One of the most memorable characters in our cycling scene of the early 1970’s was Phil Wood who, with his wife Vada and manager Bern Smith, pioneered the modern use of cartridge bearings in bike components. Here Bern recalls some of the special challenges:
Here’s an introduction to the complexities of specifying, testing, purchasing, re-testing, lubricating and assembling bearings. Some of this will be pretty pedestrian to folks with working knowledge of bearings, but there’s plenty other facets to it.
In the earliest days of Phil Wood & Co. circa 1972, once Spence Wolfe had convinced Phil to manufacture some maintenance-free hubs, and they agreed that 50 pairs would be the most they could ever sell, Phil started testing bearing and lubricant samples. He settled fairly quickly on a single domestic manufacturer of bearings, but the grease samples were…disappointing…
He found ‘waterproof’ grease that dissolved in water, grease that absorbed water, swelled up and forced itself out of the bearings past the seals, and other oddities. Eventually he found a product from a local (Bay Area) supplier that was something of an oddity itself – the manufacturer produced only very small batches of this particular grease, and only occasionally. It was somewhat inconsistent in texture and color. But after Phil consulted with them a little, they changed the mix, and after that it worked really well in full immersion salt bath tests.
And it was green…
So we were off and rolling…
We specified that grease to the bearing manufacturer for lubing at their factory. Then the fun began.
A tangent (and a quiz) are required here.
• What is the highest rpm a bicycle bearing is ever likely to spin?
• How many rpm’s is a regular radial-contact industrial ball bearing typically tested to maintain without burning out?
• How hot do you think bearings get at max rpm?
• What causes that heat?
• What exacerbates it?
…and what is the maximum percentage fill of grease in the bearing assembly cavities (those gaps between the bearings, their retainers, and the seals) that most any manufacturer will agree to?
Back to the early bearings. We found soon enough that our idea of how much grease a bearing should have in it was vastly different from what the bearing suppliers were willing to provide. Typical over-the-counter industrial bearings are filled ~25% full with grease. That’s because those bearings, in a normal installation (an electric motor, say) might run as high as 10,000 rpm – 10 times higher than a bicycle bearing will ever spin. A bearing running at 10,000 rpm gets hot – really hot – from friction, and hotter still if it has too much grease in it (retaining heat in the assembly). Too much grease meaning anything over about 25%.
We specified 95% fill because our tests showed that provided satisfactory water resistance in the extreme tests we put bearings through. But the suppliers refused, citing product liability, and other not-pertinent reasons. So we had to lift seals and add grease to each bearing. That probly doubled our bearing cost.
At least we were getting good bearings…until…batches started arriving from the factory with large grit, wood chips, crystals and other unknown stuff. We rejected lots of bearings. It got so bad that, in the final batch we rejected from the original supplier, most of the bearings would not rotate. Now, there’s a handful of things a bearing needs to do, but above all…
Eventually we found a (foreign) company that produced consistently good bearings for considerably lower cost than the others. Were they eventually prosecuted for dumping bearings in the U.S. to put domestic factories under? Another story for another time…
Then the grease started to get weird…
As you might have guessed, as we grew more comfortable with the grease we chose, we had an idea that maybe we could use that grease for other purposes, and maybe other folks might like it as well. In particular, we felt that the lovely deep green color itself could help sell the stuff, and we settled on a slogan – ‘It’s Green!’. Anyway, we asked the manufacturer about making larger batches, that we could repackage from 55 gallon drums into 3oz tubes. They asked how much we might ever sell…
Each time we got ready to order grease for repackaging, I went to the lab at the lubricant plant and inspected samples. They had a few minor problems and we rejected some batches – turns out that the grease mixing vat was used for several different products and occasionally did not get cleaned out completely between product switchovers. Eventually the plant assigned a mixer for this grease alone, and things smoothed out.
At one point, after about 3 years without a single problem, I asked Phil if maybe we didn’t need to go to the plant to check the samples first. We looked at each other for a moment and said simultaneously “Check the grease”…So I drove to the plant and met the project manager in the lab, where he pulled out the latest sample. It was a beautiful, deep black. Lesson learned the easy way for once.
