Is it possible to remove the bearings from one bike's bb and put them on to another or would using a tool such as the Park tool bbt 90.3 damage them somehow?
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Blue Bicycle Book by Calvin Jones, as well as many other sources of information about bicycle maintenance, advise against reusing any bearings that were previously pressed in somewhere (bottom bracket, headset, hubs etc.)– Grigory RechistovCommented Nov 12, 2018 at 16:37
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2 Answers
The major concern is that whenever the inner race gets loaded to extract the bearing, it's subject to getting damaged. BB86 and BB92 cups don't get removed by bonking the inner race, rather the plastic cup, and so if one of those types of bottom bracket felt good before removal, I think re-using it is fine. The "rocket ship" type tools (Park BBT-90.3) do have the ability to chew up the plastic cups where they make contact, and I've seen this be significant although it usually isn't. Usually the interference fit is pretty "gentle" on BB86 and BB92.
All of the systems that involve bearing cartridges pressed directly into the frame (BB30, BB90/95, others) are prone to the bearing race surfaces getting damaged during removal. If you were to reinstall them there might be notchiness and drag, and probably to some degree will be. That doesn't mean they won't have any kind of service life at all. If the bearings were clearly in good condition when you started, and it's your own bike or a charity case, re-pressing them may be reasonable. It's a judgment call and you may not like the result, or it may be fine. A shop doing it for a paying customer would be bad.
answered Nov 12, 2018 at 17:46
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Great answer, I like the pragmatism shown at the last sentences.– mattnzCommented Nov 12, 2018 at 19:59
According to GCN and their video on press fit BB removal, press fit bearings are not designed to be removed and re-used.
If the inner race is being impacted by the tool during removal, there definitely is potential for damage as obviously force is being transmitted through the bearing races and balls and the race surfaces could be deformed.
Looking at the Park Tool BBT-30.4 it obviously contacts the inner race of BB30 bearings.
answered Nov 12, 2018 at 12:45
