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| 3.0 Adjustable/Open BB |
| Advantages/Disadvantages |
| Cotterpins |
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BB - common acronym for Bottom Bracket.
“Cup and Cone” is another term used to describe a BB which has adjustable loose bearings. They are adjusted using the adjustable cup (on the non-drive side) which has a lockring to hold it in place after bearing adjustment. The oldest type of BB system still in use is an open bearing system. Cotterpin and Cotterless BBs come in to this category. (The term “cotterless” simply describes the lack of a cotterpin). Some types of BMX BB are also loose/open type.
Main Parts
- BB spindle
- The fixed cup The fixed cup (drive side)– as it name implies – is fixed into the frame and is not adjustable.
- The adjusting cup The adjusting cup (non-drive side)on the other hand can be tightened or loosened to make the BB run perfectly smoothly.
- Bearings.
Bearings
The bearings in an open/loose system can either be individual loose bearings or housed in a bearing cage. Either way, the bearings will run in between the cups and cones located on the spindle.
