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?
  • Digital caliper, such as Park Tool DC-1

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.

Bb Press Tool Article Dub

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.

Bb Article Splinecount

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, simply measure the outer diameter of the bottom bracket cup or adapter as seen below.

Bb Article Measureextcup

Measure the outside diameter

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.

Bb Article MeasureