Adventures in Wheelbuilding

[ReapThaWhirlwind]

I've recently started up my adventure into wheel-building. I've got two wheels completed now. Both 20" bmx wheels.

Mission Merlot 36 Spoke Radial (hoop built for straight laced spokes)

Alexrims 36 Hole 3 Cross Lacing (hoop profiled for 2 left 2 right groupings)

I've tried to gather a decent amount of knowledge from sources when it comes to the truing process. Some things don't seem to match up in my own experiences. Many suggest that a wheel should be dished with extra tension on the drive side, but I personally believe you want all the spokes to have a quality amount of tension on them. It makes the wheel stronger and more rigid. It helps to enable the wheel to stay true longer and makes it harder to knock the wheel out of true.

Another person mentioned that—what's more important than the overall trueness of the wheel—is that all the spokes on the [same side of the wheel] have equal tension. I don't find this to be very reliable information, because there is naturally a different amount of stress on the spokes for how they reach through or over the hub. This being said—it seems moreso that it would be important that all the spokes on [the same side of the flange] have equal tension. Which based on my experience seems to happen kinda naturally if you're building the wheel up very firm and tight.

Spoke length was the next big issue that I've found complications in. Many say that the spoke length can be 1mm over, thus prompting you to round up when you plug in your schematics into your spoke calculator (especially if you follow the rule of thumb for rounding). However, in my experience, I've found that rounding up (and then being 1mm over) can totally ruin your build. The spokes will be too long and protrude from the hoop, as well as have the nipples bottom out on the spoke threads before any tension is on the spoke.

Considering this, I would suggest rounding down when you do your spoke calculation. Don't use the rule of thumb for rounding, especially if you're trying to use the same size spoke for both sides, and both front and back wheels.

Anyone have any insights of their own on wheel-building and the truing process?

[Jesper]

I generally refer to Jobst Brandt's book: "The Bicycle Wheel", but build more to my own tastes and specific needs and bike usage. Building wooden wheels is a completely different beast given the unique characteristics of the wooden rim (and specific type of wood used), preconditioning before building, storage during riding season and idle season. I make my own natural skin drum heads (on wooden and metal drum frames) so I am able to apply much of that knowledge towards that type of wheel building. I do not recommend using old original wooden rims under most conditions; best left for the showroom floor.

[ReapThaWhirlwind]

Wouldn't imagine they are lighter than metal ones, but they do look fancy.

Can't wait to build my first carbon wheelset. I just saw carbon spokes on the rise now.

Generic ones posted for sale on AliExpress are $8 each (straight spoke).

Running 20/24 that comes to $300 for just the spokes in your wheels.

[jeffg]

Over the years I have built many wheels with good results. Only one wheel turned out poorly and it was due to spoke length being too long. Back in the eighties I worked in a bike shop and was handed the Brandt book on wheel building and told to read it, but found it was above my pay grade! I was given a set of rims/spokes/hubs and went about building them using instruction I found in Bicycling! magazine. (Only recently did I toss that rag into the bin as I hadn't needed it for decades.) the Bicycling! article was a dumbed down version of the Brandt book and fit my intellect more closely.

Spoke tension gauges are essential when building a high-tension wheel, but a wheel can successfully be built without a gauge as most of the wheels I have built have been done without one. I have a friend that builds wheels of all types and he uses a tensiometer as well as dial gauges for run-out. Without a doubt his wheels are perfection whereas my wheels are done well enough to be durable.

Lastly, there is nothing more relaxing than lacing up a wheel sitting about listening to music or watching a sporting event. Enjoy the pursuit of wheel buiding.!

[ReapThaWhirlwind]

Ran into an issue today lacing a high flange hub to a BMX rim.

The spokes apparently were 1mm too short and in a 4 cross pattern wouldn't reach the nipples at the end.

I've built 3 cross patterns with no problems. So it appears that 4 cross pattern demands much more precision.

Rounding up or down can be extremely subjective. I took the measurements with a 1mm error in the Internal Rim Diameter and it produced a value that would suggest rounding down would be okay. Unfortunately, this would not be the case.

[ReapThaWhirlwind]

So—I took the measurements again.

Then I took the measurements again for another wheelset I want to build at 4 cross.

When comparing the values and considering whether to round or round down, I noticed that it might possibly be the size the flange that caused the error in the rounding process. The large flange hub obstructs the spokes more when they have to stretch over them, so the direction in which you need to round in technical cases may depend on the size of the flange you have.

Not simple for a 4 cross pattern, but for a large flange hub you want to round your spoke value up.

I am going to go ahead and order the spokes for this Deore XT wheelset rounding down (instead of rounding up) so I can compare.

[ReapThaWhirlwind]

So I went and measure everything again-again. And it turns out my initial measurement wasn't rounded dramatically up, but that rounding up would be by a dramatic 0.8mm.

Also turns out I will not be able to do my Deore XT wheelset in 4 cross because it's only 32 hole.

You have to divide the number of holes by 9 to find the maximum number of cross you can do.

32 hole can only do 3 cross at max.

36 hole or greater is needed to do 4 cross.

[ReapThaWhirlwind]

Gotta definitely be careful on dishing.

I find that overdishing will give make your wheel less stiff. The spokes will come undone easier. The spokes and nipples will be more likely to break also, because of the vibration and friction. I like to give the drive side (or disc side) a slight lead, then strongly ratio the two sides, so I have good tightness on both sides.

Calculating the spoke length has been by far the most mind-wracking thing about building wheels. Off by just 1mm ends your wheel build. When you have inbetween values, rounding can be a wild swing. So I will check the next mm to both sides.

The size of the nipples you use will change how effectively you can use the spokes you have. The reason for this is because it changes where tension begins on the spokes. 12mm spokes require a spoke a mm longer than 14mm (which are the worst nipple length in my opinion); and 16mm is the best. It helps to cover cases where you would be 0.4mm short and is reverse compatible to being a little over. I believe 12mm nipples can also help cover this some. To use 14mm nipples, you need precision cut spokes or have very favorable conditions to a whole value. If you're under by like 0.3, when you go to true it up, you'll end up with tight spokes that have threads showing. Some people say it's okay, but it looks gaudy, and I've rebuilt every wheel so far where I've had this issue.

Wheelbuilding is not easy. Anyone who thinks to take it up better be prepared for way more than they bargained for.

One of the biggest noob mistakes you can make is trying to build a wheel on a single size spoke. There's such a small window of opportunity where this is actually possible. When the calculator says you need a mm longer on one side, it really means it.