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Old 08-27-07, 08:40 AM   #1
kleng
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Dura-ace front hub - missing bearing

Hi

I was just servicing the front hub of my dura-ace 7801 wheelset and noticed that there are 16 loose bearings on each side with a gap. This means there is room for one more bearing on each side.

Can I just add another bearing or does the design only call for 16 bearings leaving this gap.
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Old 08-27-07, 08:44 AM   #2
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I may be mistaken, but I think there is supposed to be a gap for movement.
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Old 08-27-07, 09:47 AM   #3
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I believe you have just found the "n-1" rule of bearings. (n-2 for headsets I believe)
that is to say as many bearings as will fit or start to jumble and remove one. a search will probably tell you more, but for your purposes, the hub likely has the right number of bearings.
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Old 08-27-07, 10:47 AM   #4
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WH-7801 callout is for a retainer with 5/32" balls. I take it someone replaced it?

(Yes, use the n-1 rule if no retainer.)
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Old 08-27-07, 11:20 AM   #5
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There definitely should be extra room in there, just not a lot. 16 seems like a weird number to me, though. I thought bearing numbers went in 9s, 10s, or 11s?
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Old 08-27-07, 12:44 PM   #6
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HB-7800 hub takes 14 per side (loose). One I know takes 18. Kinda depends on ball size.
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Old 08-27-07, 02:35 PM   #7
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" Can I just add another bearing....."
You don't want to add 1 even if it needs it. Replace all of them from the same lot, so they match up.
IF 1 is a slightly different size, bad (grindy) things can happen.
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Old 08-27-07, 11:50 PM   #8
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