Wheel alignment

[Last Indian]

Question, how many of you guys do your own wheel alignments? If so, what is your practice? I’ve always done my own, but most folks I know do not do their own.

[64 kiwi boni]

best i have done Last indian is a string line down the side of the car to at least get the wheels pointing the right way... then drive it to my mates tire shop and get him to Really set it..

 i justA had the little mk 1 cortina done and they where super happy with how it came out considering i had removed all the steering box system and replaced it with a rack and pinion and complete conversion to mk2 escort system with McPherson struts late model disc brakes and adjustable tca 

i even made the front sway bar adjustable , and lowered its front mounting points to help with anti -dive geometry 

 they also preformed a bump steer test and recorded all the results as i need it for when the car gets certified for the upgraded suspension  

this is 8 pages deep report just on bump steer, and as you can see it relates to ALL 4 wheels

Edited February 3, 2022 by 64 kiwi boni

[64 kiwi boni]

As i understand they move the suspension through its full travel and record the spec and incremented ride heights ...

 which in layman terms is going over a bump and the car moves up and down, and how the steering reacts to that suspension movement ... aka bump steer  

This is not justA toe in toe out but affects castor and camber too ... 

two lane black top would know all about this as he does a lot of race car cool stuff too make them go around corners really really good

Edited February 3, 2022 by 64 kiwi boni

[notallthere]

Two tape measures, a couple bricks and some angle iron.  Put them at the side of the and keep measuring until the front wheels are just pigeon toed by about 1/4" or less.  

[JUSTA6]

I've always laid a full length 2X4 up tight N square with the back tire/rim facing forward.  Gives you a reference to straight with the rear end.  Then tape measure for toe-in til =.  Plumb bob from top to center of rim gives you basic cam/castor. Then take it in for alignment.   If they have to do nothing,  my shop doesn't charge.  Clydes Frame in Pontiac (shameless plug)  Wouldn't trust anyone else.

[64 kiwi boni]

9 hours ago, JUSTA6 said:

I've always laid a full length 2X4 up tight N square with the back tire/rim facing forward.  Gives you a reference to straight with the rear end.  Then tape measure for toe-in til =.  Plumb bob from top to center of rim gives you basic cam/castor. Then take it in for alignment.   If they have to do nothing,  my shop doesn't charge.  Clydes Frame in Pontiac (shameless plug)  Wouldn't trust anyone else.

Yes justA 

having all 4 wheels pointing in the same direction is the very basic ... without the proper equipment you will never get the castor / camber right ... and then once you do have that set you have to redo your toe in / out 

THEN  you have to ensure you don’t have bump steer too ! 

[Last Indian]

There are lots of different ways to get to the same results! JustA case of what works for you. As I said I’ve done my own since I was 18, so I have change my approach more than once. Particularly when they moved to FWD & independent rear suspension. Whole different animal from beginning to end. 

Nothing is straighter than a string line & a good piece of ¼” x 1” steel bar stock! So for me I set the tires on some movable plates, not what you see in the pictures though, than put the steering wheel center straight, pull two string lines on both sides to see what the toe looks like with relationship of rear vs front. Than I start to look at camber. I drop a weighted sting line from the fender down past the lowest part of the rim, similar to what JustA said. With a machinist scale I measure the distance out from the top of the rim to the sting line and repeat for the bottom of the rim. The difference will give you the camber angle!

