Headset for frame with ~39.4 mm/~1 9/16" I.D. headtube?
 

OK, I have a frame I got cheap, but I can't figure out what size headset to put in it.

It's not designed for an integrated headset and the inside diameter of the head tube - as measured by a micrometer - is about 39.3 mm (just a bit under 1 9/16").

What size headset cups would fit? 1 1/8" cups have an outside diameter of 34 mm, 1 1/4" cups are 37 mm, and 1 1/2" cups are 49.6 mm.

FWIW, I have a 1 1/8" fork I'd like to use on the build - since I already have it.

My best guess is that u have to use in there a 1 inch semi integrated headset that is like 41 mm ID in the frame... my other guess is that you have to send that frame to get reamed too.

Read this meanwhile...

http://www.canecreek.com/manuals/Hea...ationGuide.pdf

No, it's definitely not an integrated 1" headset or semi-integrated one. I've dealt with those, and this head tube is nothing like that. The ends machined to a specific inside diameter at least 1" to 1 1/4" deep, and the "shelf" that is left is obviously not a bearing surface of any kind - in fact the machining reaches all the way to one of the holes made by either the top or down tube, so there's no way it could support an integrated headset of any type. It's just like a "normal" headset, just a weird size.

FWIW, the head tube outside diameter is about 45mm. The frame is a GT Legato, if that helps.

Maybe it's some variation on the onepointfive? See here: http://en.wikipedia.org/wiki/Headset_%28bicycle_part%29


It looks like reducers were available, but you'll have to hunt them down: http://www.e13components.com/zerosta...ucer_cups.html

Maybe try here: http://www.canecreek.com/headset-fit-finder

I thought I might have some reducing spacers that would work but it turns out they would fit a tube ID tube of about 43mm to 44mm (there is a gap in the ring). They fit a generic 1 1/8 headset once installed but the OD doesn't seem to match up to any of the standards you listed. They came off a Giant XTC frame that has since been sold. I don't remember what headset I put in there but I think I got it from Cane Creek. Just another data point FWIW.

OK, a bit of luck, and I ran across a mention of this frame (GT Legato 3.0) having something called an "Intellaset" for a headset. And lo and behold, my frame matches the specs for one "Intellaset" headset produced by FSA.

The headset seems to be a one-of-a-kind that's no longer made.

No wonder someone's dumping the frames.

Good luck man :) It would have help way more if the frame brand and model was mentioned from the 1st posting you know...


maybe....?

http://www.amazon.com/FSA-Intellaset.../dp/B001P9KQN6

http://www.ebay.com/itm/FSA-Intellas...item2568d32b2f

http://wheelandsprocket.com/product/...4643-qc263.htm

http://www.planet-x-bikes.co.uk/i/q/...ack---external

http://www.universalcycles.com/shopp...ls.php?id=5207

http://bikedoctorwaldorf.com/product...d4643-qc55.htm