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BB90 is "tight" and crank doesn't spin completely freely

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BB90 is "tight" and crank doesn't spin completely freely

Old 07-02-19, 03:40 PM
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BB90 is "tight" and crank doesn't spin completely freely

Installed a replacement BB90 in my Trek Boone. After cleaning everything and installing the new BB, the FSA crank is ever so slightly resisting rotation (no chain is on the bike yet). Even before I attach the NDS pedal, it's slightly "tight" feeling - so it's not from compression. I feel like I should be able to give it a spin and it should spin around a time or two before stopping. Instead it won't move unless I give it a slight pressure. Is it possible that one side or other of the BB has slight "toe" (car lingo) and is not spinning smoothly?

I brought it over to LBS and he said "sometimes they start out a bit tight" and it may free up after riding a bit. But this sounds...fishy...to me. I feel like when a new bearing is installed it should be smooth as butter on glass...

Is it possible that it's not the right BB? The crank fits, even greased, and the BB sits nice and flush in the frame on both sides.
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Old 07-02-19, 05:07 PM
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The cartridge seals create some drag, which may be what you're feeling. Seal drag is utterly insignificant under load and as the shop said, over time the seals will wear in and the spindle will exhibit less drag.
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