Spoke threads

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You may have noticed that we build our standard alloy wheels with round spokes (Sapim Laser and D-Light) versus bladed spokes. Having studied the aerodynamics of the question, we came to the conclusion that for alloy wheels, where by definition you are not looking for every last bit of aerodynamic speed, the logical default choice was to offer the significant cost savings of round spokes. Of course you can get bladed spokes in alloys as a custom option, but for standard builds we feel that round spokes make more sense. Since it's always worth repeating, Lasers and CX Rays start life as the same piece of wire and weigh the same. CX Rays have very slightly better cross-sectional tensile strength thanks to the ovalizing process, but we've never seen either break in tension, and the weight between the two is the same.

A HUGE part of the current prevalence of bladed spokes is the ease of use they offer the builder. You simply use your handy dandy spoke holder to prevent the spoke from twisting as you turn the nipple on the spoke, and that's it. No wind up. It also offers a lot of precise control, so you can make super small adjustments and build wheels to really high resolution. 

Bladed spoke holders make life easy for wheel buildersOf course, we don't think it's a particularly good value to ask you to spend a lot of money to make our lives easier. We know well enough that wheels with thin, potentially twisty, round spokes can be built to the resolution that wheels with bladed spokes can - it's just a bit tougher and more time consuming to do it. Which if you've paid attention to anything at all that we've done, is just the kind of challenge we love. The question then becomes "how do you manage the spoke/nipple interface in order to get near-perfect thread engagement, while allowing the spoke tension to be adjusted with as high a resolution as you can get with bladed spokes?" And we spent, oh... about a half a year working on it. 

I should quickly explain that some time in 2015, we started noticing that general thread engagement, across all the spokes we use, got a bit troublesome. We talked to Sapim, we tested different spokes, we tested different nipples, we talked to other builders, and we were nearly at a loss. The one bright spot was that we came across Wheelsmith's brass nipples. Wheelsmith plates their black brass nipples, as opposed to the oxide coating that Sapim and DT use on their brass nipples, and as opposed to the anodizing that's on aluminum nipples. The plating surface has much much less friction than either oxide coating or anodizing. Our frustrations with oxide coatings were what made us dump brass nipples in favor of all aluminum a couple of years ago. 

Plus, they look really coolThis was a big imporovement, but alas - we wanted more. Some of the rabbit holes you jump down when you're chasing stuff like this are pretty crazy. For example, I somehow wound up on a bunch of gun owner's forums, as they seem to be as obsessed with the kind of stuff we were chasing as we were. That led us to try this toilet cleaner called The Works (no, I am not kidding) as a spoke thread cleaner. This stuff is so strong that if you have some in a jar and you leave that jar, open, in close proximity to a hub while you go eat a sandwich, it will discolor the anodizing on the hub shell. Don't ask me how I know that. But, as the gun owners said it would, it removes oxide coating from steel with shocking ease. I should clarify that this stuff scared us so much that we never used it for anything outside of the tests. It only cleans the shop's toilet these days (and we're even a little scared of it for that). 

This stuff is NO jokeThrough this time, we were using a Hozan spoke roller to chase the threads of every spoke we used. Pete, who is an absolute genius at figuring this kind of thing out, figured out how to knock the process down to a few seconds per spoke. It helped, but again, it wasn't nirvana. A confluence of things, including Sapim often being out of stock on one of our critical spoke lengths, plus our desire to have more precise spoke lengths than what spoke makers offer as stock, caused us to invest in a Phil Wood spoke machine. We found one on eBay, bought it, took a while to learn to get the most out of it, had Leroy-the-world's-leading-spoke-genius dial it completely in for us, and we went from sorta-kinda being close, to being hot on the trail of thread perfection.

Expensive, and so completely worth itAmong the benefits of the Phil machine is that you can buy spoke blanks instead of cut and threaded spokes. They cost the same, but you can more easily hit a (pretty modest, honestly) volume discount much more quickly when you buy blanks - instead of buying a couple hundred of this length and a few hundred of that, we order much bigger volumes of blanks. This really allowed us to start doing the drive/disc side D-Light thing, which is a nice benefit to how the wheels work. Keeping a dozen sizes of a few different types of spoke on hand would have been onerous and prohibitively expensive. Now, we just keep a lot of a few different sizes and type of blanks on hand, and cut and thread to suit. Since our spoke lengths are so clustered in a few length ranges, this works exceptionally well, and we are able to achieve spoke length precision that we previously couldn't.

Part of having Leroy dial us in with the spoke roller (and spoke threads are rolled, not cut - topic for a completely different day) is that we now get deeper, cleaner, and more consistent threads. 

Stock spoke with BARE minimum thread depth - sad clownThe threads of Bad Bad Leroy Brown make for a very happy clownAnd yet, there's more. We knew we were close, but we knew there was still some juice left to squeeze. So we started experimenting with different post-threading treatments to ensure that the threads were both mechanically and chemically as prepared as they could be going into lacing. We also sought the ideal thread prep for lubricating the threads during assembly, and protecting the interface through the life of the wheel. These steps actually shocked us in how much improvement they offered. 

So what's in the bucket? Of course, attacking this issue for round spokes has had immediate spillover benefit to the CX Rays that we use, as we prep all spokes the same way. We've gone from struggling to get the resolution we were after with round spokes, all the way to being able to make micro little adjustment to a drive side spoke under full load, with barely a hint of spoke twist. And that helps us build ever better wheels. 


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  • Hans on

    Ah, brilliant. Yeah, I used to just "feel" the windup, and that works just fine for the thicker spokes, but I had trouble managing the windup by feel with the really thin spokes (Lasers) since they wind so much. Having a solution to eliminate (or greatly reduce) windup altogether sounds wonderful. Building with CX Rays does feel so nice, so I do still treat myself to that for my own [road] wheels, but really hard to justify the cost otherwise, I agree.It always struck me as odd that Lasers and CX-Rays start off as the same spoke yet Sapim advises against using Lasers in disc-brake wheels. I guess that extra tensile strength made enough difference for them to recommend CX ray for disc brakes? I've built disc-brake wheels with Lasers, as I imagine many have, though when I could get affordable D-Light spokes, I just switched to using those (or CX Rays, if road & deep rims).



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