To the Point - DT Swiss Talks Spokes
DT Swiss did not become the world’s leading spoke maker overnight. It has been manufacturing wire products, and forging and shaping metal before electricity powered factories. Its first machinery was powered by water wheels and until relatively recent times, the DT Swiss factory in Biel, Switzerland, stood on the same foundations at the foot of the mountain stream that powered the original plant. Now the site is being restored as a natural area and DT Swiss has moved nearby to a new location. DT Swiss also has manufacturing plants in Europe, Asia and North America that produce wheels, hubs, suspension products and, of course, stainless steel spokes – millions of them. This week’s ‘To the Point’ documents some of the intricacies of their spoke manufacturing process.
![DT Swiss spokes in bin]()
Spoke Primer:
DT Swiss says that its spokes are forged. Is that a different process than drawing wire to size?
![Rotary Swaging machine patent drawing]()
Reduced aerodynamic drag is not a factor for off road cycling, so why do mountain bike wheels sometimes use bladed spokes?
![DT Swiss bladed spokes]()
What kind of stainless steel is used to make DT Swiss spokes?
Is there any sort of heat treat process involved in the making of a spoke?
![DT Swiss aluminum nipple collection]()
What is the difference in strength between aluminum and brass spoke nipples?
![DT Swiss Pro Lock nipples]()
How are the threads applied to the spokes?
![DT Swiss spoke cutting and threading machine]()
Is there any significant loss in strength between a J-bend or a straight-pull spoke in real life?
![DT Swiss Competition spoke]()
Is a double-threaded straight-pull spoke stronger than one with a formed head on one end?
![DTSwiss Tricon front wheel]()
What is the difference in thickness between the original coiled wire and the finished spoke?
Is butting a spoke done only to save weight, or are there other benefits?
![Black and white spokes DT Swiss]()
What is the typical tensile breaking strength of a DT Swiss spoke?
![DT Swiss factory]()
How many spokes will DT Swiss make in 2013?
More about DT Swiss
A batch of freshly made DT Swiss spokes leaves the threading machine and will soon be on its way to join a wheel. (DT Swiss photo)
Spoke Primer:
Gauge: refers to US/British standards for the thickness of wire. Most stainless steel spokes are made and butted to one or a combination of 14, 15, or 16-gauge wire thicknesses (2.0mm, 1.8mm and 1.6mm). More about gauges
Straight gauge: wire, or a spoke that is of one constant diameter throughout its length.
Butted spoke: a spoke manufactured with one or more thicknesses across its length, thicker near the ends and thinnest in the center span.
Bladed spoke a spoke that has been ovalized or flattened across its span.
Drawing: pulling a larger-diameter wire through a smaller hole in a special ‘die’ to create a longer, smaller-diameter length of wire. Tubing is also made using the drawing technique.
Forging: squeezing metal in one or a number of steps into a smaller shape creates a more dense condition of the metal and helps to align its grain structure in a more desirable direction for a specific application. Spokes are forged using a radial forging (also, rotary swaging) technique.
J-bend: the standard spoke head is bent at 90-degrees and looks like the letter ‘J.’
Straight-pull spoke: spokes that have no bend at the flared head, or in the case of DT Swiss Tricon wheels, spokes that are threaded at both ends. Straight-pull spokes require dedicated hubs.
Straight gauge: wire, or a spoke that is of one constant diameter throughout its length.
Butted spoke: a spoke manufactured with one or more thicknesses across its length, thicker near the ends and thinnest in the center span.
Bladed spoke a spoke that has been ovalized or flattened across its span.
Drawing: pulling a larger-diameter wire through a smaller hole in a special ‘die’ to create a longer, smaller-diameter length of wire. Tubing is also made using the drawing technique.
Forging: squeezing metal in one or a number of steps into a smaller shape creates a more dense condition of the metal and helps to align its grain structure in a more desirable direction for a specific application. Spokes are forged using a radial forging (also, rotary swaging) technique.
