I'm about to commission having a WM3 x 19" rim fitted to a spare hub, which will eventually be fitted to my 1972 Fastback.
The workshop manual offers spec.s for the spokes, but not for what if any offset should be applied, relative to the hub.
There's a hopelessly inconclusive discussion on the NOC technical forum (here: https://www.nortonownersclub.org/.../techni.../wheel-offsets) and I'm also aware of the advice sheet on wheel offsets on RGM's website.
One issue that seems to bedevil all the references that I can find, including in this forum, is that people invariably discuss the matter in terms of offsets from the swinging arm, hub faces, etc., measured to one side of the rim.
This may be helpful from the point of view of checking wheels in situ (provided one allows for differences in rim width between different types and makes of rim of a given nominal size).
But from the point of view of building one from scratch surely what one needs to know is the location of the centre line of the rim relative to the centre line of the hub (this latter defined as half-way between the hub flanges)?
Can anyone say what this should be?
dimensions
one recent note I had from the NSW owners club notes in Australia: centre of rim to outer face of brake drum ( brake plate removed) is 3 and 3/8 inches.
this looks to agree with my bike in a quick check by eye.
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Is this any help?
In case this thread is of any use....
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A quick update; I thought I…
A quick update; I thought I'd check what's on my bike now, using the rough-and-ready method of placing a straight-edge across the tyre walls and measuring the distance from that to the spoke flanges on the hub.
Measuring several times at different points I consistently get 1.00" on RHS, 0.50" on LHS, implying that the rim is offset 0.25" to the RHS, relative to the hub.
Tyre is 4.10 Avon Roadrunner, traditional type; rim is WM2 chromed steel.
Interestingly I got these results before consulting these:
which suggest a figure that corresponds exactly to my measurements.
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or centre of rim relative to one named side of the hub. I agree it is not ideal to give a measurement from one side of rim, especially as this is often quoted without specifying the rim!