Hi

I have bought a new headset for the tandem – deep insertion as I previously have slightly ovalised the headtube with a shallow headset.

The problem is that the reamed part of the headtube is only 15 mm deep and the headset is 22mm deep.

Do I get the headset turned down or ream the headtube out deeper? I am concerned with removing to much metal from the headtube – it needs to be reamed out 2-3 mm wider and the reamed out portion is already below where is is welded onto the rest of the frame. This would leave the wall thickness 2.2mm after reaming – its 4mm where it is not reamed.

So

Turn down the headset cups to shorten them or ream out the frame?

I wouldn't ream the HT (not sure where you'd get a reamer to do the job anyway. My advice:

(Oh not for the frame!)

Know anyone with a metal lathe? Would be a much neater way to do it.

Neatness won't matter once fitted.

Is it not a stock tool for an LBS headtube reaming? I have some engineering ones that would do the job anyway. Its quite a bit of metal that needs removing tho which sort of scares me

I can get the cups turned down on a lathe easily and cheaply

What about a very thin headset spacer to go between the frame and the headset, just to take up the space?

That way you don't cut the frame or the headset?

I'd turn down the cups rather than ream the frame, easier to do and far less risk of it 'going bad' ….

TandemJeremy – Member
Is it not a stock tool for an LBS headtube reaming?

Never seen one in a lbs, never needed on either. Only seen one shop with seat tube reamers!

crikey – Member
What about a very thin headset spacer to go between the frame and the headset, just to take up the space?

And increase the leverage on the headtube?

It is an uber-expensive tool, hence why most bike shops will not have them.
CRC link

Call around a few, as you might find one in your area.

I'd get the last 7mm of the headset cups turned down to the same diamiter as the unreamed part of the headtube.
Pointless sawing the headset cups down. You may aswell put a shorter headset in than do that.

Cheers chaps – Hopefully a 15 mm insertion ( Oh er missus) should be plenty anyway – the last headset was 12mm on the bottom cup and 9 on the top.

Personnaly I'd buy a headset that fits rather than try to bodge one that doesn't

Do you know any cartridge bearing headsets with 12 – 15 mm insertion that are not stupidly expensive?

Turning it down will be fine. It will still have more insertion than the headset that came out

That's an interesting question, no I don't tbh, and a quick scout on CRC the insertion depth isn't often quoted, just stack height?

Maybe http://www.chainreactioncycles.com/Models.aspx?ModelID=24987 if the 'flange' is the bit that is inserted?!

FSA?

You can download the guide to all their headsets – clear, dimensioned technical drawings for all their headsets.

Ta HH – its an fsa pig that is coming out of the frame.

Thanks chaps

Try hitting it with your helmet?

Not the helmet he broke last night surely? 😉

😆 hope the tree is alright?