A few years back I found a company that sold a relatively inexpensive alignment kit. With it came two plates for checking toe, which used two tape measures as Notallthere & JustA do, which I always did as well, but these made it a little more convenient. It also came with a digital angle finder that you could use with one of the plates to find camber as well as caster. I didn’t care for this setup, but it did work great for me for doing camber angle my way. You can zero the gage. So with a straight piece of ¼” x 1” bar stock that is as long as the wheel diameter I do a setup that gives me the angle I want on a given wheel. By putting a given shim size under one end of the bar stock I get the angle I want. That shim measurement gives me the difference I need to see from the top of the rim to the string line to the bottom of the rim to string line. Works the same front or rear. After that I adjust toe. The line that runs front to back gives me a reference to square the rear tires to the front. Once that is done I do a final check for toe. So for example in the one pic that shows the parallel line and camber line. If I have negative toe both front and rear I pull the string taught, move the string in jut till I kisses the first edge of the back tire than the same again for the front. If the the toe is set right for both & the axles are squared to each other, the string will just touch the back edge of each tire with a gap at the front edge that will be equal to your toe for that side.

so in this case a .3125 shim over 18” equals 1.05 degrees in camber.

Edited February 6, 2022 by Last Indian

[Last Indian]

On 2/2/2022 at 11:42 PM, 64 kiwi boni said:

best i have done Last indian is a string line down the side of the car to at least get the wheels pointing the right way... then drive it to my mates tire shop and get him to Really set it..

 i justA had the little mk 1 cortina done and they where super happy with how it came out considering i had removed all the steering box system and replaced it with a rack and pinion and complete conversion to mk2 escort system with McPherson struts late model disc brakes and adjustable tca 

i even made the front sway bar adjustable , and lowered its front mounting points to help with anti -dive geometry 

 they also preformed a bump steer test and recorded all the results as i need it for when the car gets certified for the upgraded suspension  

this is 8 pages deep report just on bump steer, and as you can see it relates to ALL 4 wheels

Kiwi, bump steer!? That’s a tough one! I don’t know the MK1 very well. I know it only enough to say I would have to differ to someone else who knows it’s geometry. But, as a basic rule, not many of GM’s cars were given to bump steer! Ford on the other hand, whoa. When I meet my wife she had a 1970 Maverick. Which when we married we kept at first, talk about a piece of junk, sorry to any fans I offended, but among many of the issues I had with it, it was bump steer. Once while driving on the freeway at about 65 mph I hit a small pot hole I didn’t see. In one instance I was in the other lane 100%! A whole lane and never moved the wheel! 

Bump steer occurs normally only when either the geometry of the suspension is not designed right, as was the case with the Maverick. The suspension is altered, either through physical changing components in such a way that the proper geometry is lost or through modification of components that in turn loses such needed geometry. Also extreme wheel alignments can also cause bump steer, but that is actually pretty hard to do. 

[64 kiwi boni]

7 hours ago, Last Indian said:

Kiwi, bump steer!? That’s a tough one! I don’t know the MK1 very well. I know it only enough to say I would have to differ to someone else who knows it’s geometry. But, as a basic rule, not many of GM’s cars were given to bump steer! Ford on the other hand, whoa. When I meet my wife she had a 1970 Maverick. Which when we married we kept at first, talk about a piece of junk, sorry to any fans I offended, but among many of the issues I had with it, it was bump steer. Once while driving on the freeway at about 65 mph I hit a small pot hole I didn’t see. In one instance I was in the other lane 100%! A whole lane and never moved the wheel! 

Bump steer occurs normally only when either the geometry of the suspension is not designed right, as was the case with the Maverick. The suspension is altered, either through physical changing components in such a way that the proper geometry is lost or through modification of components that in turn loses such needed geometry. Also extreme wheel alignments can also cause bump steer, but that is actually pretty hard to do. 

when you talk about wheel alignment, its something that guys forget all about until they have finished their build and then try to drive their car... this really applies to situations where you change the suspension,,, ie, use aftermarket a arms/ dropped spindles etc.

as soon as you change anything in the geometry of your cars factory suspension ( like lowering your springs) you can alter the bump steer of that suspension... it can make a car extremely dangerous to drive... you can have the camber/caster correct, toe in/out correct but thats only at ride height. like you said Last indian with your wifes maverick .

move that suspension through its upper to lower movement alters the toe in/out... then you have a car that's all over the place !!

