To properly build wheels, we need to understand basic concepts of mechanics and how they relate to our bike wheels. We need to have a firm grasp on how screw threads work in relation to nipples and spokes; we need to know how to combat friction, and the mechanics of what it takes for a wheel work, and to keep working for an acceptable period of time.
For this Wheel Builder column I’m going to go over some standard wheel building and general workshop practices that are crucial to our goal of well-built, and well-maintained, wheels. These practices could mean the difference between wheels that need constant attention and wheels that never need re-truing or re-tensioning throughout the life of the rim, or wheels that never break spokes.
Concentricity on the central plane
Asthe rim of a wheel is supposed to be concentric to its hub, and because the wheel has to run on the center line of the bicycle, it is very important that we construct the wheel – from the beginning – with this in mind. In the first stages of building the wheel and during any stage of maintaining a wheel, we need to be aware that this “central plane and concentricity” has to be developed and maintained.
For instance, when we are initially tensioning the spokes, we have to screw the nipples down as evenly as possible to place the rim concentric to the hub, or we will get hops in the rim that have to be removed.
To achieve this we have to screw the nipples down in equal stages, going around the rim for one full rotation and without missing any spokes. I take them down in two stages: the first stage is to “3mm of threads showing,” and the second stage is the “no threads showing” stage. Ensuring that all the nipples are screwed down evenly ensures that the rim is concentric with the hub. For further tensioning, we have to count the fractions of turns that we are applying to the spoke wrench, as we have no other visual record.
During early tensioning, the rim must also be “dished” to rotate on the center line of the bike’s frame. (Definition of dish: to center the rim between the hub locknuts.)
Nipple and spoke threads, like almost all threads on bicycles, should be lubricated to allow proper tension to be achieved without dry threads binding and sticking due to friction. While specialized lubricants abound for almost any mechanical device, nipple and spoke threads have fairly simple needs and therefore almost any form of lubricant will work just fine – oil, grease or a dedicated thread lubricant, like anti-seize compound (which is my favorite for spoke threads).
Dip the spoke threads (you can do each group all at once!) into a 1/4 inch (.64cm) of oil in a tiny container and then let them drain on a piece of paper towel. If using anti-seize, paint the treads with the compound using the brush that comes in the can or a soldering acid brush. Not much oil or compound is needed – just enough to fill the fine threads.
Combination thread-locking and lubrication products and mechanical self-locking nipples exist, but I’m not a fan of either as I’ve never needed them. I’ve found that “sufficient tension” is enough to stop nipples from unscrewing.
Nipple seat lubrication
To prevent binding and galling between the nipple shoulder and rim hole (or rim ferrule), the rim hole should be lubricated from inside the rim. You can use the above lubes or grease for this step. My favorite is to dip a Q-Tip into the grease can and apply the lube to the nipple seats. Or, when the wheel is assembled and before any tension is applied to the spokes, one drop of oil can be applied to the nipple shaft where it exits the rim. It will then run down to the nipple seat.
As I usually use nipple washers on rims without ferrules, I need to get the lube between the nipple and the washer. I apply it with a needle oiler when the wheel is assembled and before spoke tension is applied.
Spoke length calculators
Correct spoke lengths are crucial for proper wheel building. Due to the plethora of combinations of rim dimensions, hub dimensions and spoke crosses, spokes come in a multitude of lengths. As their length for your wheels is critical to within +/- 1mm (plus or minus one millimeter) it’s crucial that we calculate the exact lengths needed.
Whole chapters in wheel building books are devoted to this very important step, and I touch on the important points on my web page, but I’ll mention these tips:
- Choose a spoke calculator. They can be found online, and my favorite is right here – www.wheelpro.co.uk/spokecalc/. Chose a calculator AND use their system of measuring rim ERD (Effective Rim Diameter) and hub dimensions, as their calculator will be configured around their way of taking measurements. Be wary of any that don’t show you how to take measurements.
- Measure the parts yourself and never rely on dimensions supplied by others – even manufacturers! Many times, they have been proved to be incorrect, and you will be the one who suffers.
- When you use a spoke calculator, you will end up with spoke lengths in millimeters and fractions of millimeters, and you have to round the numbers up or down to the closest spoke length available. Most spoke retailers stock spokes in odd or even lengths; rarely both. And that’s OK, as we do have the holy grail of +/-1mm to play with. It doesn’t seem like much tolerance, but it works just fine. Just don’t go over 1mm when doing the rounding of the numbers.
It’s normal to require 2-3 different spoke lengths for a pair of wheels, and it’s rare if we can get away with just one length. No matter, as all good spoke retailers allow us to buy whatever amounts of spokes that we need. Always get 1-2 extra spokes per length and label them and store them away for emergencies.
- If you’re going to use nipple washers, add their thickness to the rim’s ERD – my washers measure 0.7mm each or 1.4mm for two (when measuring rim diameter!).
I’ll continue this look at basic concepts in the next Wheel Builder, covering spoke twist, how to identify spoke twist, and stress relief.
Q&A: What to Take on a Tour
What are your thoughts on wheel maintenance while on tour; that is, with a minimum of tools and an eye to prevention, as well as fixing wheels on the road? – Blaedel, from the Comments page
My answer has to begin with a question. Do you break “lots” of spokes on your tours? If the answer is yes, then maybe the wheels are not up to the job expected of them, either in terms of strength or build quality. If you don’t break lots of spokes, and this is then just a general question, I’d prefer not to lug around the necessary tools (chain whip, cassette tool, tool wrench and spoke wrench) and just take two of each of the correct length spokes with me. If I was unfortunate enough to break a spoke, then I would seek out a bike shop to fix it for me and at least I’d have the correct length spoke for them to use.
I’d carry the ultra-light Spokey spoke wrench for emergency spoke breakage – which would allow me to true the wheel enough to get me to a bike shop. For touring wheels with lots of spokes (32, 36?), this is quite possible.
For prevention, I would make sure the wheels are properly built before the tour began – by having an expert check for sufficient spoke tension and equalized tensions. And I’d have the rim checked for tiny spoke hole cracks.
Mike Tierney writes The Wheel Builder column for RBR. Read his full bio. He is a life-long cyclist from the UK who has spent most of his adult life in Canada. Mike has been a passionate home wheel builder for the past 52 years and specializes in taking the mystery out of wheels and wheel building for Newbies. Hundreds of cyclists have built their first wheels with online help from his wheel building website, MikeTechInfo.com. Send your questions about wheel building and wheel maintenance to Mike at firstname.lastname@example.org.