In the previous post, we discussed what constitutes a true wheel. Let's pick it up from there...
First, the one thing EVERYONE does when they get new wheels is give them a hard spin, take the hub ends in hand, hold them out, and carefully eye whether or not the wheels run straight. It's a habit that people have, and I've got plenty of weird ones myself, but this doesn't tell you much of anything. It's probably most useful at telling you if your hub bearings are in good shape. Beyond that, your hands move way too much to see anything for real. Instead, one very simple thing to do when you get a new wheel is to pluck the spokes and note the tone. All the spokes in a front rim brake wheel should sound just about the same, and all the spokes in a side of a dished wheel should sound about the same. The thinner the spoke, the higher the tone. There will be sharps and flats, for sure - tone is a proxy for tension equivalence, only a strain gauge could tell you the actual tension differences. Often times the tension meter will say two spokes are spot on the same tension but they have slightly different tones. Guitar players will understand this. But if you pluck the spokes and it sounds like the them from "Close Encounters," the tensions likely aren't very equal.
Then, squeeze parallel-ish spokes together. If the tone drops, then the spokes weren't adequately stress relieved. Semantics aside (and wheel geeks will argue them for days), the important thing for your wheel builder to have done is to have gotten the wheels to a point where only a catastrophic stress would affect a spoke's tension. This is one of the big differences between an average wheel builder and a good one. Also, be aware that when you put a clincher tire on, even before you inflate it, spoke tension is going to drop a little bit, and there's nothing that can be done about that. Good wheel builders take this into account. It also sounds like more has dropped than actually has, because the tire acts like a mute. Trumpet players will understand this.
There are a bunch of different tools and fixtures that help us achieve a wheel that is centered, round, and straight, and has the best chance of staying that way forever. I'll be coy about them because we've spent a lot of time and money developing the tools and the expertise to use them. However, one of yesterday's commenters has a site that has some great info if you'd like to learn. Even if you leave the wheel building to others (which we won't mind at all), knowing more is better.
So what about machine built versus hand built wheels? Here are a few videos that show elements of automated wheel building. You'll notice that the second video straight up says that high end wheels need to be built by hand - and this is a company that sells capital equipment for machine building wheels (as well as a nice setup for helping to hand build wheels). In the broadest strokes, the machines are fairly capable, but they have a few critical deficiencies. First, they can only sense big errors. Second, they absolutely can not detect spoke windup - this is why so many new machine-built wheels ping and pop on first use. There are others but I'm running long as is.
A machine would not even be capable of building a set of Nimbus Ti wheels, because the spokes we use are too thin, and the maching couldn't manage the windup (windup is simply when the spoke twists on its axis instead of having spoke engagement - our approach to that is a whole blog in itself). So why use thin spokes? They're stronger for their weight (and often just plain stronger), they're way lighter, and they last longer because of their ability to absorb shock. The initative to build with generic bladed spokes (and don't kid yourselves, these spokes are not the equivalent of Sapim CX Rays or DT Aerolites in any dimension), which has created a bit of a fashion that I think is waning but exists, was really to make both machine and hand building easier - preventing windup with a rectangular spoke is easy because you can simply hold the spoke.
The other huge thing is the benefit of the human machine. A good wheel builder keenly observes how the wheel acts and responds during the build. Good rims of a type are similar to one another, but no two rims are the same. The process of building a wheel is a constant progression of action -> observation -> decision -> response. Your hands and shoulders get worked over after a big day of wheel building, but what really gets fried is your focus. Your synapses are going mad all day. And through this whole process, the good wheel builder does a huge amount of QC and troubleshooting, to a degree that way surpasses what a machine can do.
I'm not quite done with the topic but your focus is probably shot from my having gone too long, and I have to get to the business of building wheels. Thanks for reading.
amazed at how much goes into wheels on a bike. just found your site, via bike forum reference in the bike mechanics section.
Too long? Not a chance. This is fantastic information. Knowledge is Power.
Having built the set of wheels on my road bike (AT my LBS with the lead mechanic over my shoulder guiding me), I can attest to the amount of work and concentration that goes into hand-building a set of wheels. I absolutely loved the experience and would love to build more, as you just hone in on what you're doing and everything else disappears. I have mad respect for those that build wheels all day, every day. This is an art that only the human can perfect!