i am not very good at explaining, would you mind to explain Last Indian. 

i could draw a picture of what i mean but i am sure you could put that into words

Edited February 8, 2022 by 64 kiwi boni

[Last Indian]

17 hours ago, 64 kiwi boni said:

when you talk about wheel alignment, its something that guys forget all about until they have finished their build and then try to drive their car... this really applies to situations where you change the suspension,,, ie, use aftermarket a arms/ dropped spindles etc.

as soon as you change anything in the geometry of your cars factory suspension ( like lowering your springs) you can alter the bump steer of that suspension... it can make a car extremely dangerous to drive... you can have the camber/caster correct, toe in/out correct but thats only at ride height. like you said Last indian with your wifes maverick .

move that suspension through its upper to lower movement alters the toe in/out... then you have a car that's all over the place !!

i am not very good at explaining, would you mind to explain Last Indian. 

i could draw a picture of what i mean but i am sure you could put that into words

I can give it a go, but this is so involved that I will only touch upon basic segments. Then if there are questions I can do my best to answer them. 

The geometries of a suspension are critical! In handling as well as stability & safety. That simple statement is by far much more complex than the singularity of its appearance. 

Bump steer! In a nut shell! Positive toe on the load wheel! That’s it! But, what causes positive toe on a car that is set negative? That’s the very complexed question to discuss, because so many things effect suspension geometry!

The simple basics for determining bump steer is knowing the centerline of both upper & lower control arms with respect to the ball joint centerline intersecting the centerline of the Aarm shaft centerline. This imaginary line is carried towards the center of the cars horizontal midline. When this is done to both Aarms these two lines should intersect each other at some point. Next a line is drawn through the horizontal axis of the tie rod centerline. This line should intersect at the same point as the two Aarm’s intersect, for a zero bump steer.

While I’m at this point let me say that a good suspension setup not only strives for this, but if you draw a imaginary midline through the center of the car, (front to back) the point at which both intersecting lines, from both sides of all the Aarms & tie rods should intersect at the midline! Yet a near perfect setup will also find the intersection will occur not only at midline , but at or above CG! This is a truly balanced suspension.

To a degree this is why bigger sway bars are very advantageous! The more front nose dive in a corner the more likely a change in suspension geometry could cause toe to go positive.

Edited February 9, 2022 by Last Indian

[64 kiwi boni]

fantastic!! well done my friend 👍.. thats how i SEE it but its really hard to explain!! you have done good !! 

 i could add to your comment about sway bars that the mounting points also affect the anti dive aspect of your front suspension. 

 i learnt this with the cortina from a rally car guru... his name is Don fenwick, raced and engineered for possum bourne ( top nz rally driver) 

 and he lives here in Taupo... we have had many chats in his garage about geometry, and for a dumb plumber i learnt lots !!  

 

Edited February 9, 2022 by 64 kiwi boni

[Last Indian]

On 2/9/2022 at 12:06 AM, 64 kiwi boni said:

fantastic!! well done my friend 👍.. thats how i SEE it but its really hard to explain!! you have done good !! 

 i could add to your comment about sway bars that the mounting points also affect the anti dive aspect of your front suspension. 

 i learnt this with the cortina from a rally car guru... his name is Don fenwick, raced and engineered for possum bourne ( top nz rally driver) 

 and he lives here in Taupo... we have had many chats in his garage about geometry, and for a dumb plumber i learnt lots !!  

 

Kiwi, that is dead on! If you go back and look at the first page of my FWD ground pounder progression post you’ll see I address this. End link structure, type and placement all have a substantial impact on the performance of the sway bar itself, which ultimately translates to body roll/nose dive. No matter how big or good a sway bar is, if the end links won’t let the energy be transferred because they are to weak and deflect than the energy is lost. This also includes the bushings, their design and material selection.

