Wheel Building: the Musical, Part II

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As I have written before, wheel building is now considered an optional skill for most cyclists.  However, if you ride a vintage or custom bike, or enjoy doing your own wrenching, acquiring the knowledge to build your own wheels can prove invaluable.

Vintage bicycles often need a replacement wheelset of the same era, which requires sourcing period hubs and rims.  Or, the original wheelset may need an overhaul, with new spokes.  Because older bicycles have narrower rear drop outs compared to modern bicycles, learning to build wheels can help you complete a restoration project that would otherwise be impossible, as new rear hubs generally cannot be used for older machines.

Serving as the inspiration for this post, the rear hub on my winter bike needed to be replaced – a Quando/Quanta hub whose cartridge bearings had failed.  The wheelset is one that I previously built and served as the platform for “Part I”.  To replace my failed hub, I ordered a new Velo Orange Grand Cru 126mm hub with freewheel threads and 36 holes – exactly what I needed to complete my task.

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Materials and tools needed.

First of all, let me say that there are excellent resources on the web and in print for anyone who wants to learn how to build bicycle wheels.  Many years ago, I built several wheels on my own, with no classes or any training, by following Sheldon Brown’s wheel building guide and using Jobst Brandt’s book, The Bicycle Wheel, as a technical resource.  Those wheels are still perfectly true and in service.  So, if you are methodical, patient, and not drinking or smoking anything while building the wheel, you may be able to be a completely self taught wheel builder.  However, I also later took several wheel building classes which helped with those little tricks and tips that only an experienced builder can show you.

I can’t say enough about Sheldon Brown’s online wheel building guide.  In it, you will find an overview of the process, a list of all the tools and materials you will need, and an easy and non-geeky step by step process which can instruct novices and experienced wheel builders alike. And, it is a free resource.  I printed out my copy years ago, but checking the link recently I see that it has been updated with new information.

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Spocal spreadsheet for VO Grand Cru hub and SunRims CR 18 rims.

Before starting you need to determine what length spokes will work for the hub and rim that you have selected.  You will need to take some key measurements off the hub, unless you are able to locate your hub in one of the on line spoke length calculators available.  If you are using a vintage hub, Sheldon Brown, again, has a helpful resource which shows you how to measure the key elements of your hub.  The VO hubs that I am using for this example, though modern, were not included in the Spocalc spreadsheet data base – which is a great tool developed by Damon Rinard.  Fortunately, VO’s website gave me all the measurements needed, so I plugged those numbers into the spreadsheet, as shown above, and that yielded spoke lengths of 260mm for the non drive side and 258mm for the drive side (for a dished rear wheel, the non drive side spokes will always be about 2 mm longer that the drive side spokes, due to the greater distance they must travel).  You will also need to take measurements from the rim you will be using.  If it is a vintage rim, it will not appear in data base of the spoke calculator you decide to use, so you’ll need to measure the effective rim diameter.

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Spoke Prep Instructions – not to be ignored!

I always use 14 gauge spokes (butted or straight depending on the application) and 2mm brass nipples.  Generally, I use DT spokes and nipples, which have a good reputation for reliability and strength.  The spokes, which are always under tension, need to have their threads treated with something that will act as a lubricant, and ultimately as a thread locker.  I use Wheelsmith’s Spoke Prep.

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You must follow the Spoke Prep instructions and dip your drive side and non drive side spokes into the solution, and then let it dry completely.  Since I was working outside to build this wheel, I put each set of spokes on a separate chair.  Drive side and non drive side spokes must not be allowed to mingle!  And it’s best to separate each spoke after dipping it into the Spoke Prep solution, so that when it dries you won’t have to separate it from the other spokes.  The above photos show the spokes before I have separated each one to dry.

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I haven’t invested in any high end spoke nipple drivers or spoke wrenches.  I use Park spoke wrenches, plus a square wooden handled screwdriver with a straight blade that I have filed slightly to a point, so that it will contact the spoke nipples with more gusto.  And, the square handle of the screwdriver makes for easy manipulation of the spoke nipple.

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The Key Spoke

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Setting up the Key Spoke for my hub and rim.

The night before, I got out the hub and rim to select the location of the Key Spoke.  By setting up the Key Spoke correctly, the hub’s logo will be visible by peering through the valve hole, and there will be no crossing spokes above the valve.  Setting up the Key Spoke correctly is the mark of a mindful wheel builder.

