From Rookie’s Keyboard,
Hello, today I am going to “red pill” you about the bleak reality of single-wall rims.
In short, single-wall rims are awful and unless they are your only option for whatever reason, it’s best to avoid them like a supermarket selling food produced in 2019.
Single-wall rims offer two lose-lose situations, namely:
- Option 1: Heavy and strong
- Option 2: Light and weak
For a single-wall rim to be as strong as its double-wall equivalent, we have to greatly reinforce its single layer.
The extra material adds thickness/strength but also a lot of weight. That’s an issue because more rotational mass on a bicycle creates greater pedaling resistance and hurts your average speed.
Why do it when you can get a double-wall rim that’s lighter and stronger?
Two situations come to mind:
- No other options
- No access to a quality double-wall rim
But the downsides of single-wall rims do not end here.
The most annoying problem is the incredibly high risk of getting a flat tire caused by spokes that are too long.
Even if a little bit of a spoke (like 0.5mm) protrudes outside of the nipple, then there’s a very high chance that the spoke will pierce the rim tape and then the inner tube.
This phenomenon is known as an “inside job flat” (I coined that term) and could be quite annoying, especially when you encounter it for the first time and have no idea what to look for.
It happened to me at the beginning of my cycling journey when I was on my way to work. I changed the inner tube without finding anything sharp in it. Then, 15-20 minutes, later it went flat again. It took me two more tries to finally realize that a long spoke was behind the problem.
I must specify that you can experience the same issue with double-wall rims (as in my case), but the tolerance is greater because the second wall increases the distance between the spokes and the rim tape.
And you can get away with spokes that are slightly longer than necessary. (I’ve done that routinely.)
Other issues that single-wall rims create are:
- Fewer options due to the low demand
- A less resilient wheel when all parameters (e.g., materials, quality) are equal.
A single-wall rim is a lot more likely to get out of true (lose its roundness) than a double-wall equivalent. If you don’t like the process of truing a wheel (it’s not complicated but it takes some practice), this could be another source of annoyance.
I’m fine with truing a wheel occasionally. I don’t even have a stand. I do it the ghetto way – the wheel is either in the frame or fork and I use zip-ties to measure the misalignment. It works. I’ve even built wheels from scratch using this method.
But if you don’t want to bother with the process (very likely if you’re a rookie) just get a strong rim from the get-go. It’s going to survive a lot of “adventures” before it needs re-truing.
Let’s get a bit technical.
Some people may be wondering why double-wall rims are both lighter and stronger.
It’s because most of a hollow cylinder’s strength comes from the walls. In this case, of course, we don’t have a “standard” cylinder (that would be frame tubing), but that same principle applies as the space between the two walls is hollow.
If we have a solid rod and a hollow cylinder made of the same material and in the same amount, then the hollow cylinder will be more resistant to force because most of the stress is on the external structure (wall).
The material used for the rod is evenly distributed which means that the walls of the rod do not have as much reinforcement as those of the hollow cylinder. The result? The rod is easier to bend, and the only way to improve its strength is to make it thicker at the expense of extra weight.
Tables Work Best
Below I have prepared tables that would serve as a nice summary:
Single-wall Rims
| Pros | Cons |
| Cheaper | Weaker (or heavy) |
| Easier access to the spoke nipples | Heavy (or weak) |
| You can’t lose a nipple in the rim cavity since there is no cavity. | Low tolerance for spokes of improper length (internal flats can occur easily) |
| No room for error when it comes to rim tape | |
| More likely to lose their roundness and requires re-truing | |
| Not as stiff (when the same amount of material is used) |
Double-wall Rims
| Pros | Cons |
| Strong and lighter when all qualities are the same | More expensive (when the quality and the materials are the same as those of single wall rims) |
| Less likely to get out of true | Harder access to the spoke nipples |
| More tolerant when it comes to spoke length (lower chances of internal flats) | You can lose a nipple in the rim cavity. It’s annoying to get it out but possible. You can’t use magnets btw as the nipples are made of brass or aluminum. Rotate the rim as many times as needed to get the nipple out of the valve hole. In all cases, don’t let the nipple in the cavity as it will rattle and annoy you. And if you have OCD…it will be a nightmare. |
| More tolerant of rim tape issues (e.g., the rim tape moving a bit out of position) | |
| Better for aggressive riding | |
| Stiffer (=reduced power loss) |
TL: DR;
Bros, it’s simple. If you’ve bought a bike with single-wall rims just ride them until they’re toast. If you are currently looking for a set of new wheels, just do yourself a favor and get a decent set of double-wall warriors. They will be stronger, potentially lighter, and will require no maintenance for a long time…unless, of course, you get unlucky and hit a wall on your first day.
But let’s keep it positive, fellas. It’s Friday.
P.S. If you don’t have the money for a double-wall rim, just skip a few packs of cigarettes and get a generic one.
Until next time
Yours Truly
– rookie
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