Bottom Bracket Tool Selection: Threaded and Thread-Together

There are many different brands and models of bottom brackets as well as many variations on tool fittings for their service. This article will review the selection of Park Tool options for various bottom bracket systems in threaded frame shells and for thread-thru bottom brackets. For a review of the various bottom bracket standards, see Bottom Bracket Standards and Terminology.

1

Preliminary Info

What Tools do I need?

To determine the correct tool, begin by inspecting the bottom bracket. In some cases it will be necessary to remove the crank in order to measure and determine the tool choices.

If there are no tool fittings visible it is likely a press fit bottom bracket. See Bottom Bracket Tool Selection: Press Fit.

Press fit bottom bracket adaptor installed in bottom bracket shell of carbon fiber bicycle frame
Press fit bottom bracket showing no tool fittings

If the bottom bracket is installed and removed using threads, there will be tool fittings visible. This is also the case for frames using press fit shells and a “thread-together” bottom bracket, also known as a “thread-thru”. For purposes of tool selection, a thread-together bottom bracket is treated the same as a threaded bottom bracket.

Tool fittings can be notches or indentations on the outer perimeter, splines on the inside perimeter, or pin holes on the face. Count the number of tool fittings on the cup.

Head-on view of bottom bracket cup with arrow indicating starting point and lines indicating counted notches
This cup has 16 notches as tool fittings

Next, use a caliper to measure the diameter or width of the tool fittings. For external notches, first measure the outer diameter of the bottom bracket cup or adapter as seen below. This is the major diameter of the tool fitting. Next, measure from the inside of one notch to the inside of the notch directly opposite. This is the minor diameter of the tool fitting.

Digital caliper measuring outside diameter of external bottom bracket cup mounted to bottom bracket shell
Measuring the major diameter of the cup

Although the tools fit at the inside portion of the external splines, measuring the outside will be enough to differentiate the standard.

For tool fittings on the inside perimeter, measure to where the tool would fit as seen in the image below.

Digital caliper measuring overall diameter for bottom bracket with internal tool spline fittings
Measuring an inside diameter tool fitting.

It can be difficult to get exact measurements. For most models, getting within a millimeter will be good enough to get the correct tool.

2

Tool Finder Table

Use the table below to find the best match, and click the name of the tool to see an example of the tool fitting as well as a list of popular brands that feature this fitting. There are also some proprietary styles not listed here.

Flats/Pin Holes/Splines

Tool Fitting Dimension Tool
2 flats 16 mm widthHCW-11
2 flats 36 mm width HCW-4
4/6/8 pin holes 3 mm hole SPA-1
12 internal splines 23 mm ID BBT-5/FR-11
20 internal splines 31.5 mm ID BBT-22, BBT-32

External Notches

Tool Fitting Major Diameter Minor Diameter Tool
3/4/6/8 external notches 44–46 mm OD

~40 mm OD

HCW-5
6 external notches 43–44 mm OD

38 mm OD

BBT-4
8 external notches 40–45 mm OD

38mm OD

BBT-18
12 external notches 45–47 mm OD

44 mm OD

BBT-79
12 external notches 48–50 mm OD

46.3 mm OD

BBT-35
12 external notches 50–53 mm OD

48.2 mm OD

BBT-47
16 external notches 39–40 mm OD 37.6 mm OD BBT-49.2, BBT-29
16 external notches 41–42 mm OD

39 mm OD

BBT-59.2
16 external notches 44–45 mm OD

42.7 mm OD

BBT-69.2, BBT-19.2, BBT-9
16 external notches 48–50 mm OD

46.4 mm OD

BBT-27.2, BBT-29
16 external notches 52–54 mm OD

48.8 mm OD

BBT-47
24 external notches 45–47 mm OD

44 mm OD

BBT-79
36 external notches 51–53 mm OD

50.7 mm OD

BBT-35
3

Tool Fittings

2 Flats, 16 mm Width

Closeup of bottom bracket up with two wrench flats, installed in bottom bracket shell

2 flats on adjustable cup

The Park Tool HCW-11 Adjustable Cup Wrench

Park Tool HCW-11

Examples include adjustable bottom bracket non-drive-side cups using two wrench flats at 16mm.

