32 hole rim onto 36 hole hub - "alphabetti spoketti"

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robc02
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Re: 32 hole rim onto 36 hole hub

Postby robc02 » 3 Dec 2017, 12:43pm

Some years ago I did a similar thing with a 36 hole rim on a 40 hole Sturmey Archer hub - so large flange. I worked out the variation from standard calculated lengths by drawing approximately to scale sketches of the spoke positions in a 36 hole hub then superimposed those for the 40 hole hub. A bit of simple trig allowed me to finalise the lengths.

While it was successful it was a bit of a faff, so now I build my 40 hole SA hubs with 32 hole rims. This is much simpler, requiring only two spoke lengths.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: 32 hole rim onto 36 hole hub

Postby Brucey » 3 Dec 2017, 12:49pm

robc02 wrote: ....I build my 40 hole SA hubs with 32 hole rims. This is much simpler, requiring only two spoke lengths.


yes indeed that is a good way to go.

cheers
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Brucey
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Re: 32 hole rim onto 36 hole hub

Postby Brucey » 3 Dec 2017, 1:26pm

for building a 32h rim onto a 40h hub you can plan to do it by reference to the 32/36 figure below

Image

with the following changes

1. Imagine there to be another unused hole in the flange between positions marked 'D'

2. Calculate spoke lengths for 32 spoke wheel but (if building x3) use fractional crossing values of

x3.1 for spokes B and C and
x2.7 for spokes A and D

as per the previous recipe, be sure to lace the spokes carefully, following the pattern closely. There is an alternative pattern that uses x2.9 and x3.3 instead; needless to say these spoke lengths won't work in the pattern depicted and vice versa.

cheers
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Brucey
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Re: 32 hole rim onto 36 hole hub

Postby Brucey » 3 Dec 2017, 3:18pm

whilst I am on a roll, here is a recipe for lacing 28h rim x2 onto a 36h hub. Seven spoke lengths are required, A-G.

This photograph shows the lacing on one half of one flange (NB the spokes are through the flange, but are not attached to a rim, so the angles are not correct)

Image267.jpg
more alphabetti spoketti


This spoke pattern is mirrored on the other half of the hub flange so spokes are as follows, starting on the left, running clockwise around one flange, showing spoke orientation and fractional crossing value

A1, inside, leading, x2.11
B1, outside, trailing, x1.67
--unused hole in flange--
C1, inside, leading, x1.78
D1, outside, trailing, x2.00
E1, inside, leading, x2.22
--unused hole in flange--
F1, outside, trailing, x2.33
G1, inside, leading , x1.89
-----------mirror line--------
G2,outside, trailing, x1.89
F2, inside, leading, x2.33
--unused hole in flange--
E2, outside, trailing, x2.22
D2, inside, leading, x2.00
C2, outside, trailing, x1.78
--unused hole in flange--
B2, inside, leading, x1.67
A2, outside, trailing, x2.11

Calculate spoke lengths as for a 28 hole hub, using the fractional crossing values.
The mirrored spoking pattern is necessary because otherwise there would (amongst other things) be a net torque on each flange.

Note that for any given spoke letter, the lengths are the same in each half of the pattern, but the orientation is different; a letter spoke (eg A) that was "inside, leading" in the top half of the pattern becomes "outside, trailing" in the lower half of the pattern.

Unlike most other patterns, the spoke lengths will work out perfectly if the pattern on the left flange is rotated exactly 90 degrees vs the pattern on the right flange, i.e. so that there is a 90 degree rotation angle between the four type 'D' spokes. You can of course swap inside and outside positions in the pattern on one flange, but you can't change leading for trailing in the same way.

cheers
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Brucey
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Re: 32 hole rim onto 36 hole hub

Postby Brucey » 4 Dec 2017, 8:16pm

as mentioned in a previous post, for rims that have a number of spokes on each hub flange that isn't divisible by four (eg 28h) there is another type of solution that you could call 'semi-spanish' spoking, in which case the pattern on each flange is rendered more symmetric by inclusion of a few radial spokes into an otherwise crossed pattern. I first built a set of wheels (28h rim onto 36h hub) using this type of pattern about 25 years ago and they worked fine.

It turns out that there is a write-up about a similar approach on the Sheldon Brown site, here

https://www.sheldonbrown.com/mismatch/

which builds this pattern

Image

The unused spoke holes in the 36h flange are between the green and red positions. The grey spokes are on the other (rearward) flange.

if you read the above page it suggests that you calculate the spoke lengths using the included angles as per the longhand equation that describes the spoke length calculation. This is quite enough to put a lot of people off: My suggestion is that if you want to build a wheel this way, you should use a spoke length calculator and you should enter a fractional crossing value instead, which will be a lot quicker and easier.

These are the fractional crossing values you should enter into a calculation (that is otherwise for a 28h wheel)

Spoke--------Fractional crossing value

Red-----------x0.0
Green--------x2.56
Green(alt)---x1.78
Magenta------x1.67
Blue----------x1.89

The Green(alt) value is to be used when the Green spokes are in the unused flange holes as depicted in the picture above. You may wish to do this if you think the rim entry angle is a bit too much otherwise.

In full 'Spanish spoking' all the spokes are arranged in triplets, so this spoking pattern is only used throughout on 24h and 36h wheels, typically. It entails that three spokes cross over one another at the same place: I suggest that the triplets may be best achieved by not bracing the crossing of the (near) tangential spokes, and that the radial spoke is perhaps placed between them. However there are many ways of doing it and none of them are perfect, in fact.

In choosing between the semi-Spanish and the modified x2 pattern (in the previous post), I'd suggest that the latter is likely to have more even spoke tension and (at a distance, and despite the lower symmetry value) looks more like a normal wheel. It is a bit more complicated to build though, requiring more different spoke lengths. The semi-spanish pattern looks a bit wacky by comparison, which some folk may prefer, because it gives their bike a distinctive look.
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Samuel D
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Location: Paris

Re: 32 hole rim onto 36 hole hub

Postby Samuel D » 4 Dec 2017, 8:28pm

Brucey wrote:…semi-Spanish…

Sounds like a chess opening! (But apparently it’s more complex than that.)

I’m glad you periodically publish threads like this one so that your findings can be accessed by others. It might be worth saving them in the Wayback Machine to increase the odds of the info being available many years in the future. You can manually invoke a save by searching for the URL and clicking “Save this url in the Wayback Machine” when the “Hrm” error message appears. Just a thought.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: 32 hole rim onto 36 hole hub

Postby Brucey » 5 Dec 2017, 11:24pm

that is not a bad idea.

cheers
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Brucey
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Re: 32 hole rim onto 36 hole hub

Postby Brucey » 6 Dec 2017, 4:57pm

another wacky pattern is this one, which I call 'fannish spoking'

Image268.jpg
36h Fannish spoking


Image269.jpg
a single fan of six spokes


This does nothing for wheel strength, but then again it isn't particularly harmful, either. I wouldn't recommend it for hubs with weak flanges or for wheels that see a lot of torque through the hub (so not for brake hubs or perhaps SF rears). Its raison d'etre is mainly to look different. Just a bit of fun.

[edit; actually there is one small practical advantage in service; it much is easier to reach between the spokes and clean the hub, with this pattern.]

However it is potentially very easy to build; all the spokes are the same length (as for a standard x3 wheel) and there is only one braced crossing in each fan. The wheel in the picture was originally built x3 symmetric; I just moved 12 spokes to convert to the revised 'fannish' pattern. If lacing from scratch, it is probably easiest to build skew (i.e. so that the inside spokes on one flange are leading, and on the other flange trailing). This allows you to put all the inside spokes in first , and all the outside spokes in without any obstruction, other than the six (total) braced crossings.

