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Headset Crown Race Size

Old 10-29-21, 04:33 PM
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saias
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Headset Crown Race Size

I searched the forums and read Sheldon's cribsheet and Park Tools articles on headset sizing, but I'm still confused and having trouble.
I'm replacing the headset on my Panasonic which has a Tange fork. I'm replacing because the steering is "indexed". It's from the late '80s so figured it was using the 1" standard rather than the JIS size. The size on the new headset is 30.2/26.4. The crown race is just not going on. The old one goes on no problem. I should probably get some calipers to take measurements, but want to check here if anyone would be able to confirm the crown race size for a Japanese bike from this period.
I have not tried the cups yet. Would the cups be JIS as well if the crown race is JIS, or is it possible that it is mixed sizing?
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Old 10-29-21, 05:43 PM
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I made the same mistake years ago, then bought calipers to always measure and be certain. The cup diameters are so close (30.0 JIS / 30.2 ISO) that I don't think it's an issue to mix and match. If your original crown race isn't pitted, I'd say it's worth a build up to see how it fits/works.

What brand/model headset did you buy? And what was on there before?
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Old 10-29-21, 05:58 PM
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The new headset is a Tange Falcon. The original is also Tange.

The races don't look bad at all. No pitting, and I see only the faintest of indentations. I was surprised because the index on steering was quite noticeable. It would almost snap to center. I have not inspected the bottom cup yet, but would that cause indexing? I'm starting to think the previous owner may have worked on the headset and installed a bearing cage the wrong way.
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Old 10-29-21, 06:07 PM
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Originally Posted by saias View Post
The new headset is a Tange Falcon. The original is also Tange.

The races don't look bad at all. No pitting, and I see only the faintest of indentations. I was surprised because the index on steering was quite noticeable. It would almost snap to center. I have not inspected the bottom cup yet, but would that cause indexing? I'm starting to think the previous owner may have worked on the headset and installed a bearing cage the wrong way.

Looks like you bought a cartridge bearing headset and I'm guessing the original is not, which makes me doubt the old race will work with new headset. Are you not able to return/exchange it?

Pitting anywhere will cause indexing, BUT so will over-tightening things. If there's no pitting on any of the cups/races, then I'd guess it was just too tight.
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Old 10-29-21, 06:16 PM
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Originally Posted by squarenoise View Post
I made the same mistake years ago, then bought calipers to always measure and be certain. The cup diameters are so close (30.0 JIS / 30.2 ISO) that I don't think it's an issue to mix and match. If your original crown race isn't pitted, I'd say it's worth a build up to see how it fits/works.

What brand/model headset did you buy? And what was on there before?
this... .just had this issue close but no cigar between JIS and ISO
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Old 10-29-21, 06:19 PM
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Yeah, it's cartridge. It would be returnable, but you can tell I tried to install it. I will just hold onto it for the next bike.
I will reinstall the original headset. Fingers crossed it was just too tight.
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Old 10-29-21, 06:26 PM
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Originally Posted by saias View Post
Yeah, it's cartridge. It would be returnable, but you can tell I tried to install it. I will just hold onto it for the next bike.
I will reinstall the original headset. Fingers crossed it was just too tight.
Good call and best of luck. Report back with how it works out. Fingers crossed you have a headset wrench to dial it in just right. It can be tricky without one.
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Old 10-30-21, 09:47 AM
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Japanese bikes of that era are likely to use JIS spec headsets: 30.0mm pressed head tube pieces and 27.0mm crown race, rather than ISO 30.2mm and 26.4mm. Tange headsets are made in both JIS and ISO spec for each model; you bought the ISO version. All is not lost, though: JIS spec head tubes and crown race seats are easily milled to ISO spec by a properly equipped bike shop.
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Old 10-30-21, 12:49 PM
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Originally Posted by squarenoise View Post
Good call and best of luck. Report back with how it works out. Fingers crossed you have a headset wrench to dial it in just right. It can be tricky without one.
I have the original headset installed and it's all good. I took it to the LBS to set it. Smooth turning and no play. Thanks for your help.

Originally Posted by JohnDThompson View Post
Japanese bikes of that era are likely to use JIS spec headsets: 30.0mm pressed head tube pieces and 27.0mm crown race, rather than ISO 30.2mm and 26.4mm. Tange headsets are made in both JIS and ISO spec for each model; you bought the ISO version. All is not lost, though: JIS spec head tubes and crown race seats are easily milled to ISO spec by a properly equipped bike shop.
I found out the hard way, but do appreciate you confirming the size. For some reason I thought Japanese bikes moved on from the JIS spec in the 70s.
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Old 10-30-21, 02:13 PM
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Nice! Happy to hear it worked out.
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