I am in the process of getting a new rear wheel. The rim and hub have been ordered but I am a bit stuck at spokes - I am not sure how to calculate the required length. I am also unsure of the differences between different lacing patterns.

First of all, here are the hub and rim I have ordered (48-hole models):

http://www.wiggle.co.uk/p/cycle/7/Ha...ub/5360042432/

http://www.bike-mailorder.de/shop/Si...ch::20270.html

I plan on ordering DT Alpine III spokes to match these parts but what length do I need? Does it depend on the lacing pattern?

I am not sure what lacing pattern to use. Are there any objective differences between them? I once read a study on the internet with lots of numbers and graphs but I did not understand any of it

In any case, please recommend me a spoke lacing pattern and tell me how to determine what length spokes I need. Can the length be determined based on the info available on the web about these components? Or do I need to measure them when they arrive?

I stuck some numbers into the DT Swiss spoke calculator on the web but it wanted some figures which I did not have (I believe it wanted rim inner diameter - can this be determined somehow? I did not see any such number on the shop website where I got the rim; there is an "Aero profile length", though - is this useful?).

I have recently discovered that spokes are far more expensive than I figured for small pieces of metal, so I would rather not buy the wrong size Unfortunately, local shops only have straight-gauge spokes available, so I need to order online and can't leave it to the shop that will actually build up the wheel.