There is an analogous pattern (with four smaller 'fans' of four spokes each side of the wheel) which you can create using a 32x2 wheel as a starting point. Again the spoke lengths are identical to the usual ones you would use for a 32x2 wheel.

cheers
Last edited by Brucey on 7 Dec 2017, 4:23pm, edited 1 time in total.
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brynpoeth
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Re: 32 hole rim onto 36 hole hub

Postby brynpoeth » 6 Dec 2017, 7:42pm

Brucey for PM
Or Professor at least
He seems to know everything :wink:
Entertainer, kidult, curmudgeon
Cycling-of course, but it is far better on a Gillott
We love safety cameras, we love life

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: 32 hole rim onto 36 hole hub

Postby Brucey » 7 Dec 2017, 4:16pm

brynpoeth wrote:Brucey for PM....Or Professor at least....


steady on! :lol:

This is a recipe for a 28h rim x2 onto a 32h hub. Again (as per the 28/36 x2 recipe) there are seven spoke lengths required.

Image270.jpg
28 into 32 will go...sort of....


The pattern above is mirrored onto the other half of each flange so CW from the left the spokes run as follows;

-----------mirror line + unused hole in flange----------
A1, inside, leading, x1.63
B1, outside, trailing, x2.25
C1, inside, leading, x1.88
D1, outside, trailing, x2.00
E1, inside, leading, x2.13
F1, outside, trailing, x1.75
G1, inside, leading , x2.38
-----------mirror line + unused hole in flange----------
G2,outside, trailing, x2.38
F2, inside, leading, x1.75
E2, outside, trailing, x2.13
D2, inside, leading, x2.00
C2, outside, trailing, x1.88
B2, inside, leading, x2.25
A2, outside, trailing, x1.63
-----------mirror line + unused hole in flange----------(start point)

The pattern on the second flange will line up (almost? * ) perfectly if it is not rotated from the first side.

[edit: (*) if there is an error, it is ~1.6 degrees, which corresponds with a crossing error of +/- x0.06 on the second flange. This amounts to an error in spoke length of 0.5mm on the second flange for a 28x2 build on a 60mm dia hub.]

cheers
Last edited by Brucey on 11 Dec 2017, 5:49pm, edited 2 times in total.
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Brucey
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Re: 32 hole rim onto 36 hole hub

Postby Brucey » 8 Dec 2017, 5:08pm

this is an example of 24-spoke Spanish spoking

Image

the triplets are laced in an odd way for sure but maybe that is the way it works out best when the crossings are that close to the flange. This pattern is normally used on larger flanges, which avoids the crossings being that close to the hub.

The semi-tangent (crossing spokes) are standard x2 length for a 24 spoke wheel. The radial spokes are, erm, the correct length for radial spokes.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Brucey
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Re: 32 hole rim onto 36 hole hub

Postby Brucey » 8 Dec 2017, 5:17pm

this is an example of 36-spoke Spanish spoking

Image

which some folk call crowsfoot spoking. In this variant the crossing spokes make a standard crossing of another single spoke as well as the triplet crossing.

As you can see the triplets are not all laced the same way.

The crossing spokes in this pattern are the usual length for 36x3 spoking.

cheers
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spillemand
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Joined: 29 Oct 2018, 10:00am

Re: 32 hole rim onto 36 hole hub - "alphabetti spoketti"

Postby spillemand » 29 Oct 2018, 12:39pm

Could you post a picture of a whole wheel with 36h hub and 32h rim?

Brucey
Posts: 35850
Joined: 4 Jan 2012, 6:25pm

Re: 32 hole rim onto 36 hole hub - "alphabetti spoketti"

Postby Brucey » 29 Oct 2018, 7:44pm

sure. Might be a day or two through.

cheers
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Brucey
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Re: 32 hole rim onto 36 hole hub - "alphabetti spoketti"

Postby Brucey » 30 Oct 2018, 8:45am

photos as promised

Image01348.jpg
unused holes in hub at NE and SW compass points


Image01347.jpg


for the most part, the wheel just looks like, er, 'a wheel'. You need to look carefully to see that there are unused spoke holes in the hub.

cheers
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