I’m writing because I have a problem and have not been able to find a solution, although I have seen that many people had similar problems. I have a xs-1fpa bass and the truss rod maxes out too soon to straighten the neck. I get a minimum relief of 0,50 mm. (0,02 inches at the eighth fret with the first and seventeenth frets pressed) with the truss rod maxed out. In my experience adjusting other guitars and synapse guitars (not basses), this truss rod seems to allow for fewer rounds than others, reaching its maximum sooner than expected. The truss rod is working properly on both ways and I am using extra light strings. Without strings and with the truss rod completely loosened, the neck shows more relief than other necks (which normally are completely or almost completely straight).
I have though of dismantling the truss rod nut (and the string holder) to check if it is really maxed out or if there is a problem with the threads or lubrication, I also considered adding spacers or swapping the nut if it has not many rounds. There are other aspects I have considered such as the truss rod end having moved forward or trying to straighten the neck by clamping it in order to aid the truss rod straighten the neck.
Before moving on, and as far as many people had issues with synapse truss rods, I would like to kindly ask for any guidance. Does anybody have a similar experience with this bass?
Thanks in advance!