How To: building wheels
Building up wheels on a project bike isn’t the first task that most folks attempt. Although the basics of the procedures are straightforward, the task of truing a wheel can seem daunting. Nevertheless, in my quest to do all the work on my bike that I possibly could, I dove into the build of the wheels.
The hubs are c1913 units from the British Hub Company. Even at this early date, motorcycle manufacturers had already begun buying in many components from trade suppliers, as opposed to casting, machining and plating parts themselves. Carbs are an obvious choice to buy instead of make (barring Rudge, BSA and Triumph, who made their own). Hubs, frame lugs, flywheels, Bowden levers, tires, spokes, gearboxes, clutches, cables, seats, magnetos, spark plugs, belts, and probably many other things were bought in, then assembled into a marketable motorcycles. Some folks might slight Brough for buying components, but all the makers did it to some extent. Anyway…
Here is the front fork, with the axle, wheel bearings, spacers and nuts. The hub isn’t shown. All this stuff is new, made on the lathe from chrome moly steel, and purchased modern sealed bearings. There wasn’t much point in making up a new set of cup and cone bearings to replace the worn out originals. But if you use modern bearings, make sure that the axle or a center spacer is in place to prevent the bearing inners from being forced towards each other. Rapid bearing failure will result. And don’t make an axle from mild steel. It might work, but chro-mo is much stronger for just pennies more.
The outer spacers were designed to emulate the look of the old cup and cone setup. They are not 100% perfect visual copies, but they are close enough for me. I don’t have a photo of them after nickel plating, but they look sharp.
Spokes. There are a few suppliers for skinny spokes. But I don’t use the company in Southern California. I found that their smallest spokes are still way too big for 19teens bikes. You could drill out the holes in the hub and in the rims to fit, but it wouldn’t look right. In the UK, spokes can be bought in the original gage sizes from Central Wheel Company or the Brickwood Wheel Co. I used Brickwood, but the prices and quality seem to be the same. The rear wheel is a cross 4 pattern of 10g, and the front is cross 3 of 12g. 11 gauge isn’t made anymore. Stainless spokes work well, and don’t rust like the old ones. But be sure to use brass nipples that are nickel plated. Using stainless nipples and spokes (or stainless nuts and screws) together is a no-no. The stainless will tend to gall or weld together. Using dis-similar metals prevents this.
This tool is used to roll the threads onto the spokes. Rolling threads is stronger than cutting them. The three little wheels have edges that are negative shapes of threads. When the spoke is put into the rolls and the rolls are spun, they form thread teeth into the spoke. It is clever, but you must use some oil and have precisely the correct rolls for the spoke diameter, or it will not work.
A preliminary test fit of the spokes onto the front wheel. using 6-8 spokes, you can check to see if the spoke length is correct. It is fun and challenging, as it is easy to put them in the wrong place and get the wheel very wobbly!
The rear wheel spokes also need to mount the pulley for the V belt drive. Some bikes used an additional set of short spokes from the rim to the pulley, but mine screwed the pulley directly to the main spokes. I made up these little spacers and clamps, cross drilled to accept the spoke. That meant that they had to be slipped onto the spokes before the spokes were laced into the wheel.
Getting ready to lace the wheel what I thought was the last time. The computer has photos of the old wheels for a reference. This is invaluable. Get photos of assembled wheels if you can, it makes it so much easier to lay out the spokes. Use one bottle of engineer’s lubricant. I chose Racer 5 IPA for this build. Using two or more bottles may affect your build quality.