Years later, after the project manager had retired, I related that story to his successor, who laughed, and said “Oh, yeah – he was colorblind!”
In Part 1 we saw rims deform from tire pressure causing spoke tension drop and discussed the role of tire dimensions, noticing road tubeless clinchers have the most potential to amplify tension drop.
In Part 2 we established that design, not manufacturing inconsistency, makes for odd matches and extreme tension drop situations.
Here in Part 3, let’s ask what builders can do to minimize negative influences of tension drop. After all, builders invest spoked structures with tension and answer for wheel performance. Read more →
Part 1 showed how clincher rims can alter spoke tension when tires are inflated:
(1) Outward splaying of brake tracks, changing the rim shape, dropping spoke tension.
(2) Inflation pressure down on the rim bed, a constricting force that shrinks the rim causing measurable tension loss.
Tension loss can be confusing to wheel builders following tension recommendations from rim makers. We need to know why this happens and when to worry.
Here in Part 2 we explore how tires, independent of inflation, affect this dynamic.
First let’s review tire and rim sizing for those less acquainted. Why are they made to the sizes we see?
There’s hardly a more multi-tasking structure in all of engineering than the bicycle wheel. All its components are mutually dependent and interactive. Then no surprise tire pressure affects spoke tension. Here’s first of a 2-part discussion of this phenomenon, that is reaching a worrying scale in today’s wheels. Inflate a clincher to 90psi (6 bar) and you may see tension drop 20-50%. Why? Is tension drop bad? Should wheels be over tightened to compensate?
If wheel building were introduced today, but as a game, would it be popular? No VR but plenty of action: thrill of pursuit, unforeseen obstacles, counter moves by invisible players, presence of a formidable adversary, satisfaction of success.
Plus, the outcome can be ridden. Ka-ching! Wheel building has always been a game and its unpredictable challenges attract agile problem solvers. For many, the challenge of wheel building is compelling. Dependent variables exponentially increase system complexity. Tensioned wire wheels are elusive, almost intelligent, always unique competitors.
Wheel builders are not whiners by nature. The challenges of the craft are enough to turn arrogant builders, humble and most whiners into learners. Consequently, many nuisances of our work go undiscussed. Today I present two solutions to annoying personal peeves.
Oiling is a big part of bicycle mechanics and wheelbuilding. We drip, squirt, inject, mist, and drown bicycles with a variety of lubricants. I’m fed up with second rate delivery of these. It’s either aerosol can or disposable squeeze bottle. Neither meets my standard for precision, ergonomics, reuse, or aesthetics. A plastic bottle with a small hole will drip oil when you point and squeeze but this is the 21st century and we have a long tradition of clever oilers that seems bypassed in this era of consumer packaging.
Presenting the Wheel Fanatyk Oiler. This is an established but too rare design that’s perfect for bike mechanics. A 250ml (8.5oz) capacity means you can dispense liberally if needed. A broad base gives the can stability. Three ball-check valves and two staged cylinders allows enormous pressure. A brass tipped, rigid spout gives pin point precision. Its oil gathering sump carries a filter to keep the mechanism clear and the oiler stays primed for weeks.
Transfer your favorite formulas to these bottles and lube like a sharp shooter. Label each oiler with a sharpie pen on masking tape. At just $4.90 each, you can afford as many as needed. Escape the insult of consumer quantity squeeze bottles with fall off spouts and throw away pumps. Use the Wheel Fanatyk Oiler and up your game from consumer clumsy to professional! Check here.
Second peeve of mine is the scarcity of adequate magnifying glasses to examine fastener threads (or look for splinters). Spoke threads, in particular, are valuable to study especially if you’re mixing brands, using re-threaded spokes, or cutting your own.
The Wheel Fanatyk inspector is an upscale version of a device that evolved in the fabric trade. A thread inspector is a lens mounted the exact distance over fabric so no focusing is needed. Threads can be counted to make sure knitting machines are correctly adjusted. For us, this is the perfect setup to study small, especially spoke, threads.
