Can you convert threadless to threaded headset?

[nirakaro]

I’m looking at a second-hand bike on eBay – I only want the frame, to move all the components across from an existing, same model but older, bike. This will involve scrapping the existing threadless headset, and refitting my present threaded one. Will the head tube dimensions be compatible?

[531colin]

I think so, if both are inch and eighth straight ( not tapered) steerer and old fashioned external cups on the head tube.
Of course they might have changed head tube length
E&OE!

[gregoryoftours]

What is the bike you have and what is the bike you're thinking of getting? Is your current bike 1 1/8" steerer fork or 1"? And do you know if the eBay bike is 1" or 1 1/8"? Are the frames the same size? Photos or links to both would be helpful, especially head tube. Of course you will have to use your current fork with the new frame if you want to keep your current headset.

[rjb]

Most things are possible to mix and match. The solution depends upon getting around the issues one finds. I've fitted 1" forks to 1,1/8 frames. The 1" crown race supported a 1,1/8 headset without issue. The only problem was working around the upper race. A tapered adapter may be required. I recall Brucey used external cups to squeeze a 1,1/8 fork in a 1" head tube frame. If you find your new frame has a steel fork column then your quill stem may still fit and you can keep the thread less headset.

[531colin]

.. If you find your new frame has a steel fork column then your quill stem may still fit and you can keep the thread less headset.

Minor ingenuity required to adjust the preload?

[rjb]

.. If you find your new frame has a steel fork column then your quill stem may still fit and you can keep the thread less headset.

Minor ingenuity required to adjust the preload?

It took a while for anyone to notice.

[Brucey]

I’m looking at a second-hand bike on eBay – I only want the frame, to move all the components across from an existing, same model but older, bike. This will involve scrapping the existing threadless headset, and refitting my present threaded one. Will the head tube dimensions be compatible?

if the extant frame and the new one have (respectively) 1-1/8" threaded and conventional 1-1/8" threadless (ie. with push-in cups) then my understanding is yes, the cup diameters (where they enter the frame) should be the same.

[rogerzilla]

1" head tube frames can be converted to threadless too, and vics-versa, as the cup insertion sizes are the same as threaded. Threadless headsets in that size were never common, but are available from, e.g. Tange. 1" threadless forks are very hard to find new.

1" threadless is a bit like Betamax, though, and the market has seemingly decided that 1" = threaded and 1 1/8" = threadless.

[Nearholmer]

I know it’s not relevant, but I keep asking “why?”.

So: why?

[rogerzilla]

My guess is that the OP either has a nice threaded fork, prefers quill stems, or is trying to get away from the evolutionary dead end of 1" threadless. I wouldn't convert 1 1/8" threadless to threaded, as 1 1/8" threaded is another evolutionary dead end, but I can see the point of doing it for 1", where threads and quills have turned out to be the preferred option.

[Brucey]

I have used a set of adaptor rings, which allow fitment of the smaller 1" headset (with 30.2mm cups) to a frame designed for 1-1/8" cups (eg. with 40.0mm openings). I would expect to be able to make such things, easily, from wood if necessary, bonded in place using epoxy resin .

[rjb]

I found a 1" fork with its crown race located nicely in the tapered bottom of a 1, 1/8 headset meaning you only need a reducer ring at the top.

[Brucey]

I found a 1" fork with its crown race located nicely in the tapered bottom of a 1, 1/8 headset meaning you only need a reducer ring at the top.

as per my 'rubbodraulics' post you can easily make a rubber crown race (eg using old inner tube) provided it has a steel capping. The capping can be cut from sheet steel. Such races are, of course, easily removed and refitted. Should the steel piece not quite cover all the rubber, no worries; it will just improve shock absorption, but you might need a tad more preload.

[nirakaro]

I know it’s not relevant, but I keep asking “why?”.

So: why?

I want a smaller frame. I like quill stems.

[hercule]

You can also get headset spacer tension adjusters that will allow you to use a quill stem with a threadless headset, but I suspect they are all 1 1/8l” and all quills are 1”