Wire spokes for bicycles come in three main types—straight gauge, single-butted, and double-butted.
Straight gauge (DT Champion)
Single-butted (Sapim Strong)
Double-butted (DT Competition)
Of these three, single-butted have been sleepers, hanging around in the fringes, not much used or discussed. However, their role is growing and they will inevitably become the workhorses of the wheel world. Why? Read more →
Much talk of rim washers these days. When to use them? Which are best? While seasoned builders have questions beyond this post, for the rest of us, here are some considerations about washers to keep in mind.
Washers are often invoked to prevent galvanic corrosion between nipples and carbon fiber. The materials of nipples (brass and aluminum) wants to exchange electrons with carbon fiber. Direct contact makes it easy for corrosion to occur.
Simply for the purpose of discouraging corrosion, are washers sometimes overkill? Some points on this topic: Read more →
To build a wheel you must measure your hub and rim to determine spoke length. The better your measurements, the more accurate the spoke length prediction. Here’s a tool to make that easier.
Here is a definitive anti-friction, anti-vibration treatment for spoke threads. Apply to clean threads like paint. Allow to dry, then build and ride, reaping benefits beyond the reach of other products.
Why FIX?
Available in 15, 30, and 60ml bottles with instructions. For OE quantities, please inquire. 15ml fixes about 75 wheels, 30ml~150 wheels, and 60ml~300. Each bottle comes with a handy York tip that, if clogged, can be easily cleared with a spoke. We use LPDE extra soft bottles for easy dispensing.
Each experienced builder prefers a particular spoke thread treatment. For many, FIX is the hands-down best and yields the most luxurious and effective building experience. Imagine nipple adjustment at high tension with a smooth, almost hydraulic feeling.
High performance and heavily used bicycle wheels need nipple thread treatments. Here are some popular thread solutions and considerations.
For many experienced users. pro’s outweigh the con’s for each of these methods, There is certainly no best way to address the challenges of corrosion resist, building friction, and vibration loosening. If you, like me, prefer FIX, then you are willing to master its application so it does not add excess time. It offers the pleasure of super low thread friction, compatibility with any lubrication before or during the build. Once you have been spoiled, it’s hard to go back to any other thread treatment.
The chart below shows the relationship between nipple friction and spoke tension. For the sake of discussion, only 3 curves are showed— a FIX coated thread, an oiled thread, and an oiled and Loctite treated thread. Granted, this chart is not literal but it’s meant to convey a relationship.
A wheel needs some (hopefully small) friction at zero tension to resist vibration induced loosening. However friction should be as low as possible in the rest of the tension range, especially the tensions encountered in building.
You can see how a FIX treated wheel would be a delight to build and easy to adjust even at finished tensions. I trust your choice for wheelbuilding thread treatment, but maybe it’s time you tried another idea!
Click here to download a users guide.
October wheel building class in Port Townsend,
2 days + 6 rims and hubs + 192 spokes + 1 jolly teacher + 6 determined students (with an age range of over 60 years) = six excellent wheels and six future master builders!
Thanks to all who contributed to another successful Port Townsend Cycle School program!
The goals of wheel building and racing are the same—speed and efficiency. I am not a fan of most side stressing schemes for wheelbuilders because I believe they add time but not quality. The intention is noble—to make wheels more stable by relieving pent up stress in the freshly assembled structure. This is often done with the wheel supported at the rim on a table and a piston applying side load to the hub or all spokes facing the piston. This isn’t a cheap or compact tool. Granted, some of their users are very smart but… Read more →
A severe side (lateral) load on a bicycle wheel is bad news. Wheels are strong for radial (vertical) and torsional (twisting) loads but vulnerable for lateral. Fortunately, high lateral forces are uncommon with single track vehicles that lean through turns. Still, they account for most wheel failures and the actual dynamics remain poorly understood by many.
Let’s examine an extreme lateral load and discover how a wheel responds. How can a tensioned structure with balanced, triangulated bracing warp instantly into an unrideable potato chip shape?
Familiar shape with a bit of frost.
A lateral force usually arrives from the tire-ground contact, perhaps from skidding. The load moves the tire to one side which, in turn, pushes the rim to the side. The rim resists the force with both bending and torsional stiffness. The force is felt by spokes in the immediate region.
A spoke on the the force side tends to maintain its tension. A spoke opposite the force loses tension. The rim does not budge until the opposite side spoke reaches zero tension. At zero tension (all within milliseconds) all forces still balance out, and the rim is undeformed.
lateral load sequence
Once the opposite side spoke buckles, the rim begins moving. Would be helpful if the force side spoke, tight from the beginning, could increase its tension to resist the force. However, due to the low relative strength of bicycle rims, the rim begins moving away from the load in an arc whose radius is the force side spoke. The rim section swings at the end of the force side spoke as a yo-yo swings on its string going “around the world.”
