|By Paul Bartholomew||Part one here|
up your late Chief wheel for truing, the brake drum will need to be installed,
complete with wheel bearings and an appropriate axle. Besides your
truing stand, make sure you have the following things on hand: A decent
spoke wrench, a ruler, a straightedge, and, if you are working with stainless,
a lubricant designed for stainless steel. A lacing stand is nice, but not
a complete necessity. One can be easily fabricated. If nothing
else, you can invert your forks, and attach two stiff wires as indicators
to show where the relative runout is. Remember, when truing late
Chief wheels, keep in mind the offset. (2 15/16” on pre ’46 wheels
and 2 5/16” on ‘46-’53).
Once you have the proper lacing pattern, now you can start working toward proper offset, concentricy and lateral trueness. As was mentioned in the lacing installment, concentricy is initially set by the “inside” sets of spokes, while the “outside” sets are used more to pull the wheel into true. Again, they all need to come together in the end with all the above factors plus proper tension.
Metal has excellent memory, and can be distorted - then return to its original shape, within reason. This is why some people come down on the side of not torquing down the spokes too much. As those good bodymen out there will agree, having the wheel in too much tension will increase the likelihood that a severe pothole will actually bend the rim, as the force is not allowed to go anywhere else. But, as you may suspect, it is a fine balance. Don’t forego proper tension, just because you’ve found that “sweet spot” of concentricy and lateral trueness.
|Click on pictures for full size|
offset, from the reference materials I’ve seen, call for a measurement
from the NON-brakeside face of the hub to the center of the rim.
Those are the figures given earlier. Since that is not really an
easy measurement to make, measure the width of the rim, divide this in
two, then subtract this figure from the previous offset amount, (may be
a positive or negative sum, depending on rim width and year of hub).
This way you can set up a straightedge in the plane that is across the
outside edge of the rim. Now you can make an easy measurement to
the face of the hub. See example to the right of here
Start the process by incrementally tightening every spoke to a semi firm state, starting at the valve stem hole for reference. Just get the nipples engaged the same amount all around at first, regardless of whether some are looser than others. Start measuring the lateral truing. When making adjustments laterally, find the worst spot, then loosen the spokes on the inside of the direction you are trying to pull it, then tighten neighboring outside spokes the same amount – try a half turn, and see where you’re at. Always keep your straightedge handy, so you’ll be able to keep making those measurements and keep track of that offset. Alternate sides, and you’ll start getting some real result, and start to feel pretty confident about your choice to true your own wheels.
Example of how to find an easier offset measurement (click)
it pretty close before you move onto the harder part, which is concentricy,
or vertical truing. It will take a bit more turns to make a difference
concentrically than you get laterally. Hopefully you will not have
exhausted the limits of tension aspect through your lateral truing.
If so, don’t’ sweat it, you can always back everything off a ¼ turn
or so and not be set back too much. (This isn’t a real quick process).
Find the high spot, then make a ½ turn on the spokes directly under
it. Always tighten when doing vertical truing. At this point
in the truing process, the tensions are getting up there and you have to
concern yourself with the physical characteristics of the metal you are
working with, probably stainless. In any case, as the tension increases,
the torsional resistance at the nipple increases, also. The effect
is that the metal is twisting to accommodate the turning action of the
nipple, if only slightly, and with the plastic memory of steel, it will
eventually work itself out if you don’t account for it. To overcome
it, make your spoke turns a little bit further, then back them off, much
the way you would tune a guitar. Also, some people use a hard rubber
hammer to smack the spokes to “seat” them. Especially do this near
the hub, and at crossings. Tap at them in different directions.
Also, you can use a light wooden mallet just to go around in the free area
of the spokes, tap them, and listen for the sharp tone. I’m not suggesting
that you “tune” them this way, but you will be able to tell relative differences
that might indicate a problem, such as a seriously undertensioned spoke.
Hopefully this will get you through the process. If you are particulally energetic, you might opt to remove the wheel after a 1000 miles or so to check the trueness. PS – while you have your truing stand set up, check some other wheels that you might have. You might be surprised to find vibrations or other handling problems you’d been blaming on other factors may in part be due to a seriously out of true wheel.
|Some additional info in Stan's September article here|