<
[email protected]> wrote in message
news:a8%[email protected]...
> anonymous writes timidly:
>
> > I just put together a truing stand with dial indicators for radial and lateral truing. Also, a
> > dish tool with a dial indicator. (No flames on this, please - I know that some will say that
> > this level of precision is overkill but I like making things.)
>
> > While Jobst's fine book suggests that dial indicators have some value, I haven't found any
> > reference that tells me what level of truing and dish accuracy is considered acceptable. I don't
> > have enough experience to know by look/feel/calipers when a wheel is considered good enough so I
> > can't translate build quality by those more subjective standards into objective measurement
> > criteria. What are reasonable targets in thousandths?
>
> Depending on what sort of brakes and pad clearance you use, lateral alignment between +-0.005 is
> fine. Just remember that brake pads drag on rear wheels anyway with dual pivot brakes because
> their higher mechanical advantage demands lower brake pad clearance. For this reason many
> professional riders leave the rear QR open on long climbs and Campagnolo switched back to a single
> pivot 1:1 ratio caliper for rear brakes.
>
> These are the criteria for trueness, aside from the need for uniform tension among spokes of the
> same side for rear wheels and all spokes for front wheels. It seems to me that if you are
> designing tools, the goal should already be known and the method of achieving that arrived upon
> from practice. Quantifying lateral and vertical trueness is one thing, but doing it so that it
> assists truing a wheel requires more than just that. It must be practical. Reading numbers may
> not be as useful to the experienced mechanic than watching an air gap between rim and gauge point
> grow and shrink when the wheel is rotated. This method has served well with good results for a
> long time.
>
> Jobst Brandt
[email protected] Palo Alto CA
Lateral error should be <.5 mm I suggest you get a copy of Barnett's Chapter 17 on Wheel Truing. I
think you will find that precision in tension balancing is more important than getting extremely
precise truing. Spoke alignment, proper spoke tension, tension balancing, and stress relieving are
all covered in Jobst's book. A quote from Wheelsmith's website at URL
http://www.wheelsmith.com/page4.html bears repeating: "Wheelsmith's wheelbuilding philosophy
emphasizes strength and durability, and the key is high, uniform spoke tension. Spoke tension is the
most difficult and elusive aspect of wheelbuilding. It is the characteristic of the wheel most
difficult to evaluate, yet the most critical to its performance. This approach to wheelbuilding,
based on combining both art and science, and focusing on tension rather than cosmetic trueness, was
pioneered by Wheelsmith and remains at the foundation of our process. Cosmetic trueness can actually
come at the expense of a wheel's strength because it can result in unbalanced tension. So do not be
misled by some builders' claims about trueness, because what really matters is not how true a wheel
is now, but how true it is 1,000 miles from now."
David Ornee, Western Springs, IL