As a tensiometer maker, there is no such thing as “too precise.” In that quest, we’re constantly improving various elements of our design and process.
The past year has brought better calibration fixtures, instruments, and insight. So here is a new chart that applies to all dial tensiometers and digital models including Mitutoyo and IPIC.
The first Wheel Fanatyk design (known as “Original”) does not share this new chart; neither do similar models such as those by FSA and Avocet.
The tension visualizer utility by SpokeService.ca has been updated to show these new calibrations. Most importantly, we have better precision throughout the range of spokes and tensions. We’ve also added 1.65mm spokes, made popular by Sapim’s D-light.
Download a pdf copy of the chart here. Enjoy precision!
As gravel beckons, where are we with disk road wheels?
Disk brakes have come late to road bikes and, until recently, have met a cool reception. Two questions arise:
1/ Will the feel and response match the best rim brakes?
2/ How well will road wheels support disk brake loads so fundamentally different than rim braking?
As we northern climes head into damp weather and cyclocross, issues of corrosion deserve attention. Corrosion cannot be ignored but, for cycling, most of its challenges can be addressed.
Beware viewing extreme cases of corrosion on the Web. An incident only matters in terms of frequency. Being one of 1,000 witnesses to a wild case may not have statistical validity. Shape your practice around incidents that are representative.
Corrosion ~ oxidation ~ redox ~ rust
Beware, I’ll be interchanging these terms, most unscientific! To begin, corrosion is universal. Everything oxidizes under some conditions, life depends on this chemistry. It simply must be controlled and limited to an acceptable rate so we get good use from our wheels.
In general, corrosion is not a main driver of component failure, but is always present at the scene and often a player. Where a failure has occurred, note all the detail you can but be cautious assigning relative importance to each factor. A badly rusted hub bearing may show extreme wear but as it takes time and/or negligence to blow bearings, the coincidence does not define causality.
Corrosion is related to both material and environment. Warm, humid, coastal areas with onshore breeze and mist are hugely more corrosive than elsewhere. Components designed for average conditions need more care (rinsing) in FL or HI. In those areas, brass nipples can turn black with corrosion and crumble to dust. If you respond by cleaning and lubricating you might not feel aluminum is such a bad nipple material. Its corrosion is similar to brass and, maintained, can be reliable.
Corroded hub shells are ugly. Chalky stains and pits can be impossible to remove. Anodizing provides a first line of defense. For hubs that are uncoated, a high polish is more corrosion resistant. Campagnolo’s early hubs were polished and builders cleaned and shined them before a build so subsequent maintenance was easier. Surface treatments like original WD40 go beneath water, clinging to metal surfaces. A light spray or wipe can minimize corrosion.
Today’s better spokes are made of stainless steels, corrosion resistant enough to not require protective coatings. These steels can corrode so don’t be surprised to see a light haze of rust. Wipe it off with an oiled rag. The black color applied to many stainless spokes is decorative only and not as corrosion resistant as the underlying metal. A light haze of rust on a black oxide coating is easily wiped off with an oiled rag and will not rust again until the oil is removed.
Remember that multiple stainless alloys are used for spokes, each with different metallurgy and corrosion resistance. Likewise, there is no single black or color coating. Integrity of a coated spoke is difficult to predict without access to manufacturing details.
For non-stainless spokes, galvanizing is a common corrosion prevention. It begins as a shiny, attractive layer, quickly becoming dull, industrial gray. This is normal. On show motorcycles and antique bicycles we see chrome or nickel plating. Neither has much corrosion resistance without regular wiping and application of a protective polish. I’ve seen bad rust on non stainless spokes but rarely breakage for which the rust could be blamed. Of course, it happens but is rare on in-use wheels.
Wiping spokes with a rag lightly soaked in an oil of your choice is good practice. Pressure washing removes dirt but dirt doesn’t cause corrosion. Washing removes the protective coatings all components need. We’re in a modern world of materials and coatings but superficial oils and waxes still play a key role for weather resistance.
The debate over brass vs aluminum nipples is eternal. The issue should be decided on mechanical attributes, not corrosion resistance (IMO). Both are quite similar and a well anodized aluminum nipple can equal brass with a nickel plated finish. Brass is more ductile and self lubricating. High grade (2024 and 7075) aluminum is stronger, can be brightly colored, and a bit lighter.
Check this chart for comparable corrosion. The first two columns are aluminum and brass. For exposure to sea water, the two metals are similar. For distilled water, aluminum is excellent and brass is bad. For vinegar, aluminum is better. For boiling whiskey, brass is better. Two metals with different outcomes depending on environment. I’m for the whiskey.
In navigating the “controversy” remember that much unwelcome behavior by any single batch of nipples may depend on specific conditions. What, if any, lubricant is used? What process shaped the nipple (forged, cast, machined)? What plating and specification (depth, penetration) was used? Silver nipples are not necessarily anodized. Are yours? Notice also that many millions of aluminum nipples have been used on production wheels over the past 20 years; most outlasting their spokes, hubs, and rims.
