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Crown race fit question

Old 07-05-22, 06:54 AM
  #1  
hhk25
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Crown race fit question

I changed forks on a bike recently and on the new fork, the crown race (from the old fork) slipped into place on the steerer tube without much effort. In other words, I pushed it down by hand instead of using the crown race setting tool. There didn't appear to be any perceptible movement in the race but I'm wondering if I should be concerned about this. Every other crown race I've installed was a tight fight and had to be tapped down using the tool.

Maybe I'm worried about nothing and the compression from the top cap will tighten up the race? Or should I be looking to replace the race?
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Old 07-05-22, 07:49 AM
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Are the forks both milled for the same size crown race? If itís a 1Ē steer tube, you might be switching from a 27mm to 26.4mm race seat, in which case Iíd replace the crown race with the proper size. Or if itís a 1 1/8Ē steer tube, is the new crown race the split type? These are made to slide on without a tool.
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Old 07-05-22, 08:05 AM
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Was the fit of the crown race on the new steerer a modestly firm push fit or sloppy fit? If it took a reasonably firm push you should be fine. If it was a 27.0 race on a 26.4 steerer the fit would be noticeably sloppy. As to a split crown race, the OP just transferred the old race to the new fork so that isn't the issue unless the old race was already a split type.
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Old 07-05-22, 08:18 AM
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Using digital calipers, the old fork is 30.08mm. The new fork (I have a second uninstalled, identical fork) measures about the same. Give or take .02mm. Iím assuming any difference is just error created by how hard I push the calipers jaws.

I think Iím okay. Whatís the worst that can happen? Damage the race and bearings?
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Old 07-05-22, 08:20 AM
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I suspect (from what the OP says) that both forks were machined for the same crown race diameter fit but the replacement fork was cut a tad too small. (This is not uncommon with hand driven machining).

Two options are dimpling the crown race diameter with a center punch in a number of spots around the steerer and/or using a retaining compound (LockTite 609 or equivalent). Andy
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Old 07-05-22, 09:17 AM
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Originally Posted by HillRider View Post
Was the fit of the crown race on the new steerer a modestly firm push fit or sloppy fit? If it took a reasonably firm push you should be fine. If it was a 27.0 race on a 26.4 steerer the fit would be noticeably sloppy. As to a split crown race, the OP just transferred the old race to the new fork so that isn't the issue unless the old race was already a split type.
Modestly firm and the race was not the split type.
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Old 07-07-22, 07:05 AM
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A bearing retaining compound, as Andrew suggests above, would work. E.g. Loctite #609. Stein makes a knurling tool to slightly increase the diameter of the race seat to fix this issue, as well. Probably not cost-effective for a one-off job, but perhaps a local shop may already have one and do the work for you?


https://steintool.com/portfolio-items/knurling-tool/
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Old 07-07-22, 08:02 AM
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Check with the headset mfr. I know Chris King sold slightly undersized races for their HS but you had to contact them directly to get the info. and possibly the same for other mfrs.
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