J-bend: the standard spoke head is bent at 90-degrees and looks like the letter ‘J.’
Straight-pull spoke: spokes that have no bend at the flared head, or in the case of DT Swiss Tricon wheels, spokes that are threaded at both ends. Straight-pull spokes require dedicated hubs.
DT Swiss says that its spokes are forged. Is that a different process than drawing wire to size?All DT Swiss spokes are forged into the diameters and shapes needed to suit the desired application(s). It's actually more of a complex process than you would think. The only "drawing" process that a spoke ever goes through is at the factory when it isn't even a spoke at all. The molten mix of metals is drawn into a constant diameter of wire and then forged into straight-gauge spools of wire. This wire forms the basis of all spokes. If a spoke is to be of a straight-gauge, DT Champion for example, the spool of wire is fed into a spoke manufacturing machine where it is cut to length, the end threaded and the spoke head manufactured. If butted spokes are desired, the wire is cut into prescribed lengths and blanks are manufactured. In this step the factory forges butting profiles needed. The blading process is a separate step, performed by a different forging process. The only part of the process that DT Swiss does not oversee is the manufacturing of raw materials into the finished spools of wire. Everything else is done in-house.
Contrary to popular belief, butted or bladed spokes are not "drawn" or stretched into their butted profiles by DT Swiss. Most people think the butted portion of the spoke is stretched into shape that is the finished product. This is not the case because it would leave the metal strained and weak. The butted spoke is actually is forged into its shape and while the process may seem similar, it isn't. The forging process allows the metal to be compressed into a denser package and this strengthens the metal by aligning the grain, giving rise to a part with improved strength characteristics.
In essence, the spoke can do more with less - if you get my drift. Think of a blacksmith manufacturing horseshoes. The metal for the shoes is not only hammered into shape, but is made denser through the process, thus removing voids and gaining durability through working the metal. Stretching the metal does the exact opposite.
In essence, the spoke can do more with less - if you get my drift. Think of a blacksmith manufacturing horseshoes. The metal for the shoes is not only hammered into shape, but is made denser through the process, thus removing voids and gaining durability through working the metal. Stretching the metal does the exact opposite.
DT Swiss uses a type of radial forging machine to butt its spokes that operates similar to this drawing. Also called rotary swaging machines, they operate by rotating a ring of rollers (7) that press down on plungers (2) as they roll over them (9). The plungers squeeze dies (3) that force the spoke (5) into a smaller diameter as it is fed through. Radial forging is a very precise and repeatable method of forming round shapes. (US Patent drawing)
Reduced aerodynamic drag is not a factor for off road cycling, so why do mountain bike wheels sometimes use bladed spokes?Given that our aero spokes go through an extra forging process, they do gain some strength over their round cousins. Also, bladed spokes provide additional stiffness under braking and acceleration loads.
DT Swiss uses a different forging process to profile its bladed spokes. Top secret, of course. (RC photo)
What kind of stainless steel is used to make DT Swiss spokes?The blend of alloys and metals we use is kept under lock and key and is a strict company secret. Our formula is proprietary to DT Swiss and we've worked for countless years developing it. What I can share, is that we buy our raw materials from vendors that we've had long-standing partnerships with. We value these supplier relationships because they are able to provide us consistent product and the high level of quality control we demand. When you shop around for the best deal, this control is lost and the end product suffers - all to achieve a lower price. We are ultra-hyper about the quality of our spokes and starting with great materials is the best way to put the best finished product out there.
Is there any sort of heat treat process involved in the making of a spoke?Not in the manufacturing of the spoke itself, but from the raw material stage to the bulk wire stage, yes. After that, all processes are done at ambient temperature. All of the forging and manufacturing processes are done without heat. This allows for better control, given the scope of product we are manufacturing.
