2-cross versus 3-cross

[jorgemartin]

I've asked my local spoke supplier to provide me with some spokes for a new 20 inch wheel.
The set up is a dynohub and 36 spokes in 3 cross lacing pattern
He says because a dynamo hub has a larger diameter, I should be using a 2 cross lacing pattern
Isn't this going to result in a weaker wheel?
Should I insist in the 3 crosses? Is there a lot of wisdom in a 2 cross dynohub wheel?
Any ideas?

 

[andrew_s]

2 cross will be right.
If you use 3 cross with a big hub and small rim, the spokes reach the rim at an angle, and you tend to find that they have a tendency to break where they enter the nipple (which is square on to the rim). This is even more of a nuisance than the common snapped off spoke head, as to fit a new spoke you've got to take the rim tape off and fit a new nipple that's not full of the end of the dead spoke.
It is possible to put a permanent bend in the spoke just above the threads to avoid the problem, but it's a bit of a pain getting the bend right.

 

[Christopher]

I have a 32 spoke 700c wheel laced 2x. TBH I can't tell the difference between when the same hub was laced 3x and the wheel is strong enough for CX racing.
I think the real difference comes when a wheel is raced 1x or radial, but you don't have that. Anyway a 20" wheel is going to be very strong anyway so I don't think there will be any difference between 2x and 3x lacing in your wheel

 

[jorgemartin]

If I understand correctly big hub, small rim, 3-cross=danger?
I also have an SRAM dualdrive (67 mm flange) hub which I want to build with a 20 inch (rear) wheel. I was thinking of using 3-cross here but perhaps this is not a good idea? Are the spokes going to break?