Bent!
In practice, the force side spoke cannot increase tension to keep the rim stationary. The rim is too elastic and swings rather than remaining the same distance from the wheel’s theoretical center. In this example, the lateral force is extreme and our wheel now has a pronounced side bend at the site of impact. Neighboring off side spokes are unloaded as the rim moves their way. Their reduction in tension makes for a positive push that creates two bends that are reverse of the side load. Such “wings” also occur next to broken spokes.
Depending on the magnitude of lateral force, the flexibility of the rim and the amount of spoke tension; a sine wave can propagate around the wheel, driven by the reduction of spoke tension in half, or more, of the spokes. All energetic states seek a lower potential. The loss of spoke tension drives the sine wave, bending the rim into a potato chip shape. This has been triggered by the initial extreme lateral force, but the eventual collapse is an implosion of the tensioned structure.
© The Bicycle Wheel, J. Brandt
This potato chip shape, also known as a pretzel or taco, is technically a hyperbolic paraboloid. You can trace the edges of one on the Dumbo ride at Disneyland. When Dumbo swings low, its radial arm acts like a spoke that is maintaining tension. Swinging high is the same, but like an opposite side spoke.
Dumbo rises and falls as the ride rotates.
Hyperbolic paraboloid—Wikipedia
In wheels with extremely springy rims that do not easily take a permanent set, a potato chip wheel can sometimes be fixed by banging sideways on the ground. A reverse extreme lateral force can cause a sine wave that neutralizes the deformation. It’s a chancy strategy but if you witness one, you’ll know it was special. Steel and wood rims are better for this than aluminum or carbon.
If you travel around the rim like a bug (or Dumbo) it will be obvious the rim is deformed left and right but also twisted. It’s a torsional deformation, not simply left-right. Rims with great torsional rigidity resist taco shapes much better. Torsional rigidity increases as the 4th power of the radius of the largest inscribed circle that fits in the rim section.
The rim above (from 15yrs ago) can fit a large circle in its cross section, giving it extraordinary torsional rigidity. It is nearly impossible to twist into a taco shape. It’s not just the little dude inside making this rim strong. Many deep carbon fiber rims have high torsional rigidity. Pushed by an extreme lateral load they either bounce or break. Notice how many of today’s more enlightened rims feature large open space in their profiles? Good design!
A taco wheel often displays four lobes, two in one direction, two in the other; and one is usually larger than the others. Safe to assume the extreme side load was delivered at this spot and the other three lobes formed as a consequence. Trying to true this wheel is wasted time if the rim has taken a permanent set.
Loosening spokes will reveal how extreme the bend is. Once de-tensioned, the true rim shape appears. If you must use the rim again (think: remote location expedition) try and make it as straight as possible without spoke tension. Be very careful to not introduce kinks or dents as you lever the rim to flat. Once the rim is flat, it will support spoke tension again and have no residual tendency to return to a taco. Truing without first bending the rim makes an unbalanced structure prone to deform again.
Before we leave the world of tacos, pretzels, and potato chips, let’s notice one further way a wheel can assume a multi-lobed deformation—excess tension. A rim can only support so much total tension, in proportion to its mass and shape. We used to build a favorite rim to 100kgf per spoke, with 36 spokes. The same rim with 48 spokes could not support 100kgf on each spoke.
An over tensioned wheel can “pop” suddenly into a wavy pattern. It’s the same principal as extreme side loads. Such a deformation will have many (not just 4) lobes, each small deflections. If you lower the tension total, with luck, the rim may behave as if nothing happened. It was just trying to reach a lower energy level. In its wavy state some spokes lost tension, others maintained. The total was lower.
Whether you ever undertake such truing, it is important to understand the forces involved. A wheel can suddenly become a taco shape with an extreme side force. In slow motion, this begins at one spot and a sine wave of deformation travels around the wheel often leaving a 4-lobed taco shape.
When it comes to metal bending and tension, most everything is reversible so, even if impractical, such wheels can be repaired. With these principles in mind, try your hand at it. You may not succeed but the exercise is always informative. Experience at the fringe of possibilities is what makes developing world bike mechanics so resourceful. Hone your own skills, don’t let them have all the fun!
Trick procedures are as important to your tool box as the individual tools. Please share them whenever possible. In that spirit, check these:
Proper dial indicator use
Plunger dial indicator
Indicators magnify movement and provide numbers to better judge trueness. However, your standard dial probe indicator is not made for rapidly moving surfaces. Even when an indicator is fitted with a bearing, the measure surface (rim brake track or edge) should only move slowly for two reasons:
1/ The probe is not designed for sideways force. Its accuracy is wrecked if the probe bushing wears.