DT Swiss states that the type of application, not superior strength, is the determining factor for using aluminum nipples rather than conventional brass items. They offer square, hexagonal and Torx type drive interfaces as well as a variety of anodized colors. (DT Swiss photo)
What is the difference in strength between aluminum and brass spoke nipples?I think it's better to attack this from a "pros vs. cons" debate between the two. The advantages to brass nipples are they are less expensive to manufacture, and due to the harder material (brass), brass nipples are less prone to rounding by the nipple wrench. Brass nipples are better for wheels that see more service and are used in corrosive or dirty environments. Brass nipples can also be a bit easier to build with because the nickel-plating acts as a "lubricant" allowing them to spin a bit more freely under tension. The main disadvantages to brass nipples are increased weight and limited color options.
Alloy nipples have their place too. They are lighter and reduce rotational weight at the rim which some users feel is critical. Colors and build personalization abound with alloy nipples. Numerous anodized color options are available to help customize any build. There are some things to be mindful of when using alloy though. Due to the softer metal, care must be exercised when building/using alloy nipples in order to not round the nipple at the wrench flats. This is where our Hexagonal or Torx nipples really shine. Both offer more purchase for the nipple wrench and allow for better performance. Corrosion can also plague alloy nipples being used in high-mileage, all-weather applications. Typically, this pertains to wheels that see little maintenance and many, many miles in wet environments.
As a side note to the nipple discussion, DT Swiss manufactures nipples for just about any application imaginable - different materials, colors, wrench interfaces or locking agents are all available from DT. I point this out, because choosing the right nipple for the build shouldn't be an afterthought. Proper nipple choice (I can hear the funny reader comments now....) is just as important as choosing the right rim, hub or spoke.
Alloy nipples have their place too. They are lighter and reduce rotational weight at the rim which some users feel is critical. Colors and build personalization abound with alloy nipples. Numerous anodized color options are available to help customize any build. There are some things to be mindful of when using alloy though. Due to the softer metal, care must be exercised when building/using alloy nipples in order to not round the nipple at the wrench flats. This is where our Hexagonal or Torx nipples really shine. Both offer more purchase for the nipple wrench and allow for better performance. Corrosion can also plague alloy nipples being used in high-mileage, all-weather applications. Typically, this pertains to wheels that see little maintenance and many, many miles in wet environments.
As a side note to the nipple discussion, DT Swiss manufactures nipples for just about any application imaginable - different materials, colors, wrench interfaces or locking agents are all available from DT. I point this out, because choosing the right nipple for the build shouldn't be an afterthought. Proper nipple choice (I can hear the funny reader comments now....) is just as important as choosing the right rim, hub or spoke.
A split view of a DT Swiss Pro Lock nipple shows its pre-applied thread-locking material, as well as the unthreaded section of the bore that acts as a stress reliever where the spoke enters the nipple. (DT Swiss photo)
How are the threads applied to the spokes?They are rolled under high pressure. Rolling the threads does not remove material as cutting does. Plus, it allows the spoke and nipple interface to have a tighter tolerance fit. This promotes a longer lifespan for both the nipple and the spoke by avoiding broken threads or stripped nipples. It is for this reason that we recommend against shops cutting spokes to length using a spoke machine. A lot goes into manufacturing a spoke into the finished product that you see at the shop level. And all of these processes are done with machinery that is specific to DT and our spoke production.
Spiral grooves in a pair of rotating bars advance blank spokes through this machine, where they are measured, cut to precise length and the threads are rolled onto the ends. (DT Swiss photo)
Is there any significant loss in strength between a J-bend or a straight-pull spoke in real life? J-bends spokes tend to suffer more breakage issues due to poor build quality and low spoke tension. Also, some hubs have spokes holes too large, which causes poor fit of the elbow. Most of the time you can chalk up premature J-bend spoke breakage to corners being cut in the wheel-building process. For example: it's always surprising to me to see a shop build wheels without the use of a spoke tensiometer. To me, that's like trying to build a house without a tape measure! I can't speak for other brands of spokes, but I can say that our J-bend and our straight-pull spokes are very close in quality and strength. Going forward, DT Swiss will be offering more versions of straight-pull spokes due to numerous requests as field replacements on other brands of wheels/build, or for new wheel builds on DT hubs.
