Fork / headset headache: external cup headset, integrated crown race

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jever98
Posts: 936
Joined: Wed Feb 18, 2009 12:02 pm
Location: Seattle

Fork / headset headache: external cup headset, integrated crown race

Post by jever98 »

I have a carbon fork with an integrated heaset race: it's for a 1.5" lower bearing, but has a tapered bottom on the fork, that goes out from about 38.5mm to 48mm, and is about 7.5mm high.

I'm trying to install it on a frame with a 44mm headtube (press in headset), so was planning to use a Chris King headset with an external cup. The issue is that the chamfer on the inside of the bearing is too small. See pictures.

I'm at a loss as to which format headset would fit. It seems I need one with a bearing that has a longer (bigger) inner chamfer, if that makes sense.

Thanks for any tips

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joejack951
Posts: 746
Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE

Re: Fork / headset headache: external cup headset, integrated crown race

Post by joejack951 »

The bearing/headset cup combo you managed to find is very close to fitting. Perhaps a local machinist could cut the chamfer a bit deeper to make it work. I had this done to the outer race of some cartridge bearings for a custom headset I was working on. Some carbide tooling and a lathe made the job easy according to my machinist. Then again, he was cutting the outer race (easily held in a collet) and not the inner (not so easily fixtured).

Or search around and find a bearing with a larger inner chamfer but otherwise the same specs as the original CK bearing. You will likely need to email many Alibaba vendors before you find one that both answers your question and has the right bearing.

DJT21
Posts: 340
Joined: Sun Mar 27, 2011 7:35 pm

Re: Fork / headset headache: external cup headset, integrated crown race

Post by DJT21 »

If you have access to a lathe, could you not just file down the taper on the crown race area of the forks?

jever98
Posts: 936
Joined: Wed Feb 18, 2009 12:02 pm
Location: Seattle

Re: Fork / headset headache: external cup headset, integrated crown race

Post by jever98 »

Hi all,

thanks for the feedback. I was able to get the information on the bearing seat angle from the fork seller - it is 36 degrees. Cane Creek headsets all are 36 degrees (just found that out from them), so we're all good to go!
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