DIY wheel alignment gauge [modular design]

DIY wheel alignment gauge (modular design)

There are many products in the market for wheel alignment. However, I have not found the one I want to own and use. Decent ones are a little pricey for a hobby mechanic, on the other hand, budget ones are not really fulfilling my expectation. So, I ended up to design my own. With this design, you can build up your own wheel alignment gauge in several styles, whatever size, for your needs or preference!

General structure/Design
This DIY wheel alignment gauge consists of a number of 3d printed parts, 20mm x 20mm aluminum extrusion square tubes, and some hardware such as bolts and nuts. Because of the module design, you can create your own gauge in any size, in several different ways. In the pictures, I’m showing several example setups that I can imagine, as well as illustration and parts list of each module (sub-assemblies).

The components other than the 3d print parts, aluminum tubes and hardware are probably available at a local DIY store or online shops. All you need to do is cut some tube down for your desired length, 3d print, then assemble them. No complicated fabrication involved.
The accuracy of the gauge is not really dependent on those 3d printed parts itself. I designed the wheel attachment to be adjustable, to compensate some tolerance of 3d printed parts, in order to keep the gauge in parallel to the wheel.

I'll continue to add more information such as print/assembly instruction time by time. In the meantime, If you have questions, please contact me in comment or Instagram for a private chat.

Wheel attachment
It’s very important that the wheel rim attachment fits to your car.
You can download Wheel rim attachment files for free. I would recommend to check them before purchase/download this gauge.
There are 2 types of attachments. The standard type is fully 3d print parts (with some hardware). Another one is Sheet metal type, which is 3d print part + t=0.5mm sheet metal part hybrid. I design this version to minimize the thickness of the attachment, for the cases that the clearance between tire and wheel rim is not enough.
(The standard type may be tight for some tires size or brand, or those "meaty" set up)

Camber measurement
Camber measurement is pretty simple. You may use either a digital level/angle gauge or your smartphone with a protractor app. It seems there are many products in 58mm square size, for example, this one. So I made 59mm height holder. I also made a holder with 150mm height, which hopefully covers many smartphones (in vertical orientation).
When you can measure the camber, then theoretically you can measure the caster as well.

Toe measurement
The toe measurement is typical “tape measure method”(I’m not sure how to call it). You can either just read the difference between front and rear of a wheel in millimeter, or calculate it in degree using triangle function.
For this, you will need a pair of tape measures, STABILA BM100 3m or similar. When the body of the tape measure is similar, it may work too. Please refer the picture where I explain the tape measure holders. Please be aware that the distance of those tape measure holders are important for the calculation by triangle function.

Alternatively, it can be used as a support tool for string alignment that uses a pair of long bars in the front and rear (please refer Horizontal setup in the picture).

String alignment option
The result you can get by the tape measures is “total toe” (total amount of left and right toe angle). To “align” wheels, you probably want to care about the thrust angle (difference of L and R rear toe) to let the car driving straight, or the steering wheel to be centered.

Usually, string alignment needs a pair of long bars to be placed in front and rear of the car. However, for this DIY wheel alignment gauge, you can attach rulers to the tape measure holders to obtain similar functionality, so you can run a thin strings from front to rear and use it as reference for adjusting left and right toe angle individually.
Using the adjustable string holders on the ruler and the tape measures at both front and rear, you can set the string lines in parallel. Please see the picture where I explain about this function.
I made 3 types of the ruler holder for different widths.
13.2mm for KS TOOLS Flexible steel ruler 150mm 300.0101
15mm for Shinwa sokutei H-101A
16mm for other brands. Please choose one for your needs.

Carrying / storage
For carrying and storage, you may use Carrying / storage holder.

Disclaimer
This design provides series of parts to create your own gauge.
Since the result you achieve depends on your usage, I am not responsible for your result.
Please purchase/download only when you understand the concept and agree with it.
Of course, if you have question, find some problem in design, or in need for additional module, please contact me.

Update history
2023-10-30 Published
2023-11-11 Ruler holder v2.1 (minor correction)
2023-12-26 new modules
- 20x20 square tube connector Quick clamp version
- Angle gauge holder version 2
2024-01-01
- Ruler holder sliding piece v2.0 M3 insert with string hook
- Ruler holder sliding piece clip v3.0 with string hook
- Tape measure holder 01 v2.1 (minor correction)
- Tape measure holder 02 v2.1 (minor correction)
2024-01-31 new parts/modules
- Steering hook
- Steering wheel holder base plate
2024-03-16
- End cap 20x20 for t1.0, 1.5, 2.0 and 3.0
2024-04-15
- Ruler holder 01 v3.0 13.2mm
- Ruler holder 01 v3.0 15mm
- Ruler holder 01 v3.0 16mm
- Ruler holder M4 sliding nut