This is especially for those who cut and thread spokes. Be it with a magnificent Morizumi or a venerable Phil Wood machine, thread rolling is the game. While industrially commonplace, it’s not well understood by those who do it daily.

How Things Work
Quite a few of you like to figure how things work. Here is a glimpse into the nature of thread rolling. The die set (a pair of flat plates with grooves) that makes spoke threads (by rolling a spoke between ribbed surfaces) has grooves spaced at the thread pitch.

Super hard, super precise – that’s a die to live for.

So there should be a die size for each spoke gauge, right? The gauges:

A total departure from World fastener threading policy!

Here is the conundrum: the thread pitch for bicycle spokes is the SAME regardless of spoke gauge. Huh? One of our brilliant predecessors ordained they shall all be 56 threads per inch (metrically speaking, 0.45mm pitch).

Isn’t that Illegal?
Name another fastener where the pitch does not become finer as the diameter goes down. That’s to minimize breakage and it’s universal practice. What good’s a World Order if not to standardize things that work better?

Except bicycles. Basically, we (cycling) make our own rules. We discovered this short cut works. Theory out the window. Let’s make bicycles simpler to understand and to make. From a wheel builder’s perspective, thread pitch determines the feel of wheel truing. 1/4 turn of a nipple makes a similar dimensional change to length regardless of spoke gauge. That is the idea behind a universal thread pitch.

One More Logical Step
Since we have adopted the same pitch for all these spoke sizes can we use the same dies to make the threads? Just run them farther apart for thicker wires? All 56 threads per inch? This is a challenge to the laws of physics.

Even wizards can’t break the laws of physics!

A die has small grooves that make peaks and valleys of the thread form. These grooves are set at an angle specific to the diameter of the spoke. As the spoke rotates, grooves are created simultaneously on each side, that  eventually meet up to create a continuous thread.

For a smaller diameter spoke, the angle is greater (from perpendicular) because a small circumference means a groove gets around more quickly (and must not run into itself). A larger diameter spoke (12g is 30% greater circumference than 14g) means a greater distance for each rotation. The groove angle must be smaller so the thread is continuous.

Wiggle Room
The actual change in angle from 15G to 12G sounds like it would be significant (according to the circumference difference), but it’s tiny—about 1º.

In practice, there is plenty of tolerance (wiggle room) and dies optimized for smaller gauges (15/14G) can roll perfect (to-the-eye) threads on larger gauges (12/13G). For this practical benefit we encourage all bicycle gauges be threaded with the same dies. It works!

Now go forth and thread like guru’s!

OK, back in time for a little story.

Casey Jones, you better watch your speed.

In the early Industrial Age, metals were at a primitive state by today’s measure. The Iron Age succeeded the Bronze Age, iron being stronger and lighter, around 1200 BC. This material has been with us for nearly two millennia. By the 18th century, humanity was enjoying three forms:
(1) Wrought iron – a strong, malleable, low carbon alloy,  not brittle, but too soft for serious structures or cutlery.

(2) Steel – made from wrought iron by increasing the carbon content. The only means to make it were very slow and expensive so it was reserved for cutlery, armor, and weapons.

(3) Cast iron – high carbon content, quite hard but brittle and weak (except for compression loads). Possible to make into complex shapes but structurally (buildings, bridges, ships, bikes) fairly useless.

This scene blew apart in the mid-1880’s with a new way to make steel cheaply. Bessemer discovered how to reduce the embrittling high carbon of cast iron. Result: plentiful strong material and a very rich Andrew Carnegie. Humans, being ambitious energetic mammals, go crazy with opportunity. Noticed? Materials have often made men mad. Cast steel and steel tubing had some of the widest fan bases.

Read more →

A Nerdy but needed discussion
Economics is the engine that drives the human experiment. Many events embellished by history as “clash of religions” or “perceived insults” or “cultural collisions” are, on closer analysis, driven by economic forces. Salt, gold, trading routes, lumber, silk, these were often the real goals.

Bottom line: too little attention is paid to the economics of matters, in particular bicycle wheel building. For each perceived objection about shop wheelbuilding there are good economic solutions.

Objection – Lack of resources
“I can’t afford to stock wheel components. There’s no choice but readymade wheels.”

Solution – Decide how many wheels you want to sell. Without projections, you won’t get anywhere. Ask other stores and experts (I answer inquiries). Now back-calculate an affordable inventory size. That’s what you must work with. Today’s JIS (just in time) distributors make quick ordering a reality. Use it. For years at Wheelsmith we stocked only Mavic rims. There were fewer choices those days and Mavic mainly sold rims. But our purpose was to reduce inventory. Look at a small restaurant’s menu. Their decisions are often more about what not to offer. You can also hugely cut down spoke inventory with a cutting/threading machine.

Objection – Takes too long
“I can’t find a fast wheelbuilder.”

Fast builders dislike interruptions. Here, one too many triple latte’s?

Solution – Fast builders are out there. Advertise, make it worth their while. Uncertain? Then pay by the wheel. Make sure they take home 50% of your customer charge. The difference between a slow and fast builder is huge. Slow builders may love the work but are often impractical perfectionists stalling on details, talkers, whiners, and wanting to work less, not more. Fast builders are often modest, quiet, dislike interruption, and welcome more work. Whether it’s wheelbuilding or cleaning fish, trust that some people are blazingly fast and enjoy the work. Dismiss rumors from bike advertising, your Big Brand rep, or slow builders that they don’t exist.

Objection – Technology
“Big Brands have awesome technology I can’t match.”

Solution – Big Brands can buy persuasive ads, trademarked acronyms, and sponsored pro’s. In spite of all that, many fail to impress anyone. It is fun to analyze claims and performance. On all counts that affect your customer, readymade wheels are often not the best. For weight, value, beauty, function, and match to the user; made-to-order wheels can be a step ahead.

In 1960, 2/3 of the man-hours to make a Raleigh were spent building the wheels.

Objection – Expensive tooling
“I can’t afford all the gizmo’s the Big Brands show off in their video’s.”

Solution – For one, Big Brands don’t need a lot of that equipment (dynamic computerized load testers, wind tunnels, etc.). For two, shops can afford more than they think. Bike shops are a blend of commodity merchant and manufacturing. Few businesses are more different. Merchants put money in inventory and measure it by turn and margin. Manufacturers buy expensive equipment and own it for many years. A lot of calculation goes into whether a $50,000 tool is affordable, math that merchants don’t need. For example, if I show you a tool that saves $2K in inventory or speeds your building 20%, can you tell me what it’s worth to your business? You need to.

Obstacle – Automation is the future
“Everything is automated. I should let robots build all my wheels.”

Robbie says, “oops, sorry.”

Solution – Automation is the future for mass produced commodities (hubs and rims, for example) but not for a zillion needs in our economy. Wheels for IBD’s (independent shops) can be mass produced but only made-to-order can meet varying customer need and timing. Besides, you might be stunned to learn how many millions of wheels are made worldwide without robots. Short production runs, the cost of  setup with automation, the need for careful handling and highest quality, all keeps hand building a major force. Look how craft breweries, wineries, and distilleries are claiming such a large part of the beverage market, IBD’s and IWB’s (independent wheel builders) continue to hold significant share.

Economic trends are pendulums with slow, broad swings and over correction. We’re now in a phase where IBD’s and IWB’s are reclaiming wheel market share. In 2013, Mavic’s sales were up only 1%, Easton down perhaps as much as 30%. Other Big Brands did not fare well either. No reason to rejoice, we all want a robust wheel scene with winners big and small.

However, the trends are clear and if you want your share, check the economics!