I have been curious about the repeatability of alignment machine measurement and the need for periodic alignment work so I 'd like to share with you some of my records and experiment.

I had first alignment work done at 8600 miles (A)
Since then, I had been driving mostly in Austin city on smooth pavements and had participated in 2 days of track event (texas world speedway).
At 10,500 miles, I had the alignment checked (B).
Inital reading showed the caster and toes were out of spec.
So, they performed the alignment

 

In column E there should be a "-" in front of the toe settings, for toe in? That toe in setting might make the back end "lazy" with a fair amount of understeer. How has the car been taking turns?

 

The front toe spec is negative (-0.08

 

asin, a couple of comments.

Your toe specifications are likely in units of inches rather than degrees.

I agree with Prolene. The amount of rear toe in that you are now using may be on the high side. If rear tire wear has been a problem for you it may well be worse now. Also, your car may understeer more now.

By the way, I also had two realignments done within a two week period.

after first alignment:
front
camber -1.3d, -1.3d
caster 6.0d, 6.1d
toe -0.03", -0.03
rear
camber -1.3d, -1.3d
toe +0.08", +0.08"

before second alignment:
camber -1.3d, -1.3d
caster 5.8d, 6.0d
toe -0.05", -0.08"
rear
camber -1.3d, -1.3d
toe +0.09", +0.09"

The only significant change over the two week period was increased front toe out. Hoping for a better balance, I am now running more front negative camber, more front toe out and less rear toe in.

 

Mike,

The Hunter machine (my dealer used) translates everything into degree.
Your toes reading appear to be in degree as well.

The manual states the total rear toe spec is 6 +/- 2mm or 1/4" +/- 1/16".

RT has found the formula to translate that into degree in this link :
http://www.s2000online.com/forums/showthre...6065#post356065

 

I did have to have a discussion with my mechanic about torqueing all the adjustable components to spec. I know that they were not getting caster tight and I was getting it to move within days of the alignment. Since we had the talk I think I retain alignment better.

 

Assuming a tire diameter of 25":

At the front the factory per side allowed range of -1mm to +1mm corresponds to -0.09d to +0.09d or -0.04" to +0.04".

At the rear the factory per side allowed range of +2mm to +4mm corresponds to +0.18d to +0.36d or +0.08" to +0.16".

So I agree with you I was wrong in my post above. Your toes values are definitely in degrees. However, mine are definitely in inches. I quoted them directly off the Hunter printout which has them labeled in inches.

Also, my comment about your rear toe in is mistaken also. Assuming degrees it looks like you are using the factory setting.

 

cdelena, I agree torque is an issue. Access to the caster adjustment nut is very limited and a standard square drive socket torque wrench won't fit. You need use a special interchangeable head type wrench, like a Snap-On QC2I75.

 

[QUOTE]Originally posted by asin
[B]..................

RT has "found" the formula to translate that into degree in this link :

 

Yes.
I should have said you derived it

What is a snap-on QC-2175?
I want to tighten the caster nut myself before the $70 alignment setting is off.