DIY alignment

JamesShort · **Posted:** Fri Aug 19, 2011 11:39 am

Jason has hosted my app here:

http://cerient.net/alignment/index.html

The math proof for this method to work is here:

Pictures of my DIY camber gauge:

Ryan Holton · **Posted:** Fri Aug 19, 2011 2:51 pm

This would be awesome as an Iphone/IpodTouch app

JamesShort · **Posted:** Fri Aug 19, 2011 3:09 pm

I want to update it eventually to also give you numbers for each of the 8 wheel measurements for how much you need to change them to get to the intended alignment spec.

Right now you put in your numbers and it tells you what you have. If you have a bit of toe out on your RF, you play with the tie rod a bit, you take 2 new measurements, input them, and recalculate, so there is some guess and check involved.

Vincent Keene · **Posted:** Fri Aug 19, 2011 3:29 pm

Make an input for the thread pitch on the tie rod ends and have it calculate how many revolutions it will take to zero the toe.

JamesShort · **Posted:** Fri Aug 19, 2011 3:37 pm

Vincent Keene wrote:

Make an input for the thread pitch on the tie rod ends and have it calculate how many revolutions it will take to zero the toe.

Then you'd need another input for the distance of the center of the wheel that the tierod attaches to the steering knuckle

.

Ryan Holton · **Posted:** Fri Aug 19, 2011 3:46 pm

Vincent Keene wrote:

Make an input for the thread pitch on the tie rod ends and have it calculate how many revolutions it will take to zero the toe.

Ughhh, I always turn the damn tie rod the wrong way :stick:

JamesShort · **Posted:** Fri Aug 19, 2011 9:48 pm

Hmm, so I'm playing with the formula to determine what you need to change the 8 values to to get a desired toe for front and rear. In the front it should be fine (well sort of). With a car with 0 caster, if you adjust the toe via tie rods, the wheel rotates perfectly about a vertical axis that goes through the centerline of the wheel. Few cars have 0 caster but it will be close enough though.

In the rear for a car with eccentrics or a toe link, it's not a good assumption that the adjustment for toe makes the wheel rotate about the center of the wheel. It might rotate about a vertical axis that is in front or behind the center line of the wheel. It might just be better to do the guess and check method for the rear.

Donnie Barnes · **Posted:** Sat Aug 20, 2011 3:32 pm

Ryan Holton wrote:

Vincent Keene wrote:

Make an input for the thread pitch on the tie rod ends and have it calculate how many revolutions it will take to zero the toe.

Ughhh, I always turn the damn tie rod the wrong way :stick:

The iPhone version of the app should let you store a video showing which way does what.

--Donnie

Cash Davidson · **Posted:** Wed Feb 01, 2012 4:16 pm

I just HAD to "one-up" you, James by building a hands-free version. $14 worth of materials from HDR (Home Depot Racing)

Ryan Holton · **Posted:** Wed Feb 01, 2012 8:12 pm

Cash Davidson wrote:

I just HAD to "one-up" you, James by building a hands-free version. $14 worth of materials from HDR (Home Depot Racing)

Care to provide a materials list?

Cash Davidson · **Posted:** Wed Feb 01, 2012 9:05 pm

No Problem:

3' stick of 1/2"square tubing
Three 2" long 1/4x20 philips head screws
Three 1/4x20 nyloc nuts
Three 1/4" flat washers
Three 1" long, 1/4" dia aluminum spacers (or sleeves)

Cut the square tubing into a 10" piece and a 20" piece. Weld the long piece to the center of the short piece at right angles.

Drill 1/4" holes 3/4" from each end of the short piece. Assemble screw thru the spacer and square tubing and secure with a flat washer and lock nut.

Set the two lower stand-offs on the rim and mark the location for the upper hole. You can drill a hole for 18", 17", 16" rims and just move the stand-off.

The jig is held to the wheel with a 6" bungie. The digital level with magnetic base is from Sears - $30.

Enjoy!

Pete Guthrie · **Posted:** Sun Jun 29, 2014 8:25 pm

I have not read hte whole string yet, but do it old school.You setup a piece or two of wood..Nail them together in a shape, that on each end is a piece going forward, from the lateral part.and make them pivot from the top.Set it so that they are fairly tight against hte outer edges of the front tires.Then gauge toe from there, use a plumb bob to measure camber, not real clear on how to measure this..My father knows more about that then i do.a tape measure works for caster somewhat.

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