jackbombay

There is an older thread here with some info on building one of these wheels, but it is missing information, specifically, the diameter of the hub flange he used for his calculations. I did some rough measuring and came to the conclusion that his numbers were for a sturmey archer hub, so I ordered the spokes and they worked.

Lacing a 32H rim to a 40H hub

Getting the right length spokes in their respective holes is obviously essential, and its not particularly intuitive, every other spoke from each side of the flange is "the other length spoke". The first 8 spokes you install will be 4 short ones and 4 long ones. So, I marked the hub to make this all fairly error proof. Black for holes that get no spokes, blue for holes that get longer spokes and red for holes that get shorter spokes.

I printed the PDF from the above thread and marked it with felt tip markers, and also marked my hub,





I initially laced up the 2nd side of the wheel "one hole off" accidentally as I tried to index it from the empty holes, but I messed that up, so I indexed it from the one of the central spokes of the group of 4 and got it right. I'm not claiming to be any sort of master wheelbuilder, I've laced up 15 or so wheels in my life, enough to have a decent Idea what I'm doing, but I certainly don't know all, or even most of the tricks...

At any rate, I REALLY like sturmey hubs, being able to lace them to modern rims is fantastic, hopefully this will encourage other people to build up sweet wheels for restomod builds based around sturmey hubs!

EDIT/// additional info, just to clarify, you calculate your spokes for a 32 hole hub and rims, then do the addition/subtraction noted above. For the 700c rim I used (ERD of 611) with a Sturmey hub my spoke lengths were 290 and 296, 16 of each.

mechanicmatt

Sounds awesome, we all want pics of what the whole wheel looks like.

JaccoW

That looks great and +1 on @mechanicmatt's comment, we want pictures!
Especially interested in what the angles look like near the rim.

I have an alloy 40H FM-hub that needs a rim but I'm not sure I dare to lace that one up like this. Or maybe I should just try and see how it works.

J.Higgins 

I admire your tenacity, Jack, but why not simply use a 40H rim? I too love the SA hubs, but there are many places to get 40H rims, or custom drillings. No malice intended here; I'm just curious why you chose to do this.

JaccoW

Not anymore in my experience, and certainly not in anything remotely C&V worthy. And even if there is, there is rarely a matching 32H rim for the front anymore. e.g. Kinlin 700C 40H rim or the only in black Velocity Dyad

Even old stock of Sun or Velocity rims is hard to come by and practically non-existent in Europe.
The only one I am aware of is Cycles Grand Bois and those are expensive rims with expensive shipping.

jackbombay

More pics!

Side view,



The angle the spokes meet the rim,



And I stuffed some black neoprene kneepads inside the wheel so you can see the pattern of one side of the wheel clearly,

jackbombay

I would totally lace it up like this! The altered pattern is hardly notable, I can see wanting to stay period correct and build a 40 spoke rim for it, but if that isn't a concern of yours you should absolutely do it!

I have found some 40 hole rims, but they are usually tandem rims, and heavy, and expensive, and they don't make a matching front rim in 32. Plus, I like to have the same number of spokes in both wheels for a symmetrical look.

Yep, and if you want to go with a 14mm internal width rim to work well with a 25 or 28c tire you're out of luck.


The other option to use modern rims with a sturmey hub is to get a 28 hole sturmey and build a 28 hole wheelset, but that only works if you have/want a steel shell AW, which I love, but sturmey made so many other hubs that are very cool. My super awesome townie has a 28 hole sturmey AW for the rear wheel, and I swapped the internals into it from an S5, which is great functionally, but not using the five speed hubshell is a bit sad given their relative rarity, but even if I did build up another wheel for that bike with the S5 hubshell then I would have 32 spokes in the rear and 28 up front. As I'm building this bike from scratch for a friend I had the option to build a 32 hole wheelset so I took it!

JaccoW

Well, the 40H alloy hubs are prone to crack and explode! They do seem to be a fairly direct swap with steel AW shells.

cadillacmike68

OK, you got it done, I wouldn't have tried, but more power to you.

A steel hub won't break, but watch the spokes, some of them look like they will be taking a larger stress load and there are 8 fewer than normal in a 40H rim.

jackbombay

Eeeekkkkk!!!!!

Do you have an early FM with the desirable early ball cup?

desconhecido 

The only rims I know of in 40 for 700c are Sun Rhyno Lite and Velocity Dyad (and other Velocity offerrings). I've built wheels with both. Seems that the 590 CR18 with 40 is no longer which is a great loss for lovers of Raleigh Sports bikes and similar as there is no substitute as far as I know. Well, SJS offers what looks like a house brand single wall alloy rim with 40h in 590 mm, but I've never seen one or heard of how they are.

Not so many years ago, you could get 700c CR18s in 40h.

Oh, for the good old days.

JaccoW

Not sure, disassembly is due for some time later this year:

jackbombay

Nice restoration on that 4 speed shifter!


Just to put some more info on this wheel build in this thread, you calculate your spokes for a 32 hole hub and rims, then do the addition/subtraction noted above. For the 700c rim I used (ERD of 611) with a Sturmey hub my spoke lengths were 290 and 296, 16 of each. I did add this info to the original post too.