Inherent in any reasonably random assembly of hacking materials are all sorts of technical and physical limitations, but also an unknown number of potential opportunities and undiscovered uses. In view of this ”profound insight”, it would be a waste of time to begin a project such as this by making detailed plans and drawings for the expected end product. Instead, invention, inspiration and ultimately solutions tend to appear ”organically” during the actual hands-on building process. Nevertheless, the following properties were deemed critical for an adequate truing stand:
- Structurally rigid and non-yielding in use
- OLD (over locknut dimension) to be adjustable between 100 – 140 mm.
- Good fit for both front and rear axles (9, 9.5 and 10 mm)
- Rim diameter to be adjustable in the range 357 – 635 mm (17" to 700B)
- Real-time analog and digital representation of the entire rim's lateral alignment, using a PC
- Configurable for 16, 20, 24, 28, 32, 36, 40 and 48 spokes
- Good repeatability and stability of measurements
A couple of further decisions were made at an early phase of development:
Firstly, that it was essential to be able to accurately detect lateral misalignment, but not so for radial misalignment (the eccentricity, or lack of ”roundness”). As a non-profesional wheel builder I like/need to be slow and deliberate. The radial (up-and-down) dimension of trueness is then rarely a problem to check, in my experience, and may just as well be simultaneously "eye-balled as usual”. Besides, it can be argued that any small bumps in this plane, as a result of slightly varying radii along the rim's perimeter, will probably appear insignificant compared to the typical uneveness of tyres (regardless of brand).
Secondly, a facility for exact centering wasn't included in the brief, since it is straightforward to achieve this using a separate dishing tool. The procedure of switching the wheel repeatedly from one tool to another does not improve building speed, but then again, as an enthusiast I don't really mind. Actually I would be disappointed if the fun didn't last long!
And here – ta-dah! – is the final result: The DRO True Detective apparatus!