Headset help

[Tom79]

I have a 1996 P7...or at least I am pretty sure its a 96. Anyway, I have some threadless RC35 with a 1" steerer, have removed the old threaded headset and need a new threadless one.

However I'm a little confused with the ID/OD sizes...and what it is I need. Seems like there is variation in 1" headsets - I guess I need to know all these other measurements on the bike and the fork and it's not just as easy as getting a 1" threadless headset?!

Excuse the ignorance, still learning

 

[rocky ridge]

its the fork crown race size thats different
eg 26.4mm crown or 27 mm crown
some better quality crown races have the size stamped underneath
if you dont know the crown race is the very bottom part of the headset thats attached to the fork
the small ring that you had to knock off the forks with a screwdriver drift etc

 

[Tom79]

Cool thanks. So if it's the crown race that's different then I need to measure the fork in order to get the right size? Just need to know what measurements I need when I buy a new headset....

 

[WD Pro]

If you have mix n matched frame and forks, you might need to mix n match headsets ...

Get some calipers and check both

 

[raymondluxuryyacht]

I think you are talking about Iso 1" vs jis 1". Former is a 26.4 internal diameter on the crown race of the headset and the latter is 27.0. Just google "iso headset sheldon brown" to see what I mean. I'm pretty certain a normal frame and fork p7 would be ISO. However if you have a much older fork than the frame or its far eastern made then this increases likelihood the fork could be designed for a jis headset with 27.0 internal diameter to the crown race. I'd be pretty surprised if a Pace fork was anything other than ISO. I got a cane creek threadless 1" off ebay and the seller was able to identify it as 26.4. If I can find his details I'll let you know.

 

[raymondluxuryyacht]

seller was "highonbikes"

 

[Tom79]

seller was "highonbikes"

Nice one, thanks for that!