Following Radco’s advice, I assembled all the spokes to the hub, then slipped each group into the rim. Starting with the top set (outside spokes on top hub flange). The inside spokes, then lower flange, etc. For a cross 4 pattern, this is the only way to lace them. For a cross two or three, you might be able to build the wheel with one spoke at a time. Start by slipping all the inner spokes into both hub flanges. Then put those into the rim one at a time. Then slip in each outer spoke into the hub and then into the wheel. But for cross 3, you’ll find that the existing spokes get in the way when you try to put in the later spokes. You can remove one spoke to insert one, then replace that removed spoke. One step forward and one step back… But when you have a cross 4 pattern, you’ll have to remove three spokes for every one that you install. That doesn’t work. So stick with the plan to assemble them all on the hub, then carefully introduce that assembly into the rim. A second set of hands will help to hold the spokes, or use painter’s tape to keep them from scratching the painted rim. I put three small boxes on the table to lift the rim up to be centered on the hub height. That helped a lot. The first set of spokes goes in easily. At the rim it is spoke, hole hole hole spoke. The second group alternates to be spoke hole spoke hole. But the third group can be hard to start. You must double check your photo to see where the spokes from the lower flange are relative to the spokes from the top flange. It you get it right, the spokes will swing out and stop just about at the rim distance for their hole. If the spoke seems way too short or too long to reach the target hole, then stop and double and triple check your photos. The fourth group of spokes (outside, bottom flange) are easy, as they just drop into the remaining holes in the rim.
One more tip, be sure to lubricate the nipples. The spoke maker will probably supply a little bottle. I don’t know what it is, maybe an organic oil of some kind. But it flows better if you heat it up in a bowl of water. It acts to lube the threads and to be an anti-sieze so they’ll come apart later.
Ouch. The rear hub flange broke while I was tightening the spokes and truing the wheel. It might have been hydrogen embrittlement. I did cook the hubs at 350F for 4 hours after nickle plating, per the recommendation of the plating shop. But there might have been a crack during the last 100 years. After a quick search for a replacement hub didn’t produce any leads, I decided to repair the hub. There wasn’t much time to finish the bike before it had to be ready for the Pioneer Run, so the repair was chosen. I’ll continue to look for a suitable hub and replace it later when time permits.
I made a centering spacer to fit inside the hub, and chucked it up in the lathe. Turning off the flange, I left a small shoulder to register the new flange against, and to resist the spoke forces that pull the flange inwards.
The flange was made up pretty quickly from some round bar stock on the lathe. Setting it up for the hole drilling took longer than any other aspect of the project. Here I’m drilling 20 holes, each is 18 degrees from the previous hole. The cheat sheet on the left counts out 360 degrees in 18 deg increments.
Before I pressed the new flange onto the hub, I made sure that the holes were NOT LINED UP with the holes on the opposite flange. Each hole needs to be spaced at one half of the pitch of the opposite. Otherwise the spokes would need to be different lengths.
The flange was pressed on, then cut to final dimensions in the lathe. After polishing the flange, I didn’t have time to nickle plate it. So I sprayed it with a rattle can of clear coat to prevent rust. We’ll see how it lasts. Once the spokes, freewheel, chain and belt pulley were installed onto the wheel, the new flange is very hard to spot.
Lacing the wheel. Blue tape holds each of the pulley mounts so they don’t rattle around too much.
The rear wheel, assembled for a test. The stand is used to true the wheel. I borrowed this one from a friend, but truing can be done in the motorcycle frame very easily.
To true the front wheel, I placed a bit of painter’s tape across the fork tubes, then measured and marked some lines showing the distance from the center of the forks. After roughly truing the wheel, I turned the tape over and made a final set of marks to finish the truing to. This way the wheel is centered in the forks and in the bike. Truing in a stand is good too, but now I know that if the forks or frame or something is off, the wheel still fits. For a front wheel with no brake, it is also possible to install it ‘backwards’ and see that it is still centered.
Truing the wheel is fun the first time you do it, but it is also frustrating. I’m not a wheelwright, so I won’t give much advice. But start by setting the radial runout to be even. Then work on the side-to-side alignment. Don’t be afraid to loosen some spokes and let the rim move, instead of only tightening and tightening. And do a good final check on all the spokes that they are somewhat evenly tight. A Google search will probably give better advice, maybe from bicycle builders…A