Originally Posted by shind3

Thanks for the earlier posts. Good info.


Let's talk about the tolerance stackup. Lots of things to consider here but let's start with the biggest contributor for most. Being able to measure to 1/32nds sounds impressive but it's not that great. Let's say everything is boxed up perfectly and you are measuring the leading and trailing edge of the wheel to within a range of 1/32" or +- 1/64". You are making 4 measurements per axle for toe and worst case scenario you could make all of them wrong by 1/64". That is 1/16" of total measurement error per axle. For a 17" wheel that results in about 0.20 degrees of total toe error using this trig calculator. I believe the factory says that total toe range is about 0.40 degrees so you've eaten up almost half of the entire range.

Obviously, the key to a good alignment is to reduce that per measurement error. Some people are good doing it consistently and looking for the diffused light through the fishing line as the lines on the scale underneath show up. I personally chose to use a Vernier caliper with a dial in inches. I took the same measurement multiple times and found I could generally get the values to within a range of 0.015". That is +- 0.075" times 4 = 0.03" of total measurement error per axle. That is total toe error of 0.10 degrees which is almost twice as good as using a ruler that reads to 1/32nds.

So the moral of this story, ditch the little ruler and use some Vernier calipers. Also, do a 'Gage R&R' on yourself and for your first time, take those same 8 measurements 10 times over. See what kind of measurement range you get. I was within 0.015".


The error in trackwidth between Rob's and Andrew's measurements by comparison is about 1/32" over 94.5" which only results in an error of 0.02 degrees.


Also there are other variables like wheel runout which can be quantified by a dial gauge which wouldn't be a bad idea to do.