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

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spillemand
Posts: 2
Joined: 29 Oct 2018, 10:00am

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

Postby spillemand » 30 Oct 2018, 12:24pm

Thanks a lot!!!!!!!!
Now I am trying to figure out my wheels..........................Timewill tell!

Brucey
Posts: 41064
Joined: 4 Jan 2012, 6:25pm

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

Postby Brucey » 24 Nov 2019, 4:54pm

an omission in this thread is a recipe for building 36h rim onto a 40h hub. TBH it is so much easier to build a 32h rim onto a 40h hub I would suggest that you do that instead. But if you really want to, the recipe is as follows.

1) label the spoke holes on the DS flange A to T running clockwise.
2) Block holes J and T (you won't be using these and something in the hole will stop you from trying)
3) block two holes in the opposite flange such that the blocked holes are opposite the midpoint between D and E on the nearside flange and N and O on the nearside flange.


Spoke lengths (for a nominal 'x3' wheel) are as follows;


A Leading x2.59
B Trailing x3.31
C Leading x2.79
D Trailing x3.11
E Leading x2.99
F Trailing x2.91
G Leading x3.19
H Trailing x2.71
I Leading x3.39
J (not used)
K Trailing x3.41
L Leading x2.69
M Trailing x3.21
N Leading x2.89
O Trailing x3.01
P Leading x3.09
Q Trailing x2.81
R Leading x3.29
S Trailing x2.61
T (not used)

You can use spoke A as the lead spoke, so that it goes immediately left of the valve hole when the valve hole is uppermost in the rim.

When labelling the NDS flange, be sure to label the spoke holes in the same direction running around the flange (i.e. CW as viewed from the DS of the wheel) and use the drilling opposite O-P as spoke A (provided the rim has a RH (CW) stagger). Then just follow the recipe as before.

When calculating the spoke lengths, work out as per normal for a 36h wheel, but use the fractional crossing values as listed.

A very typical build is to use an old 40h Sturmey Archer hub; sample spoke lengths for this combination are (assuming 66.5mm flange diameter and 600mm ERD, which gives 285.0mm spoke length in an undished 36/36 x3 wheel);

A Leading x2.59 280.9mm
B Trailing x3.31 288.3mm
C Leading x2.79 282.8mm
D Trailing x3.11 286.2mm
E Leading x2.99 284.9mm
F Trailing x2.91 284.1mm
G Leading x3.19 287.0mm
H Trailing x2.71 282.0mm
I Leading x3.39 289.2mm
J (not used)
K Trailing x3.41 289.5mm
L Leading x2.69 281.8mm
M Trailing x3.21 287.3mm
N Leading x2.89 283.9mm
O Trailing x3.01 285.1mm
P Leading x3.09 286.0mm
Q Trailing x2.81 283.0mm
R Leading x3.29 288.1mm
S Trailing x2.61 281.0mm
T (not used)

This recipe has the sum of all leading crossings almost exactly equal to the sum of all trailing crossings, so (unlike my first effort) it won't build into an 'unbalanced flange'.


[If you build with two unbalanced flanges then either

a) the wheel will have leading spokes too long and trailing spokes too short (or vice versa) (wheel built symmetric) or

b) the hub will end up with a residual torsion stress in it (and all leading spokes tight on one flange and loose on the other) (wheel built with unbalanced spoke pattern in opposite directions on each flange) ]


You can see that by rounding (e.g. upwards) you can use (say) 282, 284, 286, 288 and 290mm spoke lengths and you will never have more than an error of more than ~+1mm in spoke length.


cheers
Last edited by Brucey on 24 Nov 2019, 6:53pm, edited 5 times in total.
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

robc02
Posts: 1726
Joined: 23 Apr 2009, 7:12pm
Location: Stafford

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

Postby robc02 » 24 Nov 2019, 6:07pm

Brucey wrote:an omission in this thread is a recipe for building 36h rim onto a 40h hub. TBH it is so much easier to build a 32h rim onto a 40h hub I would suggest that you do that instead. ..........

cheers

I did one of these quite a few years ago - I still have it in fact.

I had just acquired an old Sturmey Archer 40H hub and wanted to try it out for as little cost as possible. So I drew a scale diagram of the the spoking pattern at the hub, applied a bit of trig, and rounded the results to the nearest mm or two. I then sifted through a box of used spokes and found the nearest lengths to my calculated values. Surprisingly, perhaps, the wheel went together with only a couple of spoke swaps (probably due to the slightly slapdash nature of my sift through the used spokes!).

So it worked well and proved the point..... but, as suggested above, I decided to use 32H rims in future!

