Spoke length dilemma
I've now decided to get a front disc brake for my SS commuter bike (has V-brakes now), but I have no front wheel with disc mounts, so I have to build one.
36-h Deore 6-bolt hub (HB-M475) and a 36-h XM317 (non-disc) rim, 3-cross.
Spocalc has worked fine for me for the previous four wheels I've built, so I trust its calculations, but this time I have a bit of a problem.
The hub isn't symmetrical because of the disc mount, so the spoke lenghts are naturally different for left and right sides. Left (disc) side comes out at 255.5 mm and right side at 257 mm. The spokes (Alpine III) are only sold in 2 mm-increments. In this case 254, 256 and 258 mm.
Would it be a bad idea to go with 256 mm for both sides? If yes, what would be better?
Non Tribuo Anus Rodentum and off to the next adventure (RIP)
You shouldn't have a problem, but you might consider the 254 on the 255.5 side. I personally like to spoke shorter rather than longer.
I've operated on the theory that plus or minus 1mm would be adequate and I've never had a problem.
I use Spocalc and on my first wheelset rounded up on the drive side because it equaled my front spoke length (I could buy 'em cheaper, yea!). Some of those DS spokes bottomed out at full tension. It still worked but I've rounded down ever since.
I'll go 256 right and 254 left then.