Abbey lacing stands are back in stock and improved!
December 21, 2011 7 Comments
[Note: this is #14 of a series of 20]
You have undoubtedly noticed, and I mentioned in tip #4, that spokes do not exactly conform to their path once laced into a wheel. This is especially true at the hub. With higher quality hubs and spokes, the spoke elbow seems incomplete, resulting in a bowed shape before full tension is applied.
This bowing is, indeed, owed to incomplete elbows. Better spokes, those destined for high end builds, have short elbows and a more open angle like 105° rather than 90°. Better hubs also have smaller spoke hole diameter and thicker flanges. Consequently, the spoke can be laced through the hub but it doesn't fall down to the correct angle towards the rim. Why?
It turns out that bending a spoke after it has been laced maximizes contact with the hub and significantly increases fatigue life. Spokes that drop easily into holes and swing to correct angle without resistance end up with less support. At the same time, spokes on the inside of the non-drive rear hub flange do not need much elbow length or angle. You see, spoke positions in a pair of wheels vary as to exit angle.
For these non-drive side spokes, the incomplete elbow is a perfect fit. Were the elbow larger, it might become opened a bit as tension is applied, which reduces fatigue resistance. Since we're happy about these miss fits, because they extend spoke life, what technique is appropriate to make sure the fit is perfect?
Some builders favor hitting the spoke with a hammer, close to the elbow. I see three problems. One, there's no striking elbows on the flange inside surface and there's a chance some of those spokes could use straightening. Second, few hub makers design flanges to resist hammer blows. Spare those hubs! Third, hitting a wheel 16 or more times with a hammer is invitation for a miss. Leave hammers to carpenters.
The way to quickly and consistently bend incomplete elbows into perfect hub contact is a lever.
Insert a round rod, like a big Phillips screwdriver blade, or handy piece of scrap steel, into the large triangle defined by the cross pattern. Angle your rod so it bends an outside and an inside elbow at the same time. It will be obvious which way to apply pressure.
Go around the wheel giving a forceful push to each elbow. If you push too hard, no worry. The spoke is not seriously harmed. Ease up. No need to struggle and unbend the over-corrected spoke. Do this setting procedure when the wheel is laced but still has low tension. Notice how loose the wheel becomes. The old school practice of letting tension do the elbow setting is inadequate because spoke metal needs an over correction, like any steel, so tension may appear to straighten the spoke but it still has a memory of its original shape. As you ride and tensions vary, your spoke will be returning to its shape, constant flexing, eventually leading to breakage.
I'm glad to know you won't be ignoring elbow shape and spoke path. These geometries are fundamental to wheel function and you need to be making optimal adjustments so your wheels are as perfect as they can be.
November 02, 2021
i have used this technique on a number of builds but sometime worry that I’m overdoing it with correcting the spoke line. The problem has been with doubled butted spokes where I find that the spoke tend to give more on the butted part of the bow rather than at the flange where I want the spoke elbow to be embedded nice and tight with the hub. I’m wondering if using a larger screwdriver or rod is important here? i.e. to create more surface contact with the bow so the spoke bends more uniformly and less so at the butted section? I saw in Gerd Schraner “Mastering the wheel” dvd the he used a special tool that cupped the spoke around the bow. He then hit with a small ball and peen hammer to straighten it when the wheel was at optimal tension. It looked kind of effective as a method not something you can buy from the DT catalog. At the end of the day, I just want to get spoke lines nice and straight but I’m having less luck with double butted (sapim) spokes.
November 02, 2021
Hi Mike,
I don't know of any hubs whose flanges are designed for the blows that might come from a 24oz hammer and steel punch. Without extensive testing, I wouldn't assume such punching carries no risk of hub damage. Most hub makers these days are very concerned with weight and cutting every corner they can find. So, however well punch-setting might seem, you almost need to be the
November 02, 2021
Great blog, and wonderful article. I'm so happy you're getting along with the tips on wheel building.
I have a question: what are your thoughts on using a punch with a concave tip to set the spoke head in the flange, when the elbow seems to be a bit too short for the width of the flange?
I remember building a set of wheels with Phil Wood spokes and some Campy hubs
November 02, 2021
Great blog, and wonderful article. I'm so happy you're getting along with the tips on wheel building.
I have a question: what are your thoughts on using a punch with a concave tip to set the spoke head in the flange, when the elbow seems to be a bit too short for the width of the flange?
I remember building a set of wheels with Phil Wood spokes and some Campy hubs
November 02, 2021
Thanks a lot for the tips! I've learned a lot from them.
Cedric
November 02, 2021
Building a wheel yesterday and using this same technique, someone who’s been around bikes a long time saw me and said he’d never seen that done to spokes during a build. Coincidentally interesting you posted this today. Six more to go. Thoroughly enjoying this series.
Mike
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Tim Cupery
November 02, 2021
Ric, thanks for all your articles. I’ve been seating spokes this way whenever I build wheels. But I more frequently true and optimize tension on machine-built wheels for friends’ bikes. Reading this made me wonder if there is potential value (and little potential risk) to lever-seating spokes on a wheel that’s already seen some miles, and never had spokes seated when built. Guessing not worth the time to take spoke tension down, set spokes, and build tension back up, plus there may be a “do no harm” reason to avoid this practice. But was curious as to your thoughts.