EDIT: Just realised I posted this info in an earlier post a good while ago.

mattsccm
Posts: 3467
Joined: 28 Nov 2009, 9:44pm

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

Postby mattsccm » 24 Nov 2019, 6:21pm

Wohoo. Maybe you have given me a way of using some spare rims to go on my 40 hole trike hubs. I'm too tight to buy new rims.

nez
Posts: 1840
Joined: 19 Jun 2008, 12:11am

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

Postby nez » 25 Nov 2019, 5:47pm

Reading this thread is making me dizzy

Cyril Haearn
Posts: 14336
Joined: 30 Nov 2013, 11:26am
Location: Leafy suburbia

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

Postby Cyril Haearn » 25 Nov 2019, 7:19pm

Quite pleased with my fixed back wheel, 32 spoke rim and hub, I have 36 on the front, minusplus? But the back wheel is not dished, +1
I am not heavy and I try to ride smoothly, may I expect many years service with 32 spokes on the back?
Entertainer, intellectual, idealist, PoB, 30120
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Pneumant
Posts: 188
Joined: 7 Oct 2010, 8:25pm

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

Postby Pneumant » 25 Nov 2019, 9:24pm

Brucey wrote: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


Ye Gods >> Seven different spoke lengths in one wheel :shock: - makes me feel unworthy!
These well written tech articles are what makes this forum so good 8) .

thecycleclinic
Posts: 180
Joined: 20 Apr 2012, 8:58pm

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

Postby thecycleclinic » 1 Dec 2019, 9:23pm

I'd just buy matching components. Wah to.mucb effort for.a commercial build. For a personal.build you really have to want to/ be too tight to buy new bits.

H Plus Son still do 36h rims. Kinlin do the adhn Nd there are others. What's wrong with 36 spoke front and 32 rear. Its ot atheistic. Also given the flange spacing of a dynamo hub a 36 spoke front might still.nlt be a laterally stiff a 32 spoke rear.

Brucey
Posts: 41064
Joined: 4 Jan 2012, 6:25pm

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

Postby Brucey » 4 Dec 2019, 10:34am

thecycleclinic wrote: ….For a personal.build you really have to want to/ be too tight to buy new bits...…...I'd just buy matching components.....


if you can do. But that isn't always possible and it seems rather wasteful in many cases; for example the disc brake wheel I mentioned upthread was built using a cheap hub that I already had and a rim that had already had a life as a rim brake wheel. Being 'tight' in your eyes is 'not being wasteful' in others. Others simply don't have the money (*).

Wah to.mucb effort for.a commercial build
.

I never said it wasn't (**). But most people that build wheels commercially have never tried this and -once you have a recipe- it isn't anything like as bad as you might expect. You just can't lace a wheel with your eyes closed this way though; even if you are an experienced wheelbuilder you will need to engage brain.

H Plus Son still do 36h rims. Kinlin do the adhn Nd there are others. What's wrong with 36 spoke front and 32 rear. Its ot atheistic. Also given the flange spacing of a dynamo hub a 36 spoke front might still.nlt be a laterally stiff a 32 spoke rear.


The flange spacing of a typical cassette hub is only three or four mm wider than (say) a shimano DH for disc brakes. However the dish in a typical rear wheel means that the lateral stiffness is heavily compromised. IMHO a 'well balanced' wheelset (with undished wheels using standard hubs, for normal loads) would be with 10-15% fewer spokes in the front than the back. Or much lighter-built spokes/rim in the front. If the rear wheel is heavily dished, and the front wheel has widely spaced flanges, you can easily go more than this.

IMHO the modern practice of using the same spoke count and rims front and rear only make sense (on the road) if you are going to carry a front load and is otherwise something of an abomination; locally I estimate that bike shops replace or rebuild rear wheels about three or four times as often as fronts and this is a good part of the reason why.

(*) BITD I simply didn't have the money to buy the parts I wanted; however I found that I was able to buy such things as excellent 6400 series cassette hubs in 36 drilling for sensible money and I built these into all kinds of wheels. For example a set of 28h race rims can be built onto almost any other hubs and can be built radial throughout apart from 14 spokes on the drive side. So it is only 14 spokes that are in any way more complicated than normal; hardly a big challenge (once you have the recipe) or particularly time-consuming either.

(**) Commercially a few manufacturers have produced hubs with odd-shaped flanges that could only be built with multiple different spoke lengths. For example the original Pedersen 3s hubs (two-shaft type) were made with egg-shaped flanges initially. However after a few years (during which time wheelbuilders presumably moaned incessantly that it was 'too complicated' to build wheels this way) they changed to round flanges. The end result was a worse wheel (heavier and weaker because tall steel flanges are either and/or both) but easier to build.

Note that some folk are (say) leery of touring on wheels that are built as strong as they ought to be (eg on 40h or 48h hubs for tandems and heavily loaded solos) because (they say) 'you can't buy another rim if you have to'. So they ride round on wheels that are more likely to give trouble instead....? It hardly makes sense. When I get a few minutes spare I shall work out recipes for building 32h and 36h rims onto 40h and 48h hubs and maybe this (as an emergency backup plan for temporary use) will take some of the fear out of using these (stronger, better) wheels for touring on.

cheers
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