28h rims with 32/36h hubs? ever laced one?

ant said:

i have access to a bunch of nice 28 hole rims that i think will go quite cheap. is there any way
to lace a 28 hole rim to a 32 or 36 hole hub? id be willing to do a pretty complex, odd lacing,
multi-spokelength job just to make it work, but i dont really know where to start, or if the
factors mean that 28 just cant be used unless you're buildign an 8 spoke wheel.

You _could_ lace a 28 hole rim to any hub, but things will start to get complicated because of the
number of different spoke lengths you may end up using. It could go something like this:

For a front wheel, make sure you have the same number of holes on both sides of the hub, and evenly
spread on the rim. You might want to think about radial lacing on the front, to cut down on the
different spoke lengths.

24 hole hub - leave a hole at positions 1, 8, 15 and 22 in the rim - not recomended.

32 hole hub - leave a hole at positions 1, 9, 17 and 25 in the hub (where the first 16 numbers go
around one flange and the remaining numbers go around the other flange)

36 hole hub - there is no perfectly symetrical way of doing this with all 28 spokes. I would not
recommend building a wheel where you use 24 spokes on a 36 hole rim, which would be the largest
spoked symetrical pattern you could achieve.

I would doubt the advisability of making a rear wheel for anything but light loads with gaps between
the spoke holes in the rim, (so a 24 spoke hub is out).

This gets you a wheel and a headache trying to calculate what spoke lengths you need. It may also be
difficult to get round and true with even spoke tension.

Quoted message said:

anyone done anything like this?

Only as a bodge, and a last ditch one at that. If your rims have offsets for the spoke holes (i.e.
half point left and half point right) you could end up with a dangerous wheel. Same goes for leaving
holes at the wheel rim.

Quoted message said:

(or does anyone know where i can find dirt cheap 28 hole hubs? 😉

Google?

--
Jim Price

jimprice.dsl.pipex.comjimprice.dsl.pipex.comOpen ↗

Conscientious objection is hard work in an economic war.

In message <[email hidden]>, Jim Price <[email hidden]> writes

Quoted message said:

ant wrote:

snip)

Quoted message said:

Quoted message said:

i have access to a bunch of nice 28 hole rims that i think will go

This gets you a wheel and a headache trying to calculate what spoke lengths you need. It may also
be difficult to get round and true with even spoke tension.

Quoted message said:

anyone done anything like this?

I've not tried it but have seen this page on how to get the spoke lengths needed for 24 hole rims
and 36 hole hubs by using spocalc with cross numbers as a decimal:

damonrinard.com36 24.htmOpen ↗

I think once you look at other mixtures things get harder. Looking at every other spoke on a side
(either all the leaders or all trailers) and going the way round the flange the spokes point, the
error due to having too many holes in the flange should start negative right after a missed hole
pass through zero and then build up as you approach the next missed hole. (Each of the spokes in
the run of used holes lies at a different angle to the radial line through its flange hole.) If
this is correct, the 36/24 works with equal spoke lengths because every spoke is the first after a
missed hole.

Does this make sense?

With 28 hole rims and 36 hole hubs there are 4 holes to skip on each hub flange and as 4 is not a
factor of 18 you will end up with runs of adjacent used holes going 3-4-3-4 on each flange. I think
if you work out the fraction like he does on the web page but for each spoke in a run it should be
OK as far as spoke lengths goes.

(Unless you are building lots of wheels you may end up paying out a lot on spokes if you have to buy
several different lengths. You might do want to compare getting the 28 hole hubs and getting a good
discount on spokes by the box.)

I have found spocalc itself very useful as you can adjust the figures to account for more or less
dishing very easily.

Martyn

Martyn Aldis, e-mail [email hidden]
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