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Angle of Integrated Crown Race?

Old 04-18-23, 09:59 AM
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Angle of Integrated Crown Race?

I'm looking to replace the headset on my Cannondale CAAD Optimo 4. Is the 45 degree angle for the integrated crown race molded into the fork pretty standard? Is there a DIY way to do that measurement? Thanks for any advice!
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Old 04-18-23, 10:30 AM
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Crown races are typically either 36º or 45º Choose a headset that the maker specifies uses a 45º crown race.
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Old 04-18-23, 10:35 AM
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1- Are you sure the crown race seat is a 45* spec?
2- What does it mater what angle is "standard" as long as you replace with kind?
3- Some fork crown race seats are not meant to bare directly on the bearing's inner race but sit on a seating ring. This ring would need to both match the crown seat shape and the bearing's inner race angle which is likely either 36* or 45* (as these two angles are the most common).
4- The shop method of angle measurement is to take a known angle part and test fit it against the frame/fork seats (or the cups and rings that support the bearings). There have been at least one gage to measure some of the headset specs with (FSA's Headset Guide as example). However I don't remember it having a crown seat angle gage. What it does have is a bearing inner race seat angle gage, just measure what is currently in the bike. Andy

It would be easy to draw out a 45 or 36* angle on a piece of cardboard, cut this angle out and place it against the lower bearing's inner race seat.
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Old 04-19-23, 09:31 AM
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Originally Posted by Andrew R Stewart
Some fork crown race seats are not meant to bare directly on the bearing's inner race but sit on a seating ring.
What's this talk of bare bearings?
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Old 04-19-23, 03:25 PM
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Some cartridge bearing headsets have the lower stack's bearing sit directly on the fork crown's race seat with no pressed on race/seat. Since we were not told the brand or model of the OP's headset I mentioned this possibility.

In my world the bearing includes the two races and the balls/rollers between. Bare bearings could mean either individual balls (like is common in a loose ball bearing) or the cartridge bearing complete. Unsure which you refer to. Andy
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Old 04-19-23, 07:10 PM
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Originally Posted by Andrew R Stewart
Some cartridge bearing headsets have the lower stack's bearing sit directly on the fork crown's race seat with no pressed on race/seat. Since we were not told the brand or model of the OP's headset I mentioned this possibility.
I have a fork that has exactly that. The lower headset bearing cartridge sits directly on a "crown race" (36º in this case) molded into the fork's steerer base. No separate press-on race is needed.
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Old 04-26-23, 07:09 PM
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Thanks guys for the replies! I didn't think of just cutting out an angle and checking it against the bearing. I may even design one and 3d print it lol. Thanks again!
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Old 04-27-23, 10:42 AM
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The good news is that there are no close or easily confused angle standards.

So, use a protractor or sine chart and cut both angles into the corners of a piece of plastic, ie. a dead gift card. Then fit it to the crown and eyeball.
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