The classic 'J' bend spoke head of the DT Swiss competition spoke. Reportedly, the J-bend will stand up to an equal amount of abuse as a straight-pull spoke will - as long as the hub flange design is correct. (DT Swiss photo)
Is a double-threaded straight-pull spoke stronger than one with a formed head on one end?Double-threaded spokes are more of design criteria brought on by hub/wheel design. An example of this is our Tricon family of wheels. The unique design of our hub mandated the need for double-threaded spokes. It is important to note, DT does not offer double-threaded spokes for sale as an aftermarket item. This is due to a bit more complex calculation of the lengths needed to properly build the wheel. Besides, there are little to no hubs being offered as aftermarket product utilizing double-threaded builds.
Tricon hubs use double-threaded, straight-pull spokes, partially because DT Swiss must weave the spokes into an undrilled tubeless rim during the build process. (RC photo)
What is the difference in thickness between the original coiled wire and the finished spoke?Essentially none. All spokes start out at their base gauge, 1.8, 2.0, 2.34mm, etc, and are forged into the butting profiles desired for the application. This is where the differences in gauges (butting) comes in.
Is butting a spoke done only to save weight, or are there other benefits?To reiterate, our butting is done by forging which actually increases strength of the spoke. So the end result is a product that is not only lighter but also stronger. Some wheelbuilders would also argue that a butted spoke is also a bit more "elastic." The butted spoke allows for a bit more flex allowing the wheel to deflect and return to shape, whereas a straight-gauge spoke is less yielding. Like the old saying goes, "like a Willow tree in the wind, it bends but never breaks...." Corny, I know.
DT Swiss uses a special 'anodizing' process to produce its black spokes. White and spokes featured in other colors are actually painted individually. (DT Swiss photo)
What is the typical tensile breaking strength of a DT Swiss spoke?I could answer this question with endless amounts of data, charts, QC studies and blabbity, blah blah blah.....but that would be boring and overkill for 98-percent of your audience. Here's the best way to address the topic: even our thinnest spokes will hold more tension than the strongest rim and most hub flanges. In other words, it's pretty dog-gone high!
The DT Swiss factory in Biel, Switzerland. Spokes in one millimeter increments are packed by the hundreds in cardboard boxes on the left, destined for bike shops and specialty wheelbuilders - and by the thousands in the metal boxes on the right, earmarked for OEM manufacturers around the world. (DT Swiss photo)
How many spokes will DT Swiss make in 2013?Too many to count! We are one of, if not the leading spoke supplier in the cycling industry for both the OEM and aftermarket segments. To meet this demand, we have spoke manufacturing facilities in Europe, Asia and I'm proud to say, the United States. We are an important supplier to some of the best bike brands and some the best wheelbuilders in the world - something we're really proud of. Our company was founded on spoke production and it's deeply rooted in our culture. It's been an important part of our business for quite some time, and it provides a strong foundation for all of the products we produce now and in the future.
More about DT Swiss
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Must Read This Week
mpitt - Crikey! Ireland is a small island as well!
DT Champion 2.0 of course!
I recently acquired a wheel with the original XT hub, the original Sun Rhyno rim, and DT spokes and brass nipples. Everything is in great condition except the hub, which was completely wasted(most likely from over-tightening from a hack mechanic), and the wheel is probably almost 25 years old! Anyways, I'm planning on re-using the nipples on my next personal DH wheel build, that's how much confidence I have in the DT brass nipples and I look forward to testing then with confidence. I would rarely re-use aluminum nipples because I don't have the long term confidence in them. I might even use the original Rhyno rim on another bike, and luckily the wheel is a 36 hole so I'll have four nipples to spare in case any were damaged by the previously mentioned hack mechanic who over-tightened the hub.
To Lock-tite or not to lock-tite?
