Recently removed the expander plug from my fork steerer as I needed it for another bike. I didn’t have to loosen the stem so the headset is still nice and tight.

Is it safe to ride without replacing the plug. Assume so but don’t want to die. Its an alu steerer on a cx bike if that matters any?

Yes. It’s the stem that holds everything in place.

ta

Yep. Only issue is if you needed to adjust it while out but can’t imagine that is likely*, and even if you did you can bodge it by pushing on the top of the stem to load the bearings.

* I have crashed hard enough to twist the bars and have to straighten them before

You will die.

(but this is unlikely to be anything to do with your death which will, hopefully, be many years from now)

as they say once it has preloaded the stem you could take it off anyway so fine to do this

the only issue i can see with this is that then your stem top cap, and any spacers above the stem will have nothing to hold them on. leaving an open tube with potentially sharp edges waiting to be landed on.

if there is a way of securing the top cap then you’ll be fine

The Star fangled nut/expander is a pre-load device. The bolts on the stem hold everything together,you would be very unlucky to have it twist off completely unless bolts were not tightened. You could have your butler tap in an old champagne cork if worried about the open tube……..?

You’ll get away with it short term but, despite the theory, it will work it’s way loose over time. It shouldn’t, but it will. The cookie cutter effect on the top of the steerer could be an issue in a crash.

As long as it’s not a carbon steerer. I tried it once on a carbon road bike and the stem would not stay straight at all.

You’ll get away with it short term but, despite the theory, it will work it’s way loose over time. It shouldn’t, but it will.

This, it happens even faster on BMXs, where the headset only stays tight if the steerer protrudes a good way through the stem and you run a top cap, tightened down proper tight AFTER you have clamped the stem on. I do both of the above on MTBs too and the headset stays rattle free indefinitely.