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BB30 and Shimano HTII Cranks

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BB30 and Shimano HTII Cranks

Old 04-23-15, 08:58 AM
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BB30 and Shimano HTII Cranks

I've been pondering a different solution to the wheels mfg adapters I'm using to fit my 5800 crank into my bb30 equipped frame. It's working fine at the moment, and I have no complaints, so this is all just hypothetical at the moment, opinions welcomed.

Has anyone ever heard of / seen a set of 61905-2RS bearings pressed into a bb30 BB shell? This bearing size is 42x25x9. Normal bb30 bearings are 7 mm wide, leaving room for an outer seal. According to the specs in this pdf https://www.bb30standard.com/wp-conte...andard_new.pdf these bearings would extend past the edge of the bb shell by ~ 1mm, depending on the tolerances. A normal shimano BB is 90mm wide. these bearings would make the bb shell width ~ 70mm wide, leaving a nice tidy 10mm worth of spacers on each side. The 25mm ID bore would need a sleeve to reduce to 24 mm, but this is the same thing shimano does with its bottom brackets as it is.

The upsides: Larger bearing, native interface, permanent
The downsides: uncommon, unknown, potentially heavier, removing/installing new bearings, ect..

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Old 04-23-15, 09:09 AM
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You'd need to install spacers as the spindle on a HTII crank would be too long for BB30 without them.

EDIT: apparently I need to read your post better.
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Old 04-23-15, 02:00 PM
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they'll be heavier (probably inconsequential), no doubt and there would appear to be 2mm of each bearing that will be unsupported by the BB shell, in addition to the 10mm per side of unsupported (unlike the shimano design with the screw-in external bearings) extra leverage that is not common to a BB30 installation that uses a 68mm wide shell. plain spacers, if i understand your intentions, won't have any support.

may be worth a try though. good luck.
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