Need help interpreting alignment specs

[JD Cross]

I've just had an alignment done to 1993 specs at my dealership on my stock 91.

The final specs are:
Front
Camber left -.2 degrees, right -.4 degrees
Castor left 7.9 degrees, right 8.0 degrees
Toe left -.11 degrees, right -.14 degrees
Total toe .39 degrees
Steer ahead -.01 degrees

Rear
Camber left -1.5 degrees, right -1.6 degrees
Toe left .15 degrees, right . 20 degrees
Total toe .35 degrees
Thrust angle - .02 degrees

In the shop manual the toe is shown in mm not degrees.
Can anyone explain the mm compared to degrees on the toe numbers?

 

[SYRfabrication]

mm measurements are relative to the measuring surface, usually wheel diameter.

mm measurements can be converted to degree values through basic triangle trigonometry.
given you know what they considered the measurement diameter.

It is would probably be easier/more exact to just ask the people that did the alignment if their machine can display values in terms of mm as opposed to degrees.
This is a pretty common feature in most new aligning equipment, at least from my experience with hunter engineering equipment.

 

[warrenw]

See: http://www.nsxprime.com/forum/showt...ment-Toe-in-quot-mm-quot-vs-quot-degrees-quot

Below isn't my work. I am not that smart, well I am, but lazy overtakes smart...:smile:Converting wheel angle/degrees to mm


It is complex...

Step 1. Calculate the Radius (in mm) of the wheel and tyre together.

Formula (2 * tire width * aspect ratio / 100) + (wheel diameter) = wheel + tire diameter

Executing first equation:

Wheels are 15" and tires are 195/50R, so (2 * 195 * .5) + (15 * 25.4) =
195 + 381 = 576

576/2 = RADIUS = 288

Step 2. Calculate the angle each side wheel + tire: multiply the sin of 1 degree by the radius of the rim + tire, to give you the mm deviation from parallel with the centreline (CL)

Formula arcsin(radius) = radians per mm

Executing second equation:
sin(1) (degree) or sin(pi/180) (radian) = 0.017452

0.017452 X 288 = 5.026293mm

or to simplify: 6mm is about 1 degree, 1mm is 10 minutes of a degree

 

[JD Cross]

Warren
Thank you very much.
I did a search on this but didn't find any links.
The link you sent is a big help.

And many thanks for the math.
I'm work out the numbers for my 16" rear and check that against the degree reading I've got.

 

[JD Cross]

Further to my questions on this.

I stopped at Westside Acura in Edmonton and talked to Darren the shop manager.
He went to his Hunter wheel alignment machine and printed out the specs in the machine for an NSX as provided by Hunter.
Hunter shows the data in their machine for a 1991-2001 NSX and are all 93+ specs.
The data on the printout was shown in mm, degrees and fractions of an inch.

Why the service manager at Burrard Acura in Vancouver couldn't do the same printout so he could confirm the alignment he did was done to 93 + specs is still a question.