ok so i have heard rumours that its possible to get an external 1.5 headset into a semi-intergrated headtube.
anyone have any experience of this?
ive seen a pic of a bike this has been done to but im unsure of how much machining went on to achieve it.

Use a bigger hammer than usual?

I have done it, depends on frame as to whether machining is required.

I have an iron horse MkIII and bought the Nuke Proof headset

http://www.chainreactioncycles.com/Models.aspx?ModelID=60615

To allow me to fit tapered Rock Shox Revs. For my frame the lower cup was too big, it had a 20mm flange and my frame would accept 10mm of insertion. I got the machinist at work to pop it in the lathe and he took the outside edge of it down to 10mm and tapered it up as per the original design. It took him 5-10 minutes max, cost to me was a packet of chocolate biscuits.

At some point in the future I believe Nuke Proof will be selling the non-oversised flange models but I have no idea when.

One thing I would advise getting is a set of digital callipers like these from Lidl on sale from tomorrow so when it comes to you taking the parts to a machine shop you will have accurate, measurements for them to work to.

http://www.lidl.co.uk/cps/rde/xchg/lidl_uk/hs.xsl/index_19198.htm

micrometer screw guage is needed for sufficiently accurate measurements and any decent engineer should have them (and the specs will be available online Shirley?)

Al I don’t see how a micrometer screw guage is relavant in the slightest for this application. You use the calipers to measure the depth of possible cup insertion. The frame will be 44mm ID the headset will be the correct OD for the frame, the measurement of concern will be the insertion depth which the claipers will allow the op to measure accurately enough.

Specs online will most likely tell the op he has a 44mm head tube which unfortuneately doesn’t mean it has 44mm ID for it’s entire length.

jonah tonto

If anything i have written doesn’t make sense my email is in my profile i can try and explain it in a different way.

thats great rusty, i figured it was possible, i just wanted a bit of reassurance cos i have been known to take things too far when modifying. i already have a set of those calipers, they have been very handy lots of times, ill be giving it a go.
that is when i fix my frame as i snapped a bit of it while up whytes this evening 😥