Sunday, May 19, 2013

The Wheel's Six Tricks

Bicycle have lots of karma and charm. A collection of gem-like devices, individually clever and, when connected, produce a mechanism that's brilliant. Like a skilled acrobat, its accomplishments seem like tricks.
Don't try this at home.
Among these devices, I'm partial in the extreme to wheels. Puzzling through the years over this irresistible attraction, I've discovered some clues. The wheel is not singular. It's a multi-function event whose complexity defies simple analysis. Like "flames dancing" (Duchamp) it is difficult to take in all these facets at once.

This is the hypnosis of a crafted diamond. Brilliant light shapes project in multiple directions. Move and you see something new. No two-eyed human can take it in at once. By the way, diamonds are one of the four forms of pure carbon* found in nature, and carbon is the sixth element.

Where are we going? The wheel does at least six independent tasks at once (not including its attraction of fools like me and Duchamp).

(1) A wheel: rotating about its center, enabling terrestrial mobility like nothing humans have yet devised. Due to a highly tensioned design, the bicycle wheel is unique and represents perhaps the apogee of wheel functionality. That story goes back thousands of years.
King Tut's hot rod.
(2) A tire interface: half the pneumatic tire system. Much of wheel design concerns the dimensional and force requirements of this challenge. When the pneumatic tire appeared, wheels got a supercharge.
BTW, what is a "26" or a "263"?
(3) Brake system component: for bikes with rim brakes (the vast majority), the rim is actually the disk of a disk brake system. Torque, abrasion, pressure, area, straightness, and heat involved in braking amount to a tremendous demand on the wheel's structure and material options. Hub brake forces are also key drivers of design.

(4) Transmission element: at least half your gears live on the rear wheel. The internal or external gears of the hub define much of this zone of the wheel. Consequent torsional forces must be addressed with many specific design features.

(5) Suspension: the spoked structure is resilient and flexible. Without some give, neighboring components (forks, in particular) would need to be much stronger. Seat posts and handlebars would break, not to mention extra vibration to the rider. The amount that a wheel flexes is a necessary element affecting the design of all other parts.

(6) Steering system: the front wheel is the gyroscopic part of a single track vehicles's stability. This feature (spinning mass creating strong directional forces) explains how bikes can be ridden by 4 and 80 year olds alike, learned by any person who can walk.
On board stability.
These diverse requirements of a bicycle wheel are the design demands that govern cost, weight, dimension, material choice, and force management. They define the wheel. It evolved to do these things. I want you to see them all when you behold or work on a wheel.

Let's explore these facets. I'll devote a blog post to each. So, with minimal interruptions, look for six episodes that illuminate this gem-like complexity.

BTW, "20 Tips" may interfere from time to time, but my aim is to cover these six dazzling tricks as swiftly and interestingly as possible.

* #1 - amorphous (pencil lead, charcoal), #2 - 2D (carbon fiber), #3 - 3D (diamond), #4 - Nanostuff (Bucky balls, etc.).

Tuesday, May 14, 2013

Celebrate

In the northern half of our planet, Spring is arriving. A time for renewal and time to celebrate our hobbies and the improving weather. Cyclists do this annually. Put on some miles with friends, visit your favorite climbs and descents, wear a new (or re-discovered) jersey, wrap your bars with a lively color.

But how do we share this joy with non-cyclists, family, neighbors, co-workers, customers? Sailors can put a boat model on the end table. Golfers have a variety of desk ornaments. Climbers can hang crossed ice axes on the wall. Baseball fans might show off an autographed ball under glass. What do we do?

Few riders have a display bike in their homes or offices. I've never seen a Nuovo Record rear derailleur under glass (nice idea, come to think of it). What bicycle part makes a handsome reminder of our passion and pleases our associates and guests? A wheel, of course!
Challenge one, how are we going to mount this wheel? Maybe just an upside down fork stuck into a stool with a hole?

This brings up an important subject, the tradition of displaying bicycle wheels is much greater than any other component, including bicycles themselves. Answer me this: what was the most ever paid for a bicycle or bicycle part? Time to place your bets, my friends.