I used a water soluble marker to indicate which hub hole and rim hole were to be use for the Key Spoke (which I will later clean off). In my case, the SunRims CR18 rims were set up so that the Key Spoke hole was 2 holes to the right of the valve hole when looking at the rim from the right hand side.  The Key Spoke is a trailing spoke, meaning that it angles backwards from the hub when you look at it straight on.

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I lubricate the spoke nipples with a drizzle of automotive oil.  This helps the spoke nipples seat against the rim eyelets and move around as needed while you are bringing up the tension on the wheel.

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My VO hub looks very nice – it came packaged in this elegant black draw string bag.  A touch of marketing finesse. The hub is cold forged and then CNC machined.  Hopefully, the cartridge bearings were installed correctly and will last for many thousands of miles.  I wear protective gloves for the initial spoke installation.  Spoke Prep and automotive oil are bad things to have going into your skin.  Later, I’ll take my gloves off for the truing and tensioning process.  The night before wheel building, I re-read Sheldon and Jobst’ guides.  Since I don’t build wheels every day, it is important to refresh my brain with an overview of the process and of the physics and engineering concepts involved.

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The photo above shows the trailing spokes, which are inserted from the outside of the hub shell.  You start with the drive side spokes first (after inserting the Key Spoke), then move on to the non drive side.  Then you twist the hub clockwise as far as it can go.  The above photo shows my wheel after inserting the trailing spokes and twisting the hub clockwise.

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Now it is time to install the leading spokes.  These spokes are inserted from the inside of the hub and angle toward the front of the bike.  In a 36 hole 3 cross pattern, the leading spokes cross over two trailing spokes, and then are laced inside the 3rd spoke before securing them to the rim

Once that is done you have laced your wheel.   That is actually the hardest part of this process.  Now it is time to begin bringing up the tension on the wheel so that it can be trued and dished.

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A source of comfort is seeing that you have installed the Key Spoke correctly and can not only see the hub logo through the valve hole, but you can also see that the valve hole has no crossing spokes above it.

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Park Tension Meter

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Optional equipment

You should now gradually tighten all the spokes so that their overall tension is equal.  I follow the musical note method, by plucking the spokes, and bringing them all up to the same level.  Then it is time to true the wheel, then check for radial (up down truing), and check for proper dishing.  For this particular wheel, the wheel tension came up much quicker than expected, so I ended up backing down the spoke tension after checking the maximum tension for this rim. I use the “musical note method” to check spoke tension, but I also reference my spoke tension back to the rim OEM manufacturers specs, if those can be found.  If not, take your tension meter and check other wheels on hand (being mindful that rear wheels and front wheels may have different spoke tension, and that smaller diameter wheels will have higher tension).  If you have handled a lot of wheels, you’ll have a feel for proper spoke tension that will be confirmed by using a Tension Meter or a musical note.  If not, don’t panic. Rims can tolerate a lot of variance in spoke tension.  Mainly, you want to true the wheel, laterally and radially, and bring it into dish.  And, it is critical that you relieve spoke stress by mashing the heads of the spokes against the hubs and by pulling pairs of parallel spokes against each other.  Also, when you tighten spokes you need to be mindful of spoke wind-up – which happens when the spoke twists instead of the nipple threading into the spoke threads.  You can do so by holding a finger over the spoke while tightening to feel for this, and then backing off your effort slightly to unwind the spoke.

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Velo Orange 126 mm hub on SunRim CR 18 rims, 36 holes.

Now my wheel is built and its time to install the rim protector.  I always use Velox rim protectors for rims with double walls.  Be careful not to use too wide a size, as that will prevent the tire from seating correctly. Now, I look forward to installing the wheel and getting back out on the road.

Wheel Building: the Musical

Quando hubs and sun rims

Why build bicycle wheels when there are tons of inexpensive and well built wheel options out there in the marketplace?  Well, in this case I have been wanting a nicer wheelset for my winter bike.  It sports a mismatched and funky set that is old, pretty heavy, and is getting long in the tooth.  The bike, a 1987 Panasonic MC 7500, has 126 mm rear spacing and uses 26″ MTB rims (559 mm).  I didn’t want to spread the frame to 130 mm, and I have had these Quando/Quantum 36 hole sealed cartridge hubs that have been in my shop for a few years now.  The Quando hubs’ rear spacing is 126, and with their cartridge bearings, they should be perfect for winter riding.  Plus they are about as smooth as hubs can get.

