Spoke length calculation help

[Drizzt321]

So I'm using 2 different spoke length calculators, http://www.ebikes.ca/tools/spoke-calc.html and the Sheldon Brown spocalc http://sheldonbrown.com/rinard/spocalc.htm and they are giving me close, but different numbers. I've got the MXUS XF07 hub motor, and took my measurements off the presets on http://www.ebikes.ca/tools/spoke-calc.html. Doing 1 cross, elbow in I get 202.2mm and elbow out I get 203.2mm from that one. Using spocalc I get 203.7mm (I'm guessing elbow out?).

So, they are close, but are they close enough to say 203mm is good? Or 204mm? This is a first wheel build (prebuilt all the other times), so what would you guys suggest? I'm going to get the Sapim Strong 13ga elbow 14ga spokes. And does nipple length matter so much? 12mm? 14mm?

 

[MadRhino]

Various nipple brand and size does change a tad the max spoke length you can use before it goes through. It is irrelevant with double wall rims, but you don't want spoke tips pointing out of the nipple heads in a single wall rim. Go for 202mm, and use the longest nipples if you can, because a hub motor wheel does require more spoke tension than a regular wheel.

 

[Drunkskunk]

Spoke calculators round to the nearest tenth of a mm, but for ordering spokes, you round to the nearest mm. And it's fine to be 1 or 2 mm off. No worries. I'd call that 203mm.

12mm nips are fine, but longer give more surface area for gripping the spoke threads, more surface for the wrench to grip, and can be taken to higher tension in some cases. You can also be up to an extra 2mm too short on your spoke calcs, with a 14mm nip vs a 12mm nip. Whats far more important is that you use brass instead of alloy.

 

[Drizzt321]

It's double walled rim, so less worried about the the spoke tips poking through a few mm. I'll go for the 203mm then, sorta split the difference.

I'll go for the slightly longer nips, and that way there will be some room to play. I'm actually going to have a bike shop lace it up, since I don't have any experience in properly truing a wheel or making sure the tension is good. Thanks guys!

 

[docw009]

Driztt321, where are you getting your spokes?

I want to be lacing up a Bafang SWXH and the spoke calculator gives me 201-202 mm. I was going to buy 13G "e-bike" spokes off ebay, but maybe I should go with 14mm, as the wheel builders here like that.

 

[Drizzt321]

Sapim makes spokes 13ga at the elbow, 14 GA rest of the spoke. Sapim Strong I think they're called.

To answer where I'm buying them from, http://wheelbuilder.com/ although you can get them elsewhere such as http://ebikes.ca/. Mostly I'm buying through them because they're very close to me so shipping times with the cheapest option is very fast.

 

[docw009]

Thanks, Drizzt321. A local shop in Chicago sells Saphim Strong on ebay. Next time, I'll just call and pick them up.

As you note, they are 14mm at the ends, with a 13mm elbow. I decided to get washers for them after seeing how the 2.3mm elbows fit in the 3mm hub holes.

BTW, I realized I'm 2 years behind on those Salvatore tales.