The inspector’s metal body has a screwed on bottom cover allowing access to watch batteries that power three brilliant LEDs. A 30mm diameter 20X lens gives a broad field of vision. You’ll be astonished and informed by what you see. Don’t struggle with miss threaded small screws and spokes when you can identify their problems and move swiftly to a solution. The inspector is shipped with a second set of batteries. Check here.
Check a few of these thread forms. To the naked eye, they look about the same. Time to stop taking them for granted or cross-eyed squinting. Our thread magnifier will set you free and guide you to insight that today’s professional needs.
The Oiler and Inspector belong in any sophisticated bicycle workshop and we’re going to ship them with every Morizumi SCT machine starting next month. In addition, each SCT will also come with a stainless steel base pan. Ours is a heavy gauge (10oz), highly polished pan in 302 stainless, designed as a surgical tray. We cut three holes necessary for mounting under the SCT. With a base pan, the SCT can receive the ample oiling to keep it running smoothly. Excess gathers harmlessly in the pan, to be wiped clean periodically. Our heavy duty base pan is available for current Morizumi users at $30.00. Check here.
A few images of the SCT with its pan and new accessories:
Removing tubular tires should be easy. Getting the tire off the rim should not require gorilla strength.
Over the past few years a new issue has arisen. Pulling tubular tires from carbon fiber rims can cause delamination of the rim bed. Creepy, to say the least. Is this normal? What is going on? What to do?
Carbon delamination – please, no!
No carbon rim maker wants to hear about structural delamination during tire removal. Every design effort is made so it cannot happen, as it is impossible with aluminum rims. We all have the same objectives. Under normal circumstances, the inter-laminar carbon layup strength is greater than contact cement on the surface.
Is the delamination important?
Plies (layers) of carbon cloth are extremely thin. Departure of several plies is visually dramatic but may not be a structural problem. It all depends on the design. The rim maker is your only reference. Hopefully, the departed plies are sacrificial, intended to be rugged and expendable.
Gluing is improving
We are seeing a growing appreciation for tire gluing integrity. More than ever, mechanics are using best practice for achieving strong bonds. In the past, when glue integrity was mainly a concern for high level road racing, technique could be less rigorous. Cyclocross, in particular, sees weird rim-to-tire combinations (where bed and tire form do not closely match), suffers water contamination (weakening bonds), and uses very low tire pressure (lower pressure = less tire grip to assist the glue). CX gluers are doing really good bonding.
How to minimize risk when removing a tubular
First, deflate the tire. Air pressure makes the tire grip the rim. Not enough grip to ride without glue but enough to interfere with removal.
Next, try and pry a small section of tire free. Use all your thumb and grip strength. If the tire is properly glued, you will fail. Well glued tires cannot be removed by hands alone. Still, give it a try. After working a 10cm section on one side, flip the wheel over and try opposite. With luck, some of the tire base tape will begin releasing from the rim.
You’ll then need a narrow pry tool, such as a slotted end screwdriver, to push into the glue and separate the tire from the rim. Your goal is to push the screwdriver (or equivalent) all the way through between tire and rim, from one side to the other. A steel tool like this can damage the rim or the tire. Use it gently, pushing carefully, wriggling small amounts, separating the tire from the rim in tiny bites.
Once you achieve tool insertion, replace the slotted (sharp end) screwdriver with a round, Phillips type. My best luck is with a blade about 6mm (1/4″) in diameter. A larger diameter dowel works but the rim and tire prefer the small steel shape. While seated, place the wheel between your legs, with the screwdriver handle in your dominant hand. I am right handed, so here the screwdriver handle is on the right.
Orient the wheel so the screwdriver is at the top. Pull the driver towards you with both hands while you rotate it clockwise (viewed from the right side). Pulling while rotating advances the blade towards you, rolling against the sticky tire bed and skidding against the smoother rim.
This rolling requires a strong turning hand (right for right handers) and a firm pull on both sides. The tire bond is no equal for this rotation. The tire will begin to separate from the rim as you pull and rotate.
You can also use a dowel but the screwdriver blade offers less resistance and a better separation angle. The glue joint is more susceptible to the small radius of the metal driver.