Do not act surprised when I tell you about a bicycle wheel that crushes all comers. I'm speaking of Marcel Duchamp's Bicycle Wheel.
VIP Wheel.
Mesmerized by a spinning wheel in 1913, Duchamp mounted one so he could have uninterrupted access to its hypnotizing beauty. The original was lost, Duchamp became a father of the modern art movement, and he decided to recreate the display in 1951. In 2002 at Sotheby's in NYC, one of those replicas sold for $1,760,500.

I've been to IKEA, so I can estimate the stool price, about $49.95. And a nice painted steel fork can run $25.00. Therefore the wheel fetched $1,760,425.05. Find me a bicycle with a similar price tag. Go ahead, please, try.

Now back to celebration, why did Duchamp become so engrossed with a wheel? He mounted it in his studio without intention to make art of it. He liked it as a distraction, "I enjoyed looking at it, just as I enjoy looking at the flames dancing in a fireplace." He came "to feel that the wheel turning was very soothing." It's been 100 years since the concept, perhaps the world's first kinetic art. Yet the magnetic appeal of a spinning wheel is as strong as ever.

Hardly a person who approaches a mounted wheel can resist giving it a spin. If you work in a shop, you know what I'm saying. Interacting with a work of art is not a typical opportunity. You are giving a gift by making this possibility real.

How to start? A truing stand or upturned fork might do. Curtis Odom followed his artistic urge and created a timeless wheel display stand of which eight have been made. They were first seen at the Sacramento North American Handmade Bike Show in 2012. Here's the most beautiful wheel in the Show. Why? Because it's in the most beautiful stand!
A stand out visual.
Evoking Victorian cast iron decorative touch.
Stunning from any angle.
The point is more about celebrating the beauty of wheels. Any wheel. Choose one that's meaningful to you. The front wheel you rode across the USA. A wheel from your father's bike. Change it from time to time. Amuse your family and customers. Wheels have stories to tell, that's for sure. Put one in a stand and help folks appreciate the message.

There are cheaper stands, to be sure. This ultra-simple, brushed stainless display puts all attention on the wheel. We have nine of these. Maybe one belongs in your study, meeting or reception room, or on a counter.
Seven pounds of display elegance.
So consider celebrating your love of cycling with a display of its most visual element: a wheel. Choose one with a story to tell. Put it in a dignified or conspicuous place. Watch the smiles as folks gently turn it, gaze, and take a break from their hectic day. Embrace a great tradition of modern art and kinetic motion.

Tuesday, May 7, 2013

More About Spoke Lengths

OMG, some of the stories I could tell about spoke lengths. You think there are rules about spoke use? Length precision? Optimal cross patterns? Gauge choice? Replace or re-use do's and don'ts? Fugetaboutit.

None of these matters as much as having a working wheel. And scarcity will drive some interesting solutions. When I started out building, spoke supplies were terrible. The Schwinn empire was crumbling and their stocks of Berg-Union (Germany) spokes were full of gaps. You could get nice straight and butted spokes, but galvanized. The few chrome plated ones quickly rusted and the chrome process embrittled the metal. Try building from inventory measured in inches, every 1/8" from 11 to 12-1/8.

Robergel (France) was available from some specialists but only in butted 15 gauge. Pretty thin for MTB or tandems. In the Bay Area, we were lucky to have the dynamic of Spence Wolf and Phil Wood. Phil made great hubs with unexpected dimensions but any drilling you could name. Spence imported Robergel in as many lengths as he could stock. Wheelsmith got its start by buying obscure spoke lengths from Spence. How proud we were that you could get the length for high flange Campagnolo track hubs laced radial to a standard tubular rim. Hey, it was a big deal.
A Toblerone box. Almost as tasty.
Initially, we were lucky to have a few lengths in each range. Later, stocking even numbers was ambitious. So it was time for a spoke length calculator. The math is simple and ancient but convenience was needed. Jon and I grabbed a hand held calculator, first a Sharp. Back then (late '80's) such devices were like magic. And expensive. With programming help from Eric Topp (Stanford student racer, later engineer and designer), we unveiled the World's first Spoke Calculating System.
High tech, circa '90's.
Why such a creation? Not to blaze a trail of innovation in wheel design. No. It was born of the necessity created by scarce spoke availability. You always had to use a compromise length. With short, racing nipples, errors couldn't be more than 1mm or you had an embarrassing bunch of threads on view outside the nipple.

