External BSA Bottom Brackets

Product Details

White Industries external BSA style bottom brackets are made here in our shop and feature Enduro stainless steel angular contact bearings or optional Enduro XD-15 ceramic-hybrid radial bearings.  We offer them with three different bearing sizes to help you fit your favorite crank to your favorite bike. “BSA” bottom bracket shells and cups are named after the Birmingham Small Arms Company which created the thread standard used in this system.  It’s also referred to as “British” or “English” style and is the most common type of system found on modern bicycles.  The “external” designation refers to the fact that the bearings will sit outboard of your frame’s bottom bracket shell as opposed to being tucked inside the shell as you would find on some styles of BSA bottom brackets.  

Specs

• 1.37” x 24 TPI threads ("BSA" threads)
• Designed to be used on 68mm or 73mm wide bottom bracket shells
• Enduro stainless steel angular contact bearings
  • Enduro XD15 ceramic-hybrid bearings optional
• Weight/pr (with bearings and seals)
  • 30mm: 83g
  • 29mm: 90g
  • 24mm: 84g
• Cup widths (external section of each cup, including seal)
  • 24mm: 10.5mm
  • 29mm: 11.5mm
  • 30mm: 11.5mm
• Thread depths
  • 24mm: 11mm
  • 29mm: 13mm
  • 30mm: 13mm
• Bearings
  • 24mm: Enduro SMRA 2437 LLB or CXD MR 2437 LLB
  • 29mm: Enduro S71806/29 LLB or CXD 6806/29 LLB
  • 30mm: Enduro S71806 LLB or CXD 6806 LLB
• Torque: 26-37 ft lbs (35-50 Nm)
• Anodized with machine engraved logos
• Available in black, blue, gold, pink, purple, polished silver, red

Compatibility

• Designed to be used on threaded BSA 68mm or 73mm wide bottom bracket shells
• Comes in three bearing sizes to fit:
  • 30mm White Industries MR30 series cranks as well as other brands of 30mm spindle cranks
  • 29mm SRAM DUB cranks as well as other brands of 29mm spindle cranks
  • 24mm Shimano HollowTech II road and mountain cranks as well as other brands of 24mm spindle cranks
  • Not compatible with square taper style spindles
• Tools: see the Bottom Bracket Tool Compatibility document

How many spacers?

White Industries cranks

• No spacers needed with White Industries R30 and G30 cranks on 68mm shells
  • 73mm shells are too wide to use with these models
• No spacers needed with White Industries M30 and A30 cranks on 73mm shells
  • On 68mm shells, use one 2.5mm BSA cup spacer or one 2.5mm x 30mm spindle spacer on each side

For other manufacturers' cranks it's very hard to estimate exactly how many spacers you might need.  Most cranks these days have an adjustable bearing preload collar on them that can accommodate slightly wider/narrower "Outer Bearing Width" (OBW) than their target number, but you'll need to check with your particular crank's manufacturer. When in doubt, start with few spacers than you think you need so you don't crush and destroy your bearings! 29mm SRAM DUB cranks

• SRAM DUB 29mm spacers are not compatible with our BSA 29mm bottom bracket
  • Spacer kits available under Parts>Bottom Bracket Parts>Bottom Bracket Spindle Spacer Kits
• Using SRAM's charts, look at the BSA row, find your shell width, find your crank model, then see what spacers they require
  • SRAM DUB road crank spacer chart
  • SRAM DUB mountain crank spacer chart
• Our cups are .5mm wider (each) than SRAM DUB cups so take this into account when estimating spacers

24mm Shimano HollowTech II cranks

• Our cups are the same width as Shimano mountain BB cups (10.5mm each)
• Our cups are 1mm narrower (each) than Shimano road BB cups
• In either case you will normally not need spacers

What’s In The Box

• Left and right threaded BSA cups with bearings installed and two external seals
  • Seals should sit directly against the bearings, with the part numbers (molded into the seal) facing out
• Cup or spindle spacers not included
• Sleeve not included (not currently available)

Technical Documents

• MR30 Crank and Bottom Bracket Compatibility Chart
• Bottom Bracket Tool Compatibility
• MR30 Crank Assembly