2/ The probe return spring is as weak as possible. Consequently the probe can jump off the test surface with a tiny bump and vibrate with a pattern of roughness. To navigate a rapidly moving surface, the probe would need a strong spring and a dampening mechanism to maintain contact.
Spinning a wheel on a truing stand is normal when a light gap is used to watch trueness. A gently spun wheel can turn at 60 rpm. With a full sized wheel, this is 4800”/min, the same as a 1/4” drill at 6,000 rpm. This is not slow speed!
So, move your wheel at any speed for visual truing but turn it slowly with dial indicators. Don’t let your measuring instrument use cause machinists to cringe!
Bearing play
Builders deal directly with hub bearing play. Play interferes with truing, even when it’s too little to bother riders. In some hubs, play can be adjusted to zero for the build and then returned to the recommended amount for use. In most cases, however, it must be tolerated.
How to measure play? Axle play is magnified 10X at the rim but quantifying is delicate work. Hold the rim where a dial indicator is located. Give it a slight lateral force, left then right. The wheel is easy to flex so your finger force must be extremely light to reveal bearing play only.
What is reasonable? No single answer exists for all wheels. One number many experts would approve is 0.008” (0.2mm) at the rim (TIR—total indicated runout). Such a reading at the rim can be produced by less than 0.001” (0.02mm) movement at the axle. These numbers are at the very extreme of manufacturing tolerances for consumer products. More accuracy may be needed by NASA, but not us.
Heat Guns rock
Trusty heat gun
A must around any shop is your standard 1500W heat gun. Like anything with voltage and heat, special care is important—flammables must be far away and good ventilation present. Some of my favorite uses:
1/ Removing adhesive vinyl stickers from nearly anything. Vinyl stickers lift off effortlessly with the right heat. Use less until you discover the perfect amount. Be careful not to damage your surface.
2/ Heating metal so stuck screws or bearings can be removed. Heat makes metal expand, each material with its own CTE (coefficient of thermal expansion). Aluminum expands much faster than steel. But even in steel-to-steel assemblies, a larger unit will expand faster than a smaller (like a stuck screw). Frozen nipples are a good example.
3/ Drying touchup paint, adhesives, spoke prep, rinsed chains, etc.
4/ Removing old sewup glue from metal rims. Heat then scrape or wipe with steel wool.
5/ Lubing old leather saddles. Apply a preservative cream or wax, heat the area and watch the saddle inhale the lube. Be sparing, it’s easy to make a crispy old saddle way too oily.
6/ Paint removal where the substrate can take the heat. This works on metal or wood. Paint softens before burning and can be scraped or wiped off.
7/ Applying shrink wrap. Handy shrink wrap is available is many colors and diameters, used extensively in electronics. Find ways to employ it on bikes—bar tape or cable end finishing, for example.
Got some other tricks? Wheel specific? Please share!
Plucking spokes while building is a time-honored technique for tension appraisal. It’s especially effective for judging if neighboring spokes on the same side of a wheel are at different tensions. The more even the tension, the more stable and long lasting the wheel. For more on the acoustic tension method, check here.
30 years ago, visitors to Wheelsmith would remark that we sounded like a harp tuning studio with musical notes in the air as builders plucked spokes to confirm or correct their hunches about the best adjustments to make. In those days we used fingernails to pluck and it wasn’t so easy for everyone.
Today, plucking continues in popularity among builders who want to make accurate adjustments and move faster through builds and, guess what, guitar/banjo picks are being used. Here, I show how to compare the tensions of neighboring spokes by plucking them.
After Jude Gerace told me she used banjo picks, I tested every finger pick I could find to determine the best for wheelbuilding. Here’s an assortment:
© Fred Kelly Picks
The winner was no contest: Fred Kelly’s delrin Freedom Pick does it all. They are the white one’s above. This pick can be fitted on your spoke wrench hand’s ring finger. There it is neatly out of the way for truing and handling. When you want to establish tone by plucking, the pick acts like a reinforced fingernail. Pluck as hard and as often as you want without strain. Delrin produces a clearer, more spoke-only sound than a metal pick, which invites harmonics into the tone.
The delrin Freedom pick.
This pick is just one of 58 pick styles Mr. Kelly makes in Grayling, Michigan. He’s been playing for 60yrs and making picks for 40. This one takes the place of your fingernail, has a comfortable yet secure fit to your finger, and is completely adaptable for a personal fit by exposing them to hot and then cold water.
We stock medium and large which fit 90%+ of wheel builders. Try one as soon as you can. Buy two and keep what fits best. You’ll never go back to bare nail plucking.
The eminent Fred Kelly.
Thank you Mr. Kelly!
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?
