setting it changes the other.

Edit: I had forgotten you had already done camber and caster.

George

[egchewy79]

I already did camber and caster prior to toe.
-0.5 camber, 3.5 caster
Found out that I had to overshoot camber as it changes once you tighten down the lock nuts.

[edwardb]

I already did camber and caster prior to toe.
-0.5 camber, 3.5 caster
Found out that I had to overshoot camber as it changes once you tighten down the lock nuts.

I would suggest you're loosening them too much. They need to be just loose enough to allow movement so the suspension doesn't bind up when adjusting and give inaccurate measurements. But not so much they're flopping around or move again when tightened. I would estimate maybe only 1/4 - 1/2 turn on the lock nut.