Hard at work building wheels again today.
It’s the most fun I could ask for.
Today’s job is a wheel rebuild, replacing the rims because they have reached the end of their service life.
"What do you mean, a rim's service life?"
I imagine that’s what many of you are thinking.
So today, let’s talk about just that.
The rim is one of the components that make up a wheel.
It’s surprisingly little-known, but it is very much a consumable part.
The more you ride and the more you use your brakes, the more it wears down.
Let’s take a look at how it reaches the end of its life.
First, here is a healthy state.
There is no gap in the area circled, and the braking surface of the rim is flat.
Now, let’s look at a rim that has reached the end of its life.
There are several large gaps on the braking surface, and if you touch it, it feels bumpy.
This is because the rim surface has been worn down by friction from the brakes, creating ridges. In some of the deeper spots, it has worn down by over 1mm.
Once it gets to this point, braking performance drops, and if you keep riding, the sidewall will thin out, eventually leading to a major incident where the rim splits.
It would be one thing if it split while standing still, but if it happens while riding, it could lead to a serious accident, so if you start to feel ridges, it’s time to call it done and replace it.
"But how do I know when it's reached the end of its life?"
This varies by rim, but as shown in the photo below, some have wear indicators similar to tire wear bars.
Whether it’s a line or a dot, if there is some kind of mark, you should replace it once that mark is no longer visible.
If there are no marks, you should replace it if you feel an uneven or wavy sensation when running your finger over the surface.
So, first, take a check of your own bike, and if you think something looks suspicious, don’t hesitate to consult with us at any time!