Help with Alignment Specs?

[ylostrk]

Just got the shop manual for my 2002 Z06. I'm looking on page 3-20 at the alignment specs. Sadly, they don't put units on any of the measurements, so I'm wondering whether the toe is expressed in inches or degrees. Or maybe something ELSE. Looks like degrees, but that makes the toe so close to zero as to be barely measurable.

I've been advised by another autocrosser to use 1/4" toe-in at the back and zero at the front, but that seems WAY far away from the specs in the rear. I'm more surprised at the specs than at my friend's numbers, but I want to understand the situation before I go cranking.

Thanks for any help...

jim

[IT L GO]

Alignment measurements are in degrees


Front Alignment Specs Service Allowable Service Preferred
Front Individual Toe +0.14 to -0.06 degrees +0.04 degrees
Front Sum Toe +0.28 to -0.12 degrees +0.08 degrees
Front Individual Camber +0.50 to -0.70 degrees -0.20 degrees
Front Cross Camber +/- 0.25 degrees within 0.50 degrees
Front Individual Caster +6.4 to +7.4 degrees 6.9 degrees
Front Cross Caster +/- 0.25 degrees within 0.50 degrees
Steering Wheel Angle +1.0 to -1.0 degrees 0.00 degrees

Rear Alignment Specs Service Allowable Service Preferred
Rear Individual Toe +0.09 to -0.11 degrees -0.01 degrees
Rear Sum Toe +0.18 to -0.22 degrees -0.02 degrees
Rear Thrust Angle +0.10 to - 0.10 degrees 0.00 degrees
Rear Individual Camber +0.32 to -0.68 degrees -0.18 degrees
Rear Cross Camber -- within 0.50 degrees

-or-

Front Individual Toe: +0.04 degree +/- 0.10 degree
Front Sum Toe: +0.08 degree +/- 0.20 degree
Front Individual Caster: +6.9 degree +/- 0.50 degree
Front Cross Caster: within +/- 0.25 degree
Front Individual Camber: -0.70 degree +/-0.50 degree
Front Cross Camber: within +/-0.25 degree
Rear Individual Toe: -0.01 degree +/- 0.10 degree
Rear Sum Toe: -0.02 degree +/- 0.20 degree
Rear Individual Camber: -0.68 degree +/- 0.50 degree
Rear Cross Camber: within +/- 0.50 degree

[DJWorm]

At the track, with portable Laser tools F/R Camber & Front Castor is usually measured in degrees or by a conversion of a dial indicator; and on a shop set up machine it is usually given in degrees as well.

Like wise the F/R Toe adjustments are usually measured in degrees or fractions of an inch in the shop.

However at the track most devices and the tried and true "string method" and most modern Toe gauges that use a tape measure (obviously are) are calibrated in fractions of an inch or converted to fractions of an inch from a dial indicator in the case of most popular Laser Toe gauges or laser Toe plates.

Personally, that is why I quote Toe settings in fractions of inch.

[ylostrk]

I prefer inches for toe as well, but they're not properly specific, depending on tire diameter. Angles are harder to deal with mathematically, but a degree is a degree anywhere.

For any single car, I usually end up with a table in decimal inches, based on the wheel lip diameter (rather than tire size). Then, using strings either horizontal or vertical, I just measure the difference between the distance to each wheel lip. I like it that way because I can get repeatable measurements down to the nearest 10 thousandths, where the tire surface wobbles around too much.

jim

[Dennis wilson]

After lowering my car cutting 2/3 off front bushings the top of the wheel is approx. 3/8 in. in from the bottom Does this seem like too much neg. camber? The car tracks straight and true. Thanks very much.