Wheelbuilding / Wheel Building / Wheel build help

OK:

Have been trying to rebuild a rear wheel replacing the rim. Old rim wouldn't retrue - the eyelets were pulling through a bit on the ds, nds spokes kept coming undone after a ride, maybe too low tension and dry ish.

So swapped rim, using an old rim (Mavic Module E) but one that seems to be in good condition, not very worn, not pringled, no flats, eyelets all sitting solid. Went around swapping spokes over, putting oil into each nipple as I went.

Took a while to true (in a frame, not jig), but now is going out of true fairly noticeably after 30 miles or so. Retrue, same problem. As fair as I can tell the tensions were fairly even, and not extremely diff from DS/NDS. Hub is a hi-lo.

The thing I'm thinking is: new spokes needed. The old ones are Sapim Strong DS, Sapim Race NDS. Any thoughts?

The clue is in the "as far as I can tell"... How far can you actually tell? That normally happens when you build without a tension meter... not only you want the tension even, but you also want it high enough and that's not something pinging spokes with your fingers will tell you. Don't be old school and get a tension gauge, the Park one is very reasonably priced
And don't forget to de-stress the wheel while you build