Paired-spoke hub laced to standard-drilled rim?
Dave
paired spoke wheels that I'd like to relace into a pair of rims with
standard drilling, wondering whether this is possible. The front hub
and rear NDS spokes are all nailhead spokes, the rear DS spokes are j-
bend into a flange.
Anyone have any experience with this?
Chalo
If you can determine the angle at which the hub holes diverge from
normal, you can express this as a fractional crossing when you enter
the data into Spocalc or another spoke calculator that allows
fractional cross numbers.
For instance, a 36 hole wheel has 18 holes per hub flange, spaced at
20 degree intervals. So in that case, 20 degrees equals one "cross".
If some of the hub holes are 10 degrees out of phase, then you could
specify 2.5-cross or 3.5-cross as applicable to calculate the spoke
lengths for those holes.
This is the technique I use to do skip-hole lacing that matches (for
instance) a 36 hole hub to a 24 hole rim.
http://www.rideyourbike.com/36hub24rim.shtml
Chalo
D'ohBoy
Been there, well, kinda... did a 2:1 rear rim with a standard-spaced
hub. Rim was evenly spaced but going 1:1 from 2:1 means the spoke
line for a buncha the spokes was 'suboptimal' due to drilling for the
other side of the hub. Your spoke line will prolly be less than
stellar too. But you can 'correct' the spoke line by bending the
spokes near the nipples. Both of these spoke configurations (mine and
yours) are definitely suboptimal., even with correction.
Don't have any longterm data on that - my buddy's been riding it for
about two months as his rear training wheel and hasn't had a failure
or truing required.
Good luck with that. This sort of mucking about is not for the faint
of heart ;) - especially the rider of said wheels.
D'ohBoy
Coldbeer
I've done it.
Paired-spoke hubs have spoke holes drilled directly opposite each
other whereas standard hubs are drilled so that the hole on the one
flange is directly between two holes on the other flange. This causes
every second spoke to be too short. You'll need four different spoke
lengths in two sets (left and right flange). Calculate the length for
one set on each flange using the standard method. For the other set
for each flange, add some length. Determine this additional length by
adding one quarter of the distance between two spoke holes on a
particular flange. In other words, you need an additional dimension
which is the distance from spoke hole to spoke hole.
Now you just have to figure out which way the hub will rotate for the
crossings and configure it so that the longer spokes travel the longer
distance.