Spoke wrenches, nipple driver, dishing tool, truing stand... key tools for wheelbuilding. But one of the best tools for wheelbuilding isn't at your bench, it's the online spoke calculator FreeSpoke.
Selecting wheel components can be tricky enough, but actually calculating the proper spoke length is an arcane black art. Freespoke is the best calculator I've found so far, and for each of my whopping four wheel builds it's proven informative and accurate.
There are other calculators - why Freespoke?
- It is accurate*
- It has a decent rim and hub database (some calculators have none, or are brand-specific)
- It is easy to enter data from your chosen components when they aren't in the database
- It reports spoke tension and has a nice visual on spoke configuration.
The last item is more of an advanced topic, but worth noting. Rear wheels, and most disc wheels, result in a slight offset of the hub flange on one side. Look at the drive-side of your rear wheel sometime and you'll see those spokes are shorter than the non-drive side, to make room for the freehub.
This results in unequal tension of the spokes. It's natural and fully normal. It's also something rim manufacturers are starting to compensate for with off-center rims. Want to see improvements between a standard Velocity A23, or a Velocity Off-Center A23? Run them through the calculator.
Geeky? Sure. But if you are building your own wheels, you've already crossed far into geek territory. A great explanation of off-center physics can be found in this video explaining why the OC A23 is superior to standard.
Freespoke is the creation of Karl Stoerzinger who wrenches for the great Freewheel bike shop in Minneapolis. Thanks Karl!
* Limited data: First two wheels I built, used multiple calculators with different answers, and bought the wrong spoke size. Next four wheels - built with Freespoke's help, and correct length each time.