Question about rear toe adjustment

[450knotOffice]

Hi guys,

I've attempted to measure my rear toe (total toe) three times now and each time I get a measurement that shows a little bit of toe OUT, as opposed to the required toe IN. The method I've used is to put a tack in the rear tires right in the center of the tread and at the most forward part of their rotation. I've dropped a plumb down and very carefully marked the position on my garage floor. I then rolled the car backward so the same tacks were now at the rear of the tires and dropped another plumb down and measured again. I then moved the car out of the way, found the marks on the floor and then very carefully measured the distance between the two forward marks and between the two rear marks. Each time I've done this, I've gotten a larger measurement spanning the front marks than between the back marks (about 1/4" more, which equates to about 1/16" on the rim), which seems to indicate that my rear tires are toed out, rather than in. I did a little geometry and came up with about 23 minutes of toe out.

I'm thinking of readjusting the toe eccentrics so to pull the toe back in slightly. In the past I outlined the springplates's positions on the trailing arms and marked the positions of the two adjusting eccentric bolts on each side.

The one thing I can't seem to find any info on is correlating how much I turn the eccentric with how much the toe changes, or to describe it a different way, how much forward I have to move the trailing arm relative to the springplate to get the toe to move in at least 20 minutes or about 1/16".

Any ideas? I don't want to just guess at it. I'd like to start out with a ballpark figure and then go from there with the fine tuning.

Thanks.

[Todd Simpson]

Scott-

I've been happy with the string alignment method. Check out this link.

alignment equipment pictures

This method will accurately give you your toe figures at each wheel. With a total toe measurement how you can be sure you're not crabbing down the road?

[450knotOffice]

You've got a point, Todd. Btw, during my searches I came up on a couple of your threads and found them to be quite informative.

Since you've done this, can you remember roughly how much twist corresponded to how much movement of toe?

[BertBeagle]

From your method you know the total but how do you know side to side?

[Todd Simpson]

I really can't...I also have a weltmeister sway bar and that uses a different eccentric.

Here's one thing that helps. Raise the car and measure the axle center to a fixed point like the torsion bar. Then as you make your adjustments you can be sure you've slid the axle forward for more toe in.

You could then correlate the distance the axle slid forward to the change in toe...a useful measurement for your next alignment.

I don't have slip plates for the wheels. I take all my measurements, write them down, then raise the car and make my adjustments. More toe on this wheel, less camber on that wheel. Lower it and measure again.

It's trial and error but each adjustment brings you closer.

[BertBeagle]

Originally Posted by Todd Simpson

I really can't...I also have a weltmeister sway bar and that uses a different eccentric.

If this is in answer to my question of how do you know side to side - I was directing that to 450knotofice who started the thread.

For you, do you set you strings first by measuring to the center of the hub (not the cover but to a machined surface on the hub)? That sets your string side to side so you get closer to parallel to the car center line.

[Todd Simpson]

No, that was for 450...I can't say "1/4 turn on the eccentric is 1/16 toe."

Yes, I measure to the stub axles. I take the wheel caps off and also remove the front dust covers. You just have to run around the car slightly moving the strings for about 10 minutes. You finally end up with the strings at an equal distance from each front wheel and an equal distance from each rear wheel.