You’re inducing a glue joint failure and the angle of separation is better for the small rotating blade than a larger rotating dowel. We’re inducing a cohesive failure with glue remnant on both rim and tire, handy for future gluing.
As soon as enough tire is separated, pull the tire from the rim. Pull in the plane of the wheel so the tire is doubled over as it leaves the rim. This minimizes base tape separation as you pull it from the rim.
Back to our carbon rim problem, Using the small diameter metal rod induces cohesive failure and minimizes the chance of rim delamination. The final tire removal (over 50% of the circumference) is done without the metal rod, just arm strength. Doubling back the tire as it peels reduces delamination forces.
More than a few mechanics note that heat aids tire removal. At 70C (160F) rim cement is liquified. At 40C (100F) cement is substantially weaker than on a cool day. Using a heat gun to warm is impractical. A wheel is large and sheds heat. At least appreciate this principle and let wheels come to the highest available temperature before pulling tires.
Throughout tire removal, proceed slowly and watch the tire carefully. Stop if anything does not proceed smoothly. Some tires will disintegrate upon removal but it’s rare except for limited use track tires.
There is much to tire mounting that you must know. Demounting is not the opposite of mounting. Great instructions are available in many places: mine (here and here), Calvin’s, and Chip Howat’s scholarly works, among others. Gluing tires is done thousands of times a day and each job carries immense responsibility for rider safety. Learn your stuff and be part of the reason cycling is known as a healthy sport.
As ever, practice is the best teacher. Try different techniques, pester experts with questions, listen to all opinions, and develop dependable techniques. There are too few tubular gluing guru’s. Please join this club!
One of the many reasons we changed indicators to Mitutoyo is their host of download options. A single cable will connect the digital tool to any laptop via USB. The system is complete and fast. Best, it’s compatible with the SpokeService tension utility.
Now go one step further and incorporate a foot pedal. The foot pedal system is three components connecting the tensiometer to a computer.
Recommended by Mitutoyo for this application, the component kit sells as a set.
Best used (but not only) with the SpokeService.ca utility where, once started (and until you close the tab), the software resides and runs inside your browser; no web connection required. However, any spreadsheet program will work. The advantage of SpokeService:
With your cursor in the SpokeService utility active cell, place the tensiometer on a spoke. If the tool does not read zero, tap the foot pedal. Now release the tool, creating a deflection, and tap again. The program automatically sends the correct output number. This double tap routine becomes a reflex and tensions can be sensed and entered with great ease and speed. The cursor knows when to advance. If the tool does not need zeroing (often the case), just tap once. The software knows what is a number to be deducted and what is an actual deflection reading. Foolproof and fast. Watch a demo here.
Prefer not to use the SpokeService utility? Begin by placing your cursor in any spreadsheet active cell. Apply the tensiometer to a spoke, zero with the “Origin” button on the indicator, release the tool to see the reading. Tap the foot pedal once to enter the reading and the cursor advances.
Such ease of use and accuracy has only been available in industrial building systems often costing in excess of €10,000. Wheel Fanatyk is proud to be associated with a wheel building data collection breakthrough. Once you’re accustomed it will be hard to imagine building without.
To buy, check here.
A new product and the return of an old favorite, what good news for the coming season!
We’ve added Pedro’s new spoke wrench. Three sizes, a delightful and original design, likely to become many builders’ go-to wrench. Pedro’s stuff is always a pleasure. Uber sturdy construction, no shortcuts, and trademark screaming yellow…what’s not to love.
Three sizes cover the range for 14 and 15G nipples: 3.23, 3.30, 3.45mm. Each tool features a reversible hardened steel insert offering a fast on and off, straight side opening and a 4-side drive, diamond shape.
Best news ever is the return of our nipple shuffler trays. While most efficient nipple lubing uses a strainer, pre-oiled nipples tend to drip. When you sprinkle them into your shuffler to begin lacing, a catch tray would be handy. We ran out last year and it’s been many months without.
Your shuffler sits up on the corner shelves. The wood loves oil, so everyone is happy. Just received 50 from Jon, a variety of woods, all magnificent. You’re welcome to make a request in the “notes” area at checkout but I’ll not be listing or selling them by species.