Hubs

So the first step to building wheels is figuring out which hubs to use.  This turns out to be a matter of no small consequence for your budget.  After much anguish and poring through incomprehensible part names like M285 Saint,  105 5800, SRAM XO...  I came away with a few insights.

First, more expensive hubs are not necessarily better for a touring bike - often you're paying for lighter weight, which might be better for racing, but less durable for touring.  It seems like the best bet for a touring bike is to stick with mountain bike hubs.

Second, part numbers change on a regular basis and it's actually rather difficult to figure out which of a manufacturer's offerings are the latest, and which are leftover stock from last year.  At least I couldn't find anything to tell me which was which.

Third, not being a mountain bike geek, I wasn't aware that there's a whole new hollow axle - or "through axle" or "thru axle" that's considered the latest and greatest thing.  Fortunately, you've got to decide you want hollow axles when you buy your frame as they don't fit on the standard QR (quick release) mounts that have been around for decades.  Since the Surly frame I've ordered has standard QR mountings, I don't have to even think about the choice.

Four - something fairly obvious, but perhaps worth noting - if you're fitting up a bike with disc brakes, then you've got to have hubs designed to mount the discs.  There is an ISO standard that uses 6 bolts to mount the brake rotor.  Shimano has a proprietary standard they call "Centerlock".  No doubt there are other proprietary systems as well.

It seems like the "go-to" hubs for most touring bikes are Shimano; possibly because they have a wide range of capabilities and prices.  The folks at TravellingTwo have been using Shimano Deore LX which are inexpensive ($15 to $25) and supposedly really sturdy. It's not clear that Shimano is still using the LX designator for these. Although you can still find Deore LX for sale on the web, Shimano doesn't have an LX on any hubs in the mountain bike section of their web site. It looks to me like the have a "Deore" without any fancy letters (model FH-M615), then the SLX and Deore XT as the next two levels up (XTR is apparently the top - but is way out of my budget).

At the end of a lot of reading and research,  I still didn't (and don't) feel like I had a good idea of what hubs would be best.  As I'm building on a Surly Disc Trucker frame, I decided to take a cue from their build with the older Shimano M756.  That hub was superseded by the Shimano M785, and now by the M8000.  Anyway, after much indecision, I found a good deal at PricePoint.com and got the XT M8000 hubs at $50 for the front and $65 for the rear.  The M785 are still available online, and I could have gotten those for about $35/$50 for front/rear, but I decided to splurge and go with the latest.

A possible drawback to the M8000 is that it is only (as of Oct 2015) available in a 32 hole configuration (i.e. for 32 spokes) and most touring bikers seem to prefer 36 hole hubs.  Only time will tell if I've made a mistake.