Bicycle Mechanics - Difference BB 30 & "other" bb

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View Full Version : Difference BB 30 & "other" bb


Lawrence08648
07-12-10, 01:22 PM
I've changed my bottom bracket over the years several times and now am using ISIS.

I know what BB30 is but I've never seen a frame that is setup for the BB30 without it.

Am I getting the impression that a bike frame has to be built for the BB30? and no other BB can be used? If so, this means I can't decide to put a BB30 on my bike that is currently using ISIS?

Looking at the bb frame, what does the setup for a BB30 look like? How does it differ from the "normal", such as the threaded bb for using ISIS, Octalink, etc.


CACycling
07-12-10, 02:16 PM
BB30 uses a completely different BB shell. It is larger diameter and narrower than what you are used to seeing.

cycle_maven
07-12-10, 02:50 PM
No, a standard frame can't use a BB30 bottom bracket. It's way different- larger diameter with bearings that are pressed right into the frame.

If your frame is already BB30, you can get an adapter that converts it to a standard english bottom bracket. I don't know why anyone would do that, but it's possible.


Lawrence08648
07-12-10, 07:28 PM
The bearings pressed in? I thought the bearings were on the outside? If I have a bike that is BB30, is replacing the bearings something I can do myself? On a replacement or just a frame, are the bearings something I can press in using a C clamp? Is this something most bike shops would have the tool to press the bearings in?

operator
07-12-10, 08:00 PM
The bearings pressed in? I thought the bearings were on the outside? If I have a bike that is BB30, is replacing the bearings something I can do myself? On a replacement or just a frame, are the bearings something I can press in using a C clamp? Is this something most bike shops would have the tool to press the bearings in?

A high end shop will have tools to deal with BB30. It's not extremely common yet so I doubt most regular road shops will have the tools to service it.

fietsbob
07-12-10, 11:43 PM
external bearing crank, but the frame was made wider so the big diameter bearings, with lots of little balls is back internal in the frame.

Kind of like a 3 piece crank adapter for an American One piece crank Frame.
if you want to use older spline or square taper BB's back in the day

perhaps look for a Normal BB frame ... How about a metal one?

operator
07-13-10, 12:08 AM
external bearing crank, but the frame was made wider so the big diameter bearings, with lots of little balls is back internal in the frame.

Kind of like a 3 piece crank adapter for an American One piece crank Frame.
if you want to use older spline or square taper BB's back in the day

perhaps look for a Normal BB frame ... How about a metal one?

Looks like somebody was smoking a bit too much pot today.