Bought Dynamo Hub - where to begin?

[albion]

So my Shimano Deore LX Dynamo Front Hub has arrived. (to be mainly a smartphone GPS charger)

My hybrid's front wheel has 24 spokes so I have bought the 36 hole but I'm slightly baffled on how to measure spoke lengths. Obviously on the hub its a fill 2 miss 1 scenario but measuring seems weird.
At the Rim spoke are in groups of two very approximately 4cm apart with a gap of a good 11 cm between each group.

I've refitted a full set of drive side spokes but never built a wheel from scratch so am not sure which way to go,

 

[albion]

To complicate matters it is the disc brake compatible version DH-T665 so I also might have to allow for dish.

 

[Gerry Attrick]

Voila: http://www.wheelpro.co.uk/spokecalc/

 

[albion]

OK so hub flange diameter sounds simple but what is flange distance measured on?Rim diameter I'm guessing means 622mm.Rim offset. Is that how far a spoke is from centre of the rim?It also concerns me that the 24 holes in my RIM are certainly not equidistant




edit - am now also reading this

http://lenni.info/edd/howtomeasure

 

[Gerry Attrick]

If you press the "Help" button on the page I linked you to, you should find your answers.

 

[albion]

I seem to get this strange data at the bottom.


You must ensure the hub manufacturer allows radial spoking of this hub, many manufacturers do not.Hub : Edit hub name
Rim : Edit rim name
Wheel geometry
Wheel type : Front normal
Hub diameters : Left = 70 Right = 70
Flange distance : Left = 26 Right = 23
Rim diameter : 583

24 Spokes

**********************************

Left Right
R 1x 2x 3x 4x R 1x 2x 3x 4x
256.4 261.6 275.4 293.3 310.1 256.1 261.3 275.2 293.0 309.9

 

[albion]

I now get a feeling that I should use the existing built normal wheel plus a piece of string to measure the distance change between hubs.

The 'non equidistant at the rim' spoke pattern also concerns me.

 

[the snail]

Have you tried the manufacturer websites to get the measurements? Alternatively you might find an online spoke length calculator with the rim/hub details on a database. Measuring with a piece of string doesn't sound very accurate. At a guess 'non equidistant' refers to a new-fangled rim where the spokes aren't evenly spaced. Good luck!

 

[Nebulous]

So my Shimano Deore LX Dynamo Front Hub has arrived. (to be mainly a smartphone GPS charger)

You as well eh?

It's amazing the lengths I will go to to avoid missing a bargain in the sales!

There is this real risk that my too good to miss buy may turn into hundreds of pounds worth of touring bike.

Anyway if you work anything out I'd be grateful if you could let us know. I'm only just discovering that wheels don't need to come from a bike shop. I'll probably go for 700cc rims - but what else I need I'm not sure. I kind of think that as I'm building a big hub into my wheel I might as well go for the set and go for hub gears at the back.

 

[Night Train]

I'm not sure a standard spoke length calculator would work for you.

The problem will be the mismatch between hub and rim hole count. If your hub had 24 holes then they would be spaced further apart from each other then they are with 36.
So when you use a calculator it will assume that you are using 12 equidistant holes on each side of the hub instead of your 'use 2, miss1' spacing.

The end result will be that, for each side, you will have at least 2 different spoke lengths so possibly 4 different lengths to allow for any offset.

 

[albion]

There is that conundrum too. I'm half inclined to just buy new RIMS and make my first ever wheels.



Yes, sale prices are persuasive though I am unsure how they will cope with a possible 7000 miles a year.
Two were close to the price of one non disc compatible dynamo. However my v-brakes work great so I'm certainly not tempted by discs.

 

[Night Train]

If you get a new rim it will make the wheel build a lot easier, especially if it is your first one.

You could get in touch with Spandex (Your Spokes) as he builds wheels. He can probably post you a rim and spokes.

I have built three wheels recently, two with new spokes and rims onto SA drum brake hubs and one rim replacement.
That's the first time in just over 30 years since my previous wheel building.

 

[PpPete]

This is a good guide on measuring here (slightly easier to measure rim ERD this way than the way on the Edd site)

If you do choose to go 2 holes and miss 1 (which is NOT recommended) you can calculate it as a 24 spoke and round up. The extra length at the hub between 24 optimally placed holes around the hub and what you have is going to fairly minimal.

Incidentally I'd recommend that downloadable book from the wheelpro site as being the best (as in clearest to understand for a beginner) guide to wheel building.

 

[John the Monkey]

Incidentally I'd recommend that downloadable book from the wheelpro site as being the best (as in clearest to understand for a beginner) guide to wheel building.

Seconded. The plans for building your own truing jig &c are excellent too.

 

[yello]

If you do choose to go 2 holes and miss 1 (which is NOT recommended) you can calculate it as a 24 spoke and round up.

I'm glad somebody has said this because, in honesty, it was my first thought when I read the OP. It's certainly not something I would have thought of doing, let's put it that way. Personally, I would be looking for another rim.

When I bought my dynohub (Shimano something or other, a replacement for an older model that died on me), I ordered the wrong one and ended up with a 32 hole hub for my 36 rim. Fortunately, I had a spare 32 hole rim so I laced that up with the new dynohub. Then I bought a cheap NOS campag 36 hub and built that one up. So now I have 2 wheels and only use the dynohub one when I'll need it. Hopefully, it'll extend the life of the dynohub!