BB 30

"BB 30" almost certainly refers to the BB30 bottom bracket standardfor bicycles. It's a very common term in the cycling world.

Here’s a breakdown of what it means:

What is BB30?

It's a standard for the interface between the bicycle frame and the crankset. The "BB" stands for Bottom Bracket, and the "30"refers to the 30mm diameter of the spindle (axle) that runs through the crankset.

Key Features:

1. Larger Spindle (30mm):Compared to the older 24mm spindle standard (like Shimano's Hollowtech II), the 30mm spindle is stiffer, which can improve power transfer and reduce flex.
2. Press-Fit Design:The bearings are pressed directly into the frame's bottom bracket shell, which is 42mm in diameter. This eliminates the need for threaded cups and can save weight.
3. Wider Bearing Placement:The bearings sit further apart (68mm or 73mm shell width), which can also contribute to stiffness and durability.

Advantages:

• Increased stiffness and potential power transfer.
• Lighter weight (no threaded metal cups).
• Allows for narrower "Q-factor" (pedal stance width).

Disadvantages & Common Criticisms:

• Creaking:This is the most notorious issue. If the tolerances between the bearing and the frame aren't perfect, the press-fit interface can develop creaks and clicks under pedaling load.
• Compatibility:Requires specific frames, cranks, and bearings. You can't put a BB30 crank into a threaded bottom bracket frame without an adapter.
• Bearing Life:Some users report shorter bearing life, as the bearings are pressed directly into the frame (sometimes with plastic adapters) and are smaller in diameter.

Important Related Standards (Often Confused):

• PF30:A variation where the frame shell is 46mm, and the bearings are pressed into plastic cups, which are then pressed into the frame. Designed to combat tolerance/creaking issues of BB30.
• BB30A:A wider version (73mm shell) used by some brands like Cannondale on their road bikes.
• BB386EVO:Another wider standard (86.5mm shell width) that uses a 30mm spindle but allows for even greater design flexibility.

In Summary:

If you're dealing with a bike component, maintenance, or a new purchase, BB30refers to this specific press-fit, 30mm spindle system. When buying a crankset, bottom bracket, or a new frame, knowing your BB standard is crucial for compatibility.

Is this the "BB 30" you were asking about? If you have a specific situation (like installing a crank or dealing with a creak), I can provide more detailed help!