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Discussion Starter · #1 ·
Would anybody know what is the standard dimensions of Campy (Record or Chorus) threadless 1" headset? Park tools list two standards:

1. One-inch "Japanese Industrial Standard" (JIS):
  • Common on many Asian manufactures bicycles, both road and MTB
  • Fork column outside diameter- 25.4mm (1")
  • Head cup race OD- 30.0mm
  • Acceptable head tube ID range- 29.75mm to 29.9mm
  • Fork crown race ID- 27.0mm
  • Fork crown seat OD acceptable range- 27.1mm to 27.2mm
  • Threadless stem diameter- 25.4mm (1-inch)
2. One-inch "Modern European" Standard:
  • Many road bike and some MTB bikes
  • Fork column outside diameter- 25.4mm (1-inch)
  • Head cup race OD-30.2mm
  • Acceptable head tube ID range- 29.9mm to 30.1mm
  • Fork crown race ID- 26.4mm
  • Fork crown seat OD acceptable range- 26.5mm to 26.7mm
  • Threadless stem diameter- 25.4mm (1-inch)

It looks to me that most 1" forks in US are the "Modern European" standard since the fork crown races are 26.5 mm. I think even Chris King threadless 1" headset is this standard since it requires head tube dia = 30.1 mm and fork race = 26.5 mm.

Thanks,
Bo
 

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Master Bike Mechanic
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Yep, if you have a fork made in the last ten years it most likely uses the "Modern European" Standard, which is also know as 1" ISO standard (International Standards Organization or something like that.)

Although I have recently ran into two Italian built frames that use the JIS standard size, which were incompatible with my ISO Suntour Headset, so since it's the Crown Race size that was causing trouble I just hopped up to the LBS and got a cheap used fork, and it's fine now.
 

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Discussion Starter · #3 ·
Thanks!
Are you saying that current Campy is ISO? I searched their web but did not find any confirmation. So if somebody could confim that their 1" headset fits 26.5 mm fork crown it would help!!
Bo
 

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Master Bike Mechanic
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According to <a href="http://aebike.com/page.cfm?PageID=30&action=list&Category=600&Brand=60&type=T">Alfred E. Bike</a href>, the Campy Chorus and Record 1" threadless and threaded Headsets use the ISO Standard of 26.4 for the Crown Race. If your fork is 26.5 then it will work, but it will be VERY though to get the race on.

If you don't have the right tool to install the race my technique is to take a vice, put the race on the steerer and tighten the vice just to the size of the steerer (For one inch I'd place it at around 25.7 mm.) I place a section of wood on the underside of the crown, and whack it with a hammer till the race is seated. This way you don't damage the race by using a flat head screw driver and a hammer like some people I know. But please don't try this with a Carbon steerer tube, in fact, I'd be hesitant to do so with a Aluminum one.
 
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