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9 votes

Why were press fit bottom brackets invented?

Carbon is the dominant frame material in performance bicycles. You can't thread carbon. There are two ways to get bottom bracket cups into a carbon frame: bond (industrial-strength glue) an alloy ...
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  • 20.3k
4 votes

Why were press fit bottom brackets invented?

The reason I have always heard justifying PF bearings vs outboard bearings is that PF bearings allow the frame to be wider and stiffer in the BB area without increasing the Q-factor of the bicycle. PF ...
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4 votes

Why were press fit bottom brackets invented?

Money. Threading holes is a process that has to happen during manufacturing. Both sides have to be concentric and parallel, and the taps used to make the threads have to be pretty good, so they wear ...
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  • 101k
4 votes

Is ISIS compatible with BSA?

BSA refers to the diameter and thread pitch of the threaded bottom bracket shell in the frame. Square Taper and ISIS refer to the crank interfaces on the ends of the axle of cartridge bottom brackets (...
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3 votes
Accepted

Can BSA 68/73 bottom bracket be used in place of fat bike BSA 100 mm

The spacing is the only difference across the SRAM/TRUVATIV GXP line of BB's, so yes, you can use the 68/73mm left/right cup set on your frame. Just reuse the center seal/spacer from your existing BB, ...
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  • 553
2 votes
Accepted

Crankset compatibility: Specialized Stout XC vs. SRAM GX 1000 GXP

The parameters involved are as follows: Your frame’s bottom bracket shell, which is BSA threaded. The spindle type, which is where you ran into trouble. Shimano specifies a 24mm diameter spindle. ...
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  • 20.3k
2 votes

Will my chain line be affected if I use a BB386EVO crankset on a standard cartridge BSA frame?

BSA or 'English' or ISO standard refers to the the thread in the bottom bracket shell (1.37in x 24 TPI). Both cartridge and external bearings fit in this these shell threads. There are several ...
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1 vote

Why were press fit bottom brackets invented?

With threaded bearings the actual bearings first have to be pressed into the threaded aluminum cups. They are then screwed into the frame. This is quite unusual, usually bearings are directly pressed ...
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  • 20.3k
1 vote

BB30 to BSA frame conversion with internal cable routing?

In the first picture it looks like the holes are simply machined to decrease the weight of the adapter without compromising strength. My only concern with the frame and adapter would be tolerances ...
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