I build wheels every now and then, so each time I do it I need a refresher course.  Since there are so many thorough, step-by-step resources available on the web, I thought I would use this post to focus on the practical side of wheel building, rather than science (Jobst Brandt), or the mechanics (Sheldon Brown).  And, not only is there a musical element to wheel-building, there is a quantum physics element as well, but more on that later.

Quando/Quanta hubs

There seems to be a bit of controversy about the quality of these hubs, but other than some sloppy machining on the spacers, everything else about them seems just fine to me.  It should only take one Portland winter for me to figure out if I have made a mistake in choosing them.  I don’t know if, because they are older, they are better or worse than newer ones.

Then, rims are needed – I chose the Sunrims CR-18 because they seemed to be priced right for my application and were going to be plenty sturdy enough for my winter/errand bike.  The cost so far: $132.

Once you’ve got the rims and the hubs, it’s time to order spokes.  Now comes the hard part.

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spocalc spreadsheet

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Freehand hub drawing and measurements

I use the spocalc spreadsheet designed by Damon Rinard.  It already has most hubs and rims built into its tables, so you may not have to take hub measurements.  Unfortunately, my hubs were not there, so I needed to take some key measurements in order to plug those numbers into the spreadsheet.  I find it easiest to make a visual drawing of the front and rear hub.  As simplistic as this may seem, it really keeps me from making mistakes at this critical juncture.  If you order the wrong length spokes, you’ll have to go and re-measure again, and sometimes you won’t know you’ve made a mistake until you are in the middle of building the wheel.  Spokes can be expensive, so mistakes can add up (Another tip:  do not pour yourself a snifter of brandy while taking hub measurements.)

You can see that the spreadsheet gives lengths for different cross patterns.  I always use a 3 cross pattern, and you can see the bias in the spreadsheet for a 3 cross pattern as well (highlighted in red).  Also, I always use 14 gauge spokes so I won’t have to stock anything but 2.0 mm nipples.

For a reality check,  I look at the output and say to myself:  are the drive side spokes shorter than the non drive side spokes for the rear hub?  Check.  Are the front spokes longer than the non-drive side rear spokes (because in this case the front hub has a smaller flange diameter)?  Check.  So far, so good.  I place my order.  That adds another $91 to the cost.  Yes, spokes ARE expensive, plus I usually order a few extras, just in case (see below).

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When the order arrives I carefully separate and label the spokes.  Then, I disassemble each packet, count them, and measure them to make sure they are really the correct length (a practice based on experience).  Then, I slowly and carefully reassemble them into their separate length packets and place them in different parts of the shop.  Do not let your spokes of different lengths congregate!  They are instigators.  If allowed to interact, all hell could break loose.  Spokes also have quantum physics characteristics.  They can change merely by being observed.  For example, once you measure a spoke, you can set it down, and when you pick it back up again, you’ll get a different measurement.  Also, spokes can be in two different places at once, and can multiply as well as disappear.  Be very alert!

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I like to work outside when building wheels – it’s kind of a relaxing experience when the weather is nice.  For resources, I follow Sheldon Brown’s wheel-building guide, and then I use Jobst Brandt’s book as a back up and technical resource.  In the photos above I have first installed the trailing spokes, with the key spoke inserted into the correct position so that the valve hole will not have crossing spokes above it, and so that the rim logo and hub logo are visible when peering down from the valve hole in a straight line.  If you read his instructions carefully, you’ll get this part right.  In fact, once you have your trailing spokes in, the rest of the spoke lacing process is a piece of cake.

I like to build the front wheel first so I can get back into the hang of it.  Since both sides of the hub flange are equal, all the spokes are of the same length.  Once that wheel is trued and dished, then I start on the rear wheel.  For spoke tension, although I do have a Tension Meter, I don’t actually tend to use it, but like to follow the musical note method (see, it IS a musical after all) of testing for proper spoke tension.  All the while I am mashing pairs of spokes together in my hands and smashing the heads against the hub.  This provides the tension relief (for the spokes, that is).

Quando/Quanta sealed cartridge hubs on 36 hole CR-18 Sunrims

Quando/Quanta sealed cartridge hubs on 36 hole CR-18 Sunrims

And there you have it.  It took me a number of hours to complete these, partly because I made an initial error on the front wheel when placing the key spoke, so had to take the wheel apart and start over.  But, the wheels look great, and I really like the way the red seals on the hubs pick up the red color on the rim logo.  Now, time for the brandy…