Originally Posted by
dabac
I regularly rig up cradles and c-clamps and pull out flat spots. It will usually work out fine.
That might put a stop to any shaping attempts.
Straight across from the valve hole is where you’ll usually find the seam in the rim.
If that one isn’t round(enough) from the start, it’s really difficult to fix later.
And if it’s a pinned seam, it’s likely to come apart if you try to get creative with the shaping.
...this, and I also have one of these:
But to start with a box section alloy rim is a lot more difficult to reshape (the advantage being it's harder to deform in the first place.) And the seam on the rim is, indeed, gonna be about where you're doing your reshaping.
Were I you, I'd probably first try loosening the spokes along the arc you want to move outward (the flat spot) in a manner that is even on both sides (same number of turns). Start with maybe a turn and a half or two turns.
^^^the flat spot is centered at 6 on the clock^^^
Then tension the spokes tighter at 4 and 8 (again, evenly on both sides, so the rim stays centered.) that will move it outward some, usually in a nice curve. But if you want to detension the whole section and rig some sort of puller or cradle, it needs to work like the commercial tool pictured for success.