[64 kiwi boni]

2 hours ago, Last Indian said:

If you go back and look at the first page of my FWD ground pounder progression post you’ll see I address this.

oh !! i will go have a read !! 

[Fitzy]

Dumb Question Time: I have replaced all my front end consumable parts plus a new steering box, etc so I KNOW my alignment is out. It was with much interest that I read the discussion on alignments at home. I thought I'd like to do a rough check on mine to see how out of whack it is. I collect a piece of straight bar to put behind the rear tyres and am ready to stringline the front wheels but the bodywork on old cars is outboard of the track. If I was going to stringline the centres of the wheels, there's no way it can be done with the protruding bodywork. 

I'm sure I'm missing an obvious point. It wouldn't be the first time! Would someone enlighten me as to how to string the centre of the front & rear wheels? Sure, I can string along the bottom but that's pretty rough. I suppose purely for toe in it's okay, but isn't toe in measured from the longitudinal centre of the wheel? A 'bush' method of measuring toe is by using 2 sticks and making a mark at the centre of the wheel at the back, then rolling the car forward and taking the same measurement when those marks have travelled 180°. I had a look at that too,  but the inner mudguards and other chassis structures prevent that method.

[Last Indian]

13 hours ago, Fitzy said:

Dumb Question Time: I have replaced all my front end consumable parts plus a new steering box, etc so I KNOW my alignment is out. It was with much interest that I read the discussion on alignments at home. I thought I'd like to do a rough check on mine to see how out of whack it is. I collect a piece of straight bar to put behind the rear tyres and am ready to stringline the front wheels but the bodywork on old cars is outboard of the track. If I was going to stringline the centres of the wheels, there's no way it can be done with the protruding bodywork. 

I'm sure I'm missing an obvious point. It wouldn't be the first time! Would someone enlighten me as to how to string the centre of the front & rear wheels? Sure, I can string along the bottom but that's pretty rough. I suppose purely for toe in it's okay, but isn't toe in measured from the longitudinal centre of the wheel? A 'bush' method of measuring toe is by using 2 sticks and making a mark at the centre of the wheel at the back, then rolling the car forward and taking the same measurement when those marks have travelled 180°. I had a look at that too,  but the inner mudguards and other chassis structures prevent that method.

Actually Fitzy midline of the tire is not where you should measure for toe! Because camber has the largest impact on static toe, about 1” to 2”s off the ground is the typical point to measure. Since camber is an angle that accentuates with distance from the point of origin, that is where you measure. For instance, say you move the tie rod to see a millimeter.0397 of negative toe at tire centerline. If you now drop down to 1” off the ground the measurement, depending on camber angle could be far larger! And that point is near the tire tread so that is actually where the wear of the tire tread occurs. 

If all you wish to do is check that the rear tires are square to the front & check for a ballpark toe at the front. Do this take your jack stands or something similar and tie a string line longer than the wheel base. Move the jacks in towards the car, both front and back, but keep the sting taught. Do this until you get close to both tires. Than move back jack until the string touches the back edge of the back tire first. Now start to move the front jack until it touches an edge of the front tire. Now go to the back tire, pull the jack out so the string moves completely away from the tire, than move it back slowly till it touches the tire. If the back axle is square to the car the string should touch the front & back edge of the back tire. When you do this do it slow & watch carefully that string touch both edges at the same time. You can tell this by blowing on the string or lightly touching it, as when it contacts the tire you’ll see it doesn’t move freely. 
Now leave that jack where it is and go to the front and do the same thing! Unless you have zero toe you will see the string touch either the front or back edge of the front tire first. Now do the same thing for the other side.

[Fitzy]

Thanks Last Indian. I always read that measuring toe from the longitudinal centre of the wheel was the way to go, but as you point out, where the tyre contacts the road should be the parameter. I've run out of time today and have other stuff to do tomorrow. Car will be going in for a professional alignment soon anyway. Thanks for the advice and methodology - always appreciated.