Originally Posted by
squirtdad
Another possibility is that the tire pressure is too high, causing flexing and loosening of spokes. I got this information from a well regarded shop that is building a wheelset for me (I am building a different one myself.....got to get good at it) and they noted that going from a 28mm tires (gp5000) (run and 95 back, 90 front and i am 240) i should drop about 8 pounds pressure and going to a wider rim I should drip another 8 lbs, otherwise there is flexing and spokes loosen. I was multi tasking and so did not get the mechanics down pat, but this could be a consideration
That's a good point, and many lightweight tubeless rims will also drop spoke tension just with a tire mounted. So perhaps the wheels felt good and tight on the stand, but dropped enough tension with the tires on and inflated that the nipples were free to shake loose.
Some professional wheelbuilders will install a tire and pump it up for their final truing, to check if the wheel goes out of true or particular spokes get too slack. If it's the type of setup to drop a lot of tension, the temptation is to really crank up the spoke tension, but you need a good way to ensure that you're not exceeding the maximum tension rating.