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How does 26.8mm relate to 1" threadless fork?

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How does 26.8mm relate to 1" threadless fork?

Old 11-30-10, 07:18 PM
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How does 26.8mm relate to 1" threadless fork?

I'm thinking about buying a particular 1" threadless steel road fork. I asked the seller what the crown race diameter was and now I realize I should have worded my question better. He responded 26.8mm. I'm assuming he's responding to what I meant to ask which was what crown race size is the fork compatible with, 27.0 or 26.4... The ID of my crown race must be 26.4 since it's stock from a common american road bike brand and the headset is "aheadset."

Anyway, what's the exact term for the part of the steerer tube/crown that the crown race presses onto? I checked sheldon brown's site... Would the diameter of that be 26.8 for a 1" threadless ISO fork? Could chrome or paint cause the diameter to be .3mm-.4mm larger than the race ID?
 
Old 11-30-10, 07:36 PM
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threadless forks don't have that 26.4mm or 27.0mm mix with ISO and JIS crown race inner diameter.

the crown race should always be 26.4mm on threadless forks. Well, it can be a bit larger, since it's supposed to be press fit, but it shouldn't be 26.8mm. You can always have a shop with the proper tools ream it down to a proper size.
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Old 11-30-10, 09:12 PM
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How accurate are his calipers? Or better yet, how accurate are the measurements he makes with them?
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Old 12-01-10, 11:54 AM
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Originally Posted by cachehiker View Post
How accurate are his calipers? Or better yet, how accurate are the measurements he makes with them?
Bingo!

It's close enough that I'd say you're safe to buy that fork. It doesn't take much of a twist of the calipers to make the dimension grow that much. Or much of a reading error if he's doing a quick measurement with an actual vernier scale set of calipers.
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