Use the Park Tool HCW-11


2 Flats, 36 mm Width

Bottom bracket cup with two wrench flats on outer perimeter, installed in bottom bracket shell

Bottom bracket cup with two wrench flats

The Park Tool HCW-4 Crank and Bottom Bracket Wrench

Park Tool HCW-4

Examples include many adjustable ball bearing bottom brackets using a drive side (right side) cup with two wrench flats spaced at 36mm.

Use the Park Tool HCW-4


4/6/8 Pin Holes

Bottom bracket cup with 6 pin holes, installed in bottom bracket shell

Pin holes in left cup

The Park Tool SPA-1 Pin Spanner

Park Tool SPA-1

Examples include many adjustable ball bearing bottom brackets using a non-drive (left side) cup with 4, 6, or 8 pin holes.

Use the Park Tool SPA-1


3/4/6/8 External Notches, 44–46 mm OD

Adjustable cup bottom bracket lockring with 6 external notches, installed in bottom bracket shell

External lockring of adjustable cup bottom bracket

The Park Tool HCW-5 Bottom Bracket Lockring Wrench

Park Tool HCW-5

Examples include adjustable cup-and-cone bottom brackets with left side outer lockring.

Use the Park Tool HCW-5


6 External Notches, 43 mm OD

Cartridge bottom bracket with 6 external notches, installed in bottom bracket shell of gray alloy bike frame

6-notch cartridge bottom bracket

The Park Tool BBT-4 Bottom Bracket Tool

Park Tool BBT-4

Examples include Campagnolo® cartridge bottom bracket using six radiused tool fittings.

Use Park Tool BBT-4


8 External Notches, 40–45 mm OD

Cartridge bottom bracket with eight external notches, installed in bottom bracket shell on gray alloy frame

8 external notches

The Park Tool BBT-18 Bottom Bracket Tool

Park Tool BBT-18

Examples include Truvativ® Giga Pipe™, Bontrager® and others.

Use Park Tool BBT-18


12 Internal Splines, 23 mm ID

Cartridge bottom bracket with 12 internal splines, installed in bottom bracket shell on gray alloy bike frame

12 internal splines

The Park Tool BBT-5/FR-11 Bottom Bracket Tool

Park Tool BBT-5/FR-11

Examples include Campagnolo® Centaur®, Chorus®, and Record® Track, as well as Miche® square spindle models. The tool fitting is the same as the Campagnolo® cassette lockring tool.

Use Park Tool BBT-5/FR-11


12 External Notches, 45–47 mm OD

Threaded bottom bracket cup with 12 external notches, installed in bottom bracket shell on gray alloy frame

12 external notches, 45–47 mm outside diameter

The Park Tool BBT-79 Bottom Bracket Tool

Park Tool BBT-79

Examples include Race Face® Cinch®, Rotor® 30, and others.

Use Park Tool BBT-79


12 External Notches, 48–50 mm OD

Threaded bottom bracket cup with 12 external notches, installed in bottom bracket shell of carbon fiber frame

12 external notches, 48–50 mm OD outside diameter

The Park Tool BBT-35 Bottom Bracket Tool

Park Tool BBT-35

Examples include Praxis Works® M30 bottom bracket cup.

Use the Park Tool BBT-35
Note: This is a double-sided socket with 12 notches at 48mm and 18 notches at 51.7mm


12 External Notches, 50–53 mm OD

Threaded bottom bracket cup with 12 external notches, installed in bottom bracket shell of red alloy frame

12 external notches, 50–53 mm outside diameter

The Park Tool BBT-47 Bottom Bracket Tool

Park Tool BBT-47

Examples include Chris King® ThreadFit™ 30, Wheels Mfg™, and others.

