I’ve previously trued other rims, replaced spokes, along with rebuilding wheels. I’ve just never done it with brand new rim. I’ve always arrived at a point where I decided “this is the best I’ll get with this old beat up rim” when I had low/high spots.
Currently I have a low spot with my new rim where the rim is joined together. I’ve tried loosening the spokes at this location. Any adjustments make lateral adjustments worse. After fixing the lateral problem I end up with the same low spot. It’s around 1mm. I’m aware of Sheldon Brown’s (https://www.sheldonbrown.com/wheelbuild.html#tensioning) advice:
A rim may be a bit irregular at the seam – usually directly opposite the valve hole – see Machined Rim Sidewalls. If the rim is welded, grinding away excess metal may have left a slight hollow. If the rim is pinned, the ends may not line up perfectly. You may need to relax your truing standards slightly at the seam, average the vertical truing for the two sides, or guide by eye on the underside of the rim.
Normally be fine with this but when I spin the rim the frame (my default trueing stand) wobbles back and forth from this low spot. I may be extra nit-picky with this rim as it’s my first all new build and it’s my freewheel setup. I’m already anticipating extra difficulties with the freewheel hub. Hence my desire to get it as close to true as I can that way all blame ends up on me, not on the uni.
Video of the best I’ve been able to get it so far.
Looking for any suggestions to remedy this out of round low spot.
I agree with emile, I think you did a good job and that’s about where I’ve left my wheels too. Pretty much all rims I’ve laced had this exact thing, with a slight wobble at the seam. Most tires are less consistent than that, so I call that good enough. If it was for a roadbike with thin high pressure tires, maybe more attention is needed, but with a 2.5" Muni tire at moderate pressure, that will not be noticable at all.
My philosophy is also that I’m willing to trade a slightly off true wheel for more even spoke tension, especially when trying to pull out a very localized bend in the rim.
Also agree with “pre stressing” the wheel, or alternatively, retensioning and re truing it after your first few rides. That in itself is a good reason to not chase perfection too hard now, you’ll probably have to do it a second time anyway. (After doing that once or twice, your wheel should normally be settled.)
My method for pre-loading a first centered wheel, as a tip I got from a bike mechanic:
place the wheel sideways on the ground, supportet on 3 places, step on the spokes and walk around, then repeat on the other side. First time I tried, I feared I would ruin everything, but that never happened.
So, I usually pile three blocks of books on the ground, enough to lift the axle off, place the rim on the books, and then take a walk on the spokes, two times each side, then back to truing again. My weight is 90 kg, never broke anything this way, I have been working with ok-quality mountainbike material. Since uni-rims are stronger, I would expect no problems.
No guarantee for anything, just my two cent and experience.
I agree with the others that you seem to have done a good job, and it will work - new rims are never perfect, and “perfect” spoking can’t fix everything.
Sometimes an “out of round” condition CAN be fixed by differential spoke tensioning, followed by some riding, and then when the rim gets a new “shape memory”, it MUST be trued again (so the spoke tension can be made more even). BUT this only works if you have a large/slow area of imperfection, which can be addressed by adjusting quite a large number of spokes. If there is a little “bump” (like yours) it CAN’T be fixed by spoke tension adjustment - there are not enough spokes “active” in that small part of the rim to adjust.
Luckily your rim “bump” at the rim join is an inward bump, so a fairly solid tire will just “bridge it” and the ride will be perfectly fine. And of course, tires are imperfectly round anyway!
The imperfection at the join is probably due to whatever rim rolling machine the manufacturers use - maybe some robotic or human guided thing which grabs the ends of a newly rolled rim, bends those ends to align them, pushes them together and attempts to correct any shape imperfection introduced by that process.
Having stupidly reversed over my unicycle wheel with my car once, I can attest that the pinned rim join is a weak part!
Regarding stress relief (e.g. by bashing or pushing or spoke walking), I think there is a nicer way to do it, as recommended in Park Tool videos - just put on some gloves and grab little groups of spokes near the crossing point, and firmly squeeze (going round the wheel a couple of times). I reckon bike mechanics just want to get the job done as quickly as possible and also, they do it aggressively to make it absolutely certain that the customer won’t complain about spoke creaking in the next couple of weeks. The squeeze method has worked perfectly for me, and anyway, if you are doing it yourself then it is no big deal to check and adjust tension and trueness after a few days of riding.