A spoke calculating system told you the exact length needed so you could use the wrong length with confidence. If it's going to be short, make sure not too short. If there are none for X3, then quick calculate X2 or X4. Maybe you have those. We built wheels with miss matched spoke gauges and crossings as often because we didn't have the right length as because we were doing some intelligent design.

Ha, those were good times. How about double crossing? I mean an over-under tuck, twice between hub and rim. Absorbed 1mm. I remember a wheel set with skinny, attractive Stella spokes (Italy) where double cross made using 302's possible. How else would we find out if X2 worked? Eventually spoke calculation became a given.
Uses 2mm extra. Honest.
With all the asymmetric thinking of a fast-emerging bike scene, Phil Wood came to the rescue with his spoke cutter and threader. Now bike, hub, and rim makers could let it rip. Calculate the spoke, cut it to length, and any combination could be built. Wow, like the light bulb! The scene really started to boogie.

How else could innovators like Tom Ritchey, the WTB scoundrels, Bontrager, Specialized, Gary Fisher, Santana tandems, and those HPV's of land speed record fame do their memorable work? By the early '80's we could support MTB's, funny bikes, and the 24" wheels of the 1984 Olympic Team. Sky was the limit and Scott Gordon and Andrzej Bek start making bladed spokes. Aero rims from Araya (JP) and Saavedra (Argentina) were welded and re-drilled to ultra low numbers.
286mm blades, 500 each, like currency.
Just remember, there is no "right" spoke length or pattern or gauge. It's the one you can make work. Necessity is the momma of invention. Could all of triathlon, MTB, aero, tandem, and suspension come from a scene that wasn't accustomed to rule breaking, that didn't learn during times of scarcity? When it comes to wheelbuilding, don't get too holy about rules and correctness. You are enjoying a scene built on poverty driven problem solving.

When things don't exactly match up, sit back, reflect. Maybe there's lemonade to make. No telling where it might lead!

Saturday, May 4, 2013

Tension Made Easy

I'm so glad we've sold over 100 tensiometers in the year since it was introduced. Only two had mechanical issues and most users are very pleased. It's also satisfying to know quite a few bought in addition to their DT tools.

DT is a particularly accurate and nice unit. Why buy a Wheel Fanatyk as well? A bunch of reasons. It's a more clever way to grasp a spoke, where the tool doesn't notice the spoke's thickness. The gauge is also mounted in the center of a triangular plate that offers protection. Other gauges are not to be dropped!
DT - don't drop!
Gauge protected.

But the most compelling reason is accuracy. DT is excellent at high tensions, even up to 150kgf; but at the expense of accuracy at low tensions. The Wheel Fanatyk is not as adept over 120kgf (works but less well) but it reads low tensions precisely. This matters if you build 11 speed Shimano or Campag wheels with thin, aero spokes. The left sides of those wheels are at such low tension that DT can't read them. So, if you own one, you also deserve a Wheel Fanatyk if only for the reason of low tension.

There's still a good argument for a Park or Wheelsmith tensiometer (remember those?), because they're cheap, numerous, and rugged. Field mechanics, in particular, try and keep their gear light and minimal. A simple Park TM-1 may lack some accuracy but easily survives an unpadded trip in the box of wrenches. Another reason to own multiple tools is calibration. Test them against each other. Learn what you're reading and to appreciate each for its strength.

We keep a calibration fixture to support Wheel Fanatyk Tensiometers. It's built around a Dillon Force Gauge. Don't try and use one that has not been recently calibrated. Today, there are digital versions if you are inclined. Think about sending your tool to us for calibration or, better yet, make your own. You can just hang 100kg from a single spoke beneath a tree. It doesn't have to be complicated, spoke don't lie.
Remember FSA tension gauges?
A really nice development is the work of Ryan Kereliuk in Calgary. He's a veteran wheel builder and talented IT guy. He offers a utility that works with our tension gauge to record and map tension. See his utility here at Spokeservice.ca. Your browser runs it. Check it on the site. Click "initialize" and view the sample chart with demo values. Now click "visualize" and see a radar map of the tensions.
Print your map for posterity.
You can download it from the first page as a web page. An html file "SpokeService Spoke tension.html" and one folder "SpokeService Spoke tension_files" will appear on your computer. Now you can run the utility without a web connection. Click the html file and your browser runs it independently. 

What a super gift to the building community. I'm sure we'll be hearing more from SpokeService in the future.

Thanks, Ryan.