Use Park Tool BBT-47
Note: This is a double-sided socket with 16 notches at 52.2mm and 12 notches at 50.4mm


16 External Notches, 39–40 mm OD

Threaded bottom bracket cup with 16 external notches, installed in bottom bracket shell on red alloy frame

16 external notches, 39–40 mm outside diameter

The Park Tool BBT-49.2 Bottom Bracket Tool

Park Tool BBT-49.2

Examples include Shimano® XTR® BB91/3/4, Dura-Ace® R9100, and Shimano® STEPS® Hollowtech® II e-bike motor lockring.

Use Park Tool BBT-49.2 or BBT-29


16 External Notches, 41–42 mm OD

Threaded bottom bracket cup with 16 external notches, installed in bottom bracket shell on gray alloy frame

16 external notches, 41–42 mm outside diameter

The Park Tool BBT-59.2 Bottom Bracket Tool

Park Tool BBT-59.2

Examples include Shimano® XT® MT800, Ultegra® BBR60/72, and others.

Use Park Tool BBT-59.2


16 External Notches, 44–45 mm OD

Threaded bottom bracket cup with 16 external notches, installed in bottom bracket shell on gray alloy frame

16 external notches, 44–45 mm outside diameter

The Park Tool BBT-69.2 Bottom Bracket Tool

Park Tool BBT-69.2

Example include Shimano® Hollowtech® II, SRAM® GXP®, Chris King® ThreadFit™ 24, Campagnolo®, Race Face®, Praxis Works®, and more.

Use Park Tool BBT-69.2, BBT-19.2, or BBT-9


16 External Notches, 48–50 mm OD

Threaded bottom bracket cup with 16 external notches, installed in bottom bracket shell on gray alloy frame

16 external notches, 48–50 mm outside diameter

The Park Tool BBT-27.2 Bottom Bracket Tool

Park Tool BBT-27.2

Examples include FSA® MegaEvo® and Wheels Mfg™.

Use Park Tool BBT-27.2 or BBT-29


16 External Notches, 52–54 mm OD

Threaded bottom bracket cup with 16 external notches, installed in bottom bracket shell on gray alloy frame

16 external notches, 52–54 mm outside diameter

The Park Tool BBT-47 Bottom Bracket Tool

Park Tool BBT-47

Examples include Chris King® and Wheels Mfg™.

Use Park Tool BBT-47
Note: This is a double-sided socket with 16 notches at 52.2mm and 12 notches at 50.4mm


20 Internal Splines, 31.5mm ID

Cartridge bottom bracket with 22 internal splines, installed in bottom bracket shell on gray alloy bike frame

20 internal splines with ISIS Drive spindle

Cartridge bottom bracket with 20 internal splines and square spindle, installed in bottom bracket shell

20 internal splines with square spindle

The Park Tool BBT-22 Bottom Bracket Tool

Park Tool BBT-22

The Park Tool BBT-32 Bottom Bracket Tool

Park Tool BBT-32

Examples include cartridge bottom brackets from Shimano® square spindle type, Shimano® Octalink®, SRAM®, Sunlite®, FSA®, Suntour®, and others.

Use Park Tool BBT-22 or BBT-32


24 External Notches, 45–47 mm OD

SRAM® DUB® bottom bracket cup with 24 external notches, installed in bottom bracket shell on gray alloy frame

SRAM® DUB® bottom bracket

The Park Tool BBT-79 Bottom Bracket Tool

Park Tool BBT-79

Examples include the SRAM® DUB® bottom bracket cup.

Use the BBT-79


36 External Notches, 51–53 mm OD

Threaded bottom bracket cup with 36 external notches, installed in bottom bracket shell on carbon fiber frame

36 external notches, 51–53 mm outside diameter

The Park Tool BBT-35 Bottom Bracket Tool

Park Tool BBT-35

Examples include Praxis Works® M35. The 36-notch cup pattern fits the 18-notch pattern of the BBT-35.

Use Park Tool BBT-35
Note: This is a double-sided socket with 12 notches at 48mm and 18 notches at 51.7mm