Threaded steerer, your thoughts please

[BalkanExpress]

I have found the period correct 1” threaded fork for my Carrera Podium. The issue is it has come off the bike of someone very very tall. My bike has a 16cm head tube and on the “new” fork had the steerer tube is 23cm long and threaded from 19cm upwards.

I think my options are:

Cut it down to 19c, have a new thread cut and use a short stack headset (Shimano Deore is 33mm)

Cut to around 20cm and extend the remaining thread, I understand this is possible but tricky

Cut it down and use a threadless adaptor and an ahead stem (I have a period correct one available)

What advice would you have? do I have all the options, or have I missed something?

Many thanks

 

[si_c]

I think it might be worth checking with a local bike shop - they very may well have a steerer tube threading tool, especially if they've been in business for a while. It should be a relatively easy task for them to extend the threads down the tube to the height you are looking for and then cut it to length.

 

[IanSmithCSE]

Good evening,

I don't know if this is relevant but Reynolds 531 steerers were butted, so maybe yours is as well. I'm not familiar enough with the model but Columbus Thron comes up from a quick search and that is also a quality tubing.

Unlike the frame tubes 531 steerers are butted the other way around, they are thinner at the end where the stem goes in. So if you cut off too much of this thinned down end the bottom of the stem may hit the thicker internal part of the steerer whilst still being too high for the desired riding position.

However this will be obvious when you try and position the stem so it won't be dangerous and you can still use your third option and go modern!

If you find that you have to bang the stem to get it down to the desired height you may want to take it out again and see if the expander end of the stem has been squashed.

Bye

Ian

 

[rogerzilla]

I have a fork die, and have chased threads, extended them and cut new ones from scratch. Are you really in Brussels, though?

 

[Specialeyes]

I have a fork die, and have chased threads, extended them and cut new ones from scratch. Are you really in Brussels, though?

Definitely in Brussels

In view of the potential that the steerer is butted it might be worth finding a piece of 1" something-or-other and shoving it in there to see if it does move freely to the extent that a 1" stem would on the cut-down tube. Whether 1" pipe is available in Brussels is another question. If it's not I'll post you some. I'm also assuming you can't really tell just by looking as it'll just look like the inside of a tube

Then I'd be inclined to go with the option to cut the steerer and extend the thread or rather, find someone who could do it for me! (In a similar fashion to how I overcame the reverse problem and had a steerer tube extended last year - a fine theory, just need to find someone who can do it in practice!) But I'm sad like that! Others would stick an a-head stem on it and have done with it. Depends on the purpose of the bike, really and how much it warrants - e.g. if it were a Pegoretti, then definitely a quill stem.

Keep us posted! Definitely need some projects to follow through the rest of the winter 👍

 

[rogerzilla]

You'd need 22.2mm pipe or smaller to shove down there, not 1". 1" is the OD.

 

[mickle]

One inch fork steerer thread cutting tools are not all made equal. The ones that you'll find in a frame building workshop are are designed for cutting a thread into a blank steerer tube. The sort that you'll commonly find in a bike shop are designed only to chase and clean a deformed thread.

 

[mickle]

If it was mine I'd give up on the threaded headset, install a threadless unit and stem and chop off the excess. I've bodged this on one of my bikes with no ill effects. My inch and eighth stem clamps entirely to the threaded section via an aluminium shim. The stem is thusly protected from being scored by the steerer threads. The soft shim grips the steerer happily. This is not an endorsement of such behaviour.

 

[rogerzilla]

One inch fork steerer thread cutting tools are not all made equal. The ones that you'll find in a frame building workshop are are designed for cutting a thread into a blank steerer tube. The sort that you'll commonly find in a bike shop are designed only to chase and clean a deformed thread.

Mine's good for new threads. I converted a long Raleigh fork from a big frame to ISO by cutting off the old threads and cutting new 24tpi ones. It was still good for a frame up to 21".

 

[BalkanExpress]

Many thanks to you all.

The fork came off a Columbus Brain framed Carrera bike so it may be Brain , possible SL or indeed Thron. I'll see about ramming, err gently running something down it to check on butting.

My last experience of having threads cut was about 18months ago at "peak get bikes back on the road" post initial lock down and it was a real pain finding someone will workshop time and spece. Should be easier now.

I confess to being tempted by the treadless route as the current carbon fork is threadless. Bike is a Carrera EL-Max with the blue on white team paintwork. The replacement fork has the falcon in red on the fork crown and it will be a red 3ttt mutant ahead stem to tie in with the jersey

@Specialeyes there's no shortage of projects this winter, although this isn't pre-meditated enough to count as a project, I saw the frame and fork going dirt cheap, (frame is HUGE and errr rusted ) so I grabbed it.