Is there any way to hide all the dials in a figure part, without having to hide them all seperately?

Usually I just collapse the tree root node they live in (typically called Morph).

I meant in a cr2, so that the figure loads in without the dials appearing but the figure part can still be selected.

Yes, if you collapse the nodes and then save the CR2, the collapsed state is saved into the CR2 and you don't need to do it again.  Of course if you just want to get rid of the dials entirely and the morph targets that the dials drive, which is not only convenient but easier on memory usage, you can look into svdl's spawncharacter.py script (DAZ figures only I believe):
http://www.renderosity.com/mod/freestuff/index.php?username=svdl

This goes further than just hiding the dials, it consolidates all morph targets you've used into a single morph target and writes that to a new INJ/REM pose set; you can then get rid of all other morph targets and only load that one, and then save the result back to figures library as a very efficient CR2.  You may of course want to keep some morph targets separate e.g. expressions.

It is not for morphs, it is for dials like scale and x trans and I want it to work in p4 and p5 as well.

You can manually just edit the CR2 and change hidden to 1 instead of 0 for each dial on each bodypart, but that's probably too tedious for you.  I'm sure there are some CR2 editing tools out there (google).  Alternatively you can group them in a tree node and collapse the nodes you don't care about, and save that as I suggested earlier ^_^

I dont think collapsing the nodes will work, poser 4 doesnt use them.

Add

hidden 1

to each dial that you want not to appear.

Some people prefer to be able to access all the dials (no matter how useful that may or may not be), so providing an unhide pose rounds things off nicely.