Wheelbuilding assistance please
 

A few questions as I haven't built a set in a while...

Good online spoke calculator with a modern rim/hub database?
Seems the DT Swiss one now restricts you to DT brand hubs whereas they used to have pretty much everything. Really, I'm not at all amused by that. :crash:

Next, I can't find much advice on running wide rims. Is there a magic ratio? Sheldon, Schwalbe, Sun, etc all have varying advice but suggest my idea is ok.

I'd like to build two 26" wheelsets with 31 and 34 mm Sun rims. They would probably have ~2.1" tires but the ability to run tires as narrow as 1.5" would be nice, if not necessary. I've decided on robust DH rims since the potholes are cracking my nice, light, DT rear rim (it was a stretch under my Clydesdale caboose).

Any help appreciated.

Search for "SpoCalc". It's a .xls (spreadsheet) file with most rim and hub combinations available. I have a link at home for another web-based program that a BF member created based on info from various calculators. I still find SpoCalc easier to use but the web-based program has more rim and hub info. You might be able to find it by searching or I can post the link when I get home. SpoCalc could use an update.

If Sheldon, Schwalbe, and Sun all agree that your tire and rim combinations will work, I'd feel pretty secure with the choice.

I use spokecalc and the DT calculator as a check. For DT, you can use any hub you would like... just put "user defined" in the box and fill in the hub dimensions manually. I don't rely on databases for dimensions. Either get it from the manufacturer, a trusted source, or just measure it yourself.

Can't help you much on the subject of rim width...

I just noticed that limited database in the DT calculator the other day...they just being difficult for the competition? Joe--was EDD the other calculator? http://lenni.info/edd/

RogerM's site has a calculator, too http://www.wheelpro.co.uk/wheelbuilding/book.php

Really, I'm trying to be lazy. The DT calculator WAS great when it had the database. Seems SpokeCalc and most others all use the same antiquated database of hubs.

As to rim width, none of the sources are definitive, rather, they allow one to very reasonably infer I'm in the ballpark. Seems there is plenty of info about going narrower, not wider with rims.

You don't need a database, learn how to measure hubs and rims for yourself. It's easy and in the long run more reliable.

As far as rim width goes I prefer the inner rim width to be between 1/2 and 3/4 of the overall tire width. That's only a guideline, and there's lots of wiggle room. One way is to consider a profile of the mounted tire in cross section. It should resemble an Omega, not an upside down U.

Perhaps the simplest spoke-calculator out there - take a look:

http://lenni.info/edd/

be careful with rim width and brake compatibility. Make sure that the posts on the frame you're intending to build these wheels for will allow your brakes to work well with wide rims.

Disc brakes.

EDD is the one I use as well.