I was the wheel builder at Planet-X for just over 2 years and built over 3000 wheels in that time, plus plenty since then for myself and friends.
I've always been pro lock-tite, but I know other wheel builders who's skills I also respect, say no to lock-tite.
It always turns into a massive argument when it comes up in the pub
never used loctite myself
should not need to rely on a thread locker to prevent spokes from unwinding on the nipples, if the wheel is built correctly?
and never using aluminium alloy nipples for customers in the UK, we have rain and more rain plus mud and road salt = premature seizure!
always found much better results using Park or DT spoke tension meter to check spoke tension whilst building, kinda scary how few "pro" shops even use those tools, claiming their experienced wheel builder "know better..."
when DT Swiss designed and built their first spoke tension meter; the story goes they gave the tool to some very experienced pro wheel builder in Europe (guys in their 40s and 50s who had built 1000s of wheels for the Pro road tours and discerning customers)
the majority found their "experienced hands" were actually up to 20% out in terms of spoke tension compared to using the meter! This makes a massive difference to the durability of the wheel.
its also interesting to take the spoke tension meter and apply it to brand new wheelsets coming on production bikes, and even "factory wheels" selling even at the high end and see how absolutely shockingly bad, most wheels are built
"Wheel Shaped Objects" my old Cytech training manager would call these structures...
if you try, you can actually build a very good wheel using the spoke tension meter and very little visual inspection of the wheel jig / rim, like flying a plane blind using "instruments"
Building wheels isn't some black art, you don't need 20 years experience and some kind of "gift" to make a wheel last. Just follow a pattern and a bit of common sense will get great results. I've not had to true my wheels for over a year now and that with heavy street use with failed spins and tailwhips and that was without a gauge.
It doesn't surprise me that a company that makes a tool would suggest that people who didn't use their tool didn't do as good a job.
The important part is the stressing of the wheel, most people just bend the wheel over a desk/lap or bend it with their arms and elbows or maybe press it against the floor. For a super strong wheel that's just not enough in my books, I find putting the wheel on the floor and stamping on it gives best results, though not advisable for lighter XC or road rims.
I'd never consider using Brass nipples either, there's just no point, lubed alloy nipples will still be useable years down the line, they can allow tighter spoke tension (I'll explain if needed) and they are lighter, win win.
The one thing I found informative about this interview was to learn that butted spokes are in fact stronger than their straight-gauge counterparts, and not just for the reasons I usually hear (elasticity, magic, blah blah blah)! Thanks for that!
Off course I could switch to BMX or street bike but I hate Hip Hop...
Cheers...
What flex more of the two?
What happened to DTs Titanium alloy spokes?
There was a guy from my home town in Poland who worked in old sailplane factory who made a bunch of carbon spokes for his road bike, it was like 20 years ago. Very impressive... and scary! They were literaly like strings. They had molded steel inserts at both ends, at head and at the thread, both with a hole through which he dragged fiber like a string through a nitting needle. Then he put rusin on it using a brush and used two sheets of glass as a "form". It had a flat reinforced piece around thread near the nipple to hold it so the "spoke" wouldn't rotate while truing.
They were probably strong for stretching, but probably didn't not weigh much less than current steel ones. They must have broken like glass if something came into them... ridiculous yet fascinating
I disagree, Brass is a harder material and imperfections in the thread of the nipple and spoke rub against each other and cause friction making them harder to turn. Alloy being softer has a little "give" and the imperfections get smoothed out by the harder steel threads of the spoke, giving less friction and a smoother turn.
I always use alloy nipples and I ride street, the ones on my bike now are at least 2 years old and on their second build. Never snapped or rounded one and I run REALLY tight spokes.
Sounds like a bunch of engineers talking. They think they know everything. From ACTUAL wheel building experience Brass nipples have much higher friction under high tension than Alloy, no amount of "but alloy sticks to drill bits" will make me change my mind. I've snapped Brass nipples when building wheels and I've yet to snap an alloy one even at higher spoke tension (yes I have checked with gauges).