Removing the top cap from a no name Aheadset

My girlfriend bought a bike a few years back, finally found the time to strip it / rebuild it but I’m having a few problems getting the top cap off to remove the forks. The bolt just keeps turning, seemingly so far forever.It’s not the first headset I’ve stripped but it seems to have a bolt that is half an mile long at this point! Is it possible the star nut is actually mioving in the steerer tube or for the threads to have stipped?

yes it is

can you get a screwdriver blade under the topcap to prise it up?

you could try drifting the SFN out from underneath with a suitable drift and mallet…

stoner think about it – how will you be able to do that?

Your best bet is to cut through the top cap and jettison it. then knock the sfn down the tube, put in a new one and get a new top cap

how will you be able to do that?

without a shandydrinkers approach to drifting and mallet work.

If its borked, there’s nothing wrong with smashing it out from the underside.

“stoner think about it – how will you be able to do that? “

by putting a long drift up the steerer tube at the base of the crown and hitting it? That is assuming there is a hole at the base of the steerer tube

think about the shap though of the star nut – designed not to go up the tube

and I cant think of any that dont have a hole off the top of my head….

pikes off the top of my head

Maybe it has one of those tensioner devices, where there is a threaded plate below the fork crown that the top bolt screws into? could be this spinning instead. there is no star nut fitted in the steerer tube. mainly used on downhill bikes though. worth a quick check!

hence my reference to smash the bollox out of it so that the splines collapse.

as for cutting the top cap you will almost certainly mark the top of the stem unles you have a spacer above the stem and under the top cap.

if the cap can lift enough then cutting horizontally through the top cap bolt is by far the best solution.

OK, this is a very long shot but assuming you don’t know the history of the bike, I don’t suppose that it has a quill to ahead adaptor or steerer extender fitted (it would look identical to a generic aheadset top cap but the top cap bolt actually screws into the larger steerer wedge bolt. If this is the case, once the bolt is undone, a quick knock with a wooden mallet would be enough to loosen everything so that the stem and adaptor lift straight out – just a thought.

it seems to have a bolt that is half an mile long at this point!

Do you mean that the bolt is rising out from the top cap but seems long (ie maybe it IS long – carry on unscrewing until it’s out) or that it’s turning and NOT rising at all (in which case either the SFN/whatever device is likely spinning, or the thread is stripped)

I’m guessing the latter.
try loosening the stem bolts and “lift” the stem and top cap. This might put enough tension in the system for the SFN to “hold” and the bolt to undo while you continue to pull up on the stem. (if the bolt/SFN is stripped it should all just lift out anyway)

if the bolt is exposed could you hack-saw the bolt,
releasing the top cap,
then you could knock the sfn through,

if its not exposed then drill the top of the bolt,
again releasing topcap and
knock through??????

Just smash the whole lot up repeatedly, with a big hammer, then propperly lose it, and sling the bike through the window, then run outside, and smash the bike on the ground repeatedly, in front of all the neighbours, while swearing profusely all the time.

Then collapse, sobbing, at the realisation of what you’ve just done…

Thanks for all the suggestions! Tried cutting it off, got nowhere, ended up ruing a perfectly good screwdriver by using it as a drift and tapping it out from the bottom. Oh, and swearing a lot 😳