Brass contains lead for formability. Recent law restricts the amount but the historic presence of lead in brass taints its otherwise classical charm. Regardless of nipple material, regular lubrication is key. If you soak nipples in heavyweight oil prior to building, the coating can last years. If your wheels see pressure washing, relubrication is required.
To lube a built wheel, touch a drop of light oil to the spoke as it enters the nipple. Watch it wick down the bore. A second drop belongs at the nipple-rim contact, applied from the same side. Spinning the wheel creates centrifugal force to drive lube into the assembly. Many of today’s chain lubes are ideal for this as they are thin for application and penetration but as their carriers evaporate the remaining formula becomes dense and long lasting.
Cracking of aluminum rims under tension at nipple holes can be accelerated by corrosion. After anodizing, rims are purged of liquids used in the electrochemical process. Inadequate flushing can leave seeds of corrosion deposited inside the rim. Anodizing can be too deep and hard, leading to surface cracking where the rim may be deforming from spoke tension.
Tire sealants can also be corrosive agents and leak into rim interiors, especially those with ammonia.
Carbon rims are neutral for corrosion but can act as anodes when in contact with metals, stimulating corrosion. It is relatively easy to isolate and protect such galvanic combinations with anodizing, washers, and lubricants. For better or worse, the vast majority of carbon wheels are built with aluminum nipples, showing the combination is not automatically bad news. Enve’s recent switch from aluminum to brass for internal nipples does not indict all use of aluminum. Many of the problems they observed are owed to ammonia from tire sealants and poor anodizing on nipples. Substantial numbers of carbon wheels show no aluminum nipple corrosion. There is often more to the story than simply nipple material.
Storage batteries in use or awaiting disposal can create electrical fields that produce very corrosive conditions. When you see an “impossible” corrosion example, wonder about the context. With growth in e-bikes, e-cars, and home energy storage, we can expect more such cases.Electrical fields…?
In following corrosion, make careful observations and notes, utilize magnification and photo images, and use components with highest material and coating properties.
This upcoming La Niña winter should be fun, not corrosive!
Nipples aim from their rim holes in order to align with spoke angle. The goal is to have no bend in the spoke as it enters the nipple because threading there is a weak spot. Spokes can fracture in thread roots after many loading cycles. Nipple and rim shape determine the amount of spoke angle that can be accommodated. The angle is a product of hub and rim size, spoke number, and crossing pattern.
Today, rims are frequently smaller (650 instead of 700, 20” for folding, cargo, and e-bikes, etc.). Hubs can be larger (generator, internal gear, e-motors, etc.). These combinations produce spoke angles that are more concerning.
A perfect spoke angle is 90deg with no bend in the spoke. Side angles generated by hub width and dishing are rarely below 80 and most nipple-rim combo’s handle them. The angles we need to address are in the rim plane and a function of rim and hub size.
Grin offers a great spoke calculator, among many valuable resources. It will determine the spoke-rim angle and, incidentally, works with paired spoking (another topic). Nipples can easily aim for entries of 80-90 degrees. Less than 75 may be accommodated. Below 70 is beyond most components and requires special attention. Solutions:
1/ Kink the spoke with a plier or wrench so it enters the rim at the nipple’s angle, a slow but effective process.
2/ Drill holes larger so nipples are freer to pivot, not an option or advisable on many rims.
3/ Reduce the lacing cross number to make an angle closer to 90. Despite sub-optimal torque geometry, many builders are doing it. As Grin says, “In spite of the popular wisdom not to use radial lacing on drive wheels, empirical experience has been that this isn’t really an issue with the large hubs in small rims.” The burgeoning e-bike scene cannot be slowed down even though appropriate rims are not available.
4/ Rims could address this issue, for example, with a bulge at each nipple. Motorcycles figured this out 100 years ago. Drill the rim to accommodate the required angle. Here is a solution with optimal spoke angle and torque transmission. Cycling will certainly figure this out soon.
Anticipate spoke angles and plan accordingly. An engineered solution to the situation requires initiative from rim makers. Let’s hope it is sooner than later so I can stop envying motorcycle wheels!
You’re building along when a nipple runs out of spoke thread. You feel an increase in friction as unthreaded spoke shaft encounters nipple threads. This can occur with a slightly too long spoke (or too small rim). What to do? Consider turning the nipple further into this stiff zone. Why?
1/ Nipples are softer metal (brass and aluminum) than spokes (steel) and their threads yield with minimal resistance. Also, spoke thread is rolled so peaks are above the spoke surface and valleys, below. When the nipple encounters the spoke shaft, only 1/2 of its thread must yield; far less interference than between two machined threads.
2/ Spoke threading, as with most thread forms, carries the entire tension load on 3 or 4 threads. The rest are available but not load bearing. Driving a nipple down a spoke a few turns past threading has inconsequential effect on load carrying capacity.
3/ Testing shows that nipples support spoke threads. When a few spoke threads are not engaged and when the spoke endures riding induced load cycles, fracture can occur in those empty threads. Full engagement increases spoke fatigue life for thread fracture. It would be an enlightened building strategy that forced all nipples to be turned further so no spoke threads were empty.
4/ A nipple driven further down a spoke develops friction that helps prevent vibration induced loosening, a good outcome for any hard-used wheel.
Beware of excess spoke protruding from the nipple inside the rim, it may interfere with the tire. Otherwise, please remember the possible benefits of tightening nipples past the spoke threads. Not all bad, in fact, there are some interesting benefits.
Now is a good time to introduce a new product, a better spoke ruler than any before. This ruler is by Pi Spokes, a very interesting project of which you will hear more in the future.
1/ At long last, a ruler marked in 0.5mm increments. These finer increments are easy to read (or ignore). Let’s face it, spokes are not all made exactly to whole millimeter lengths. Builders deserve to round up or down with complete accuracy. Spoke machines like our Morizumi can also cut precisely to 0.5mm so a finely graduated ruler is perfect.
2/ The spoke lies in a groove below the scale so the issue of visual parallax is minimized. Lengths can be more quickly established, even in poor light.
3/ One side is for J-bend elbows, the other for straight pull. The ruler is made of highest grade aluminum, scale is permanently laser etched over bright purple anodizing. Price is $20.
Wheel building is booming, though it’s rare to see evidence in the cycling press. I’d call it a work in progress, rather like craft brewing back in the day. Pioneers were scrappy and uncertain. When they first appeared, the big brewers knew it would be sporadic and limited (college towns, resorts). They actually got murdered over several decades and now craft brewing carries a large percentage of that market. This seems to be happening with wheel building.
Today most small builders are in likely cities (Portland, SF, Seattle, Boulder, LA…) but their global rise (UK, AU, NZ, EU…) shows it’s not a local trend. Your area may be barren but many successful builders are elsewhere. Check these, among hundreds more:
Not personal recommendations (but all excellent). The more you look, the more you’ll find.
If you are contemplating getting underway I recommend exploring two questions.
Where Am I?
You may plan a strong web presence but your immediate scene is your most important asset. Local riding is a key element in your opportunity.
Put aside personal preferences and experience because, as a wheel builder, you should welcome, understand, and whisper to all forms of wheels. Can’t do too much research and preparation to cultivate your local community.
Who Am I?
There are many types of builders. Wheel construction seems pretty straightforward but those who succeed do not share one approach. One science I hope, but not one style. Who are you? Understanding your style helps direct your effort and avoid confusion.
Handy with tools, good with gear, likes self sufficiency, finds building fairly easy, builds own and wheels for friends and family. Not so keen to make a simple task complicated or dramatic.
If you’re gregarious, wheel building can bring quite a range of human variety your way. Creating a business around the needs and exploits of riders is attractive to customers. You’ll want a welcoming workshop with plenty of ambiance and regular outreach.
Many an engineer type is drawn to building and customers, in turn, to them. Emphasizing tech with gauges and instruments, sharing spreadsheets and charts, teaching the “how” behind wheels can be a central theme if that is your drift. But it is not necessary to reek of tech. Performance minded customers need to trust but rarely require knowing all about the science.
Wheels are beautiful and there is room for plenty of self expression for a builder. The bar is very high for visual compatibility with the bike, high finish of components, and unity of design. Aesthetics are an ever changing scene, rules flex, styles evolve, and builders help drive change. We’ve all noticed what fixies combine on machines so basic they simply showcase wheels.
We are combinations of such types but discovering that inner builder is key to separating your offering from vague and mainstream options. Riders seek custom building for more than alleged benefits of value or performance. They want to deal with a real person, not just an “add to cart” button. There is no “better” style but the clearer yours, the greater authenticity you broadcast.
Authenticity attaches to wheels, gives them karmic power riders remember for years. Authenticity of our prized possessions adds meaning to our lives. That’s your ultimate product as a custom wheel builder.
Go for it and please share your experiences with others (and me :-)!
For current or aspiring bicycle mechanics, this is an exciting time. E-bikes, advanced materials, fun new categories, more diversity, mobile service, better tools, wow…the list keeps growing.
Check out the, just announced, technical workshops held by PBMA (our fledgling but dynamic mechanic association).
Coming later this year and next to Colorado, Portland, and Virginia. Most of the leading industry players are participating.
There is room for just 120 mechanics at each so early registration is the only way to guarantee going. There are scholarships available, so be bold and apply!
Let’s talk rotating weight. Rotating weight is a big issue for wheel builders. Why? We make choices that determine wheel weight, its total and location. Builders must understand this topic.
Rotating weight directly affects inertia, so the topic is really inertia. Inertia is the resistance of a mass to acceleration. Moment of inertia (MOI) characterizes this resistance and depends on rotating and non-rotating mass. Builders should be measuring wheel MOI.
I’ll show you how to measure moment of inertia (MOI), plus I’ll share a spreadsheet to shortcut the math supporting MOI measurement and its effect on riding. Plug in numbers and get usable wattage estimates. Read more →
I once called tensioned wire wheels “the most ingenious contrivance in all of human engineering.”
Extraordinary claims must be based on extraordinary evidence (Carl Sagan) and tensioned wheels have it in spades. Think, more than two billion nearly identical wheels see daily use on our planet. There is no widely used structure with such astounding strength to weight, and they conquered gravel on the moon!