One bit of my rim (less than the distance between 2 spokes) is 0.2--0.3mm wider than the rest. It causes a pulse of increased braking once per revolution, which is annoying. As the rim isn't worn and there are no signs of thinning, I'm inclined not to be too concerned, but I'd like a 2nd opinion - and even better if I could make it less annoying.
This is a fairly lightly used aluminium rim - I bought it new to build up a dynamo wheel for commuting a couple of years ago. That bike died, but I've put the wheel on another bike. I noticed this issue on the previous bike, but didn't solve it (I assumed it was the join).
The rim has a spot that's a tiny bit wider than the rest. I can feel the increase in the braking (V-brakes) at typical everyday braking forces. Having assumed it was the join, or a rough patch, I looked a bit more closely, cleaned and felt all round the brake track. No issues detectable by sight or touch.
Walking the bike with very light pressure on the brake allowed me to find the spot where it catches and get the Vernier calipers out. It's neither near the join or the valve hole. The wear indicator groove in the brake track is as good as new, and the brake tracks aren't shiny enough to see if a reflection is distorted on one side or the other.
Measurements with no tyre showed variation on a scale of 0.1-0.2mm inside and 0.1mm outside except this spot that was 0.3mm above the minimum, with no correlation inside to outside. In practice there was also a measuring error on a similar 0.1mm scale even taking the lowest of 3 measurements in almost the same spot (probably due to minor scratches/dings, or just to not squaring up the calipers perfectly). Without the weight of the tyre+tube, it was harder to locate the problem region by spinning the wheel and taking up the slack in the brakes, but I didn't have time to fight the tyre on, off, and on again over lunch and it needs to be rideable this afternoon. It does seem to just be variation in the extrusion.
Unfortunately the bike is now the one that never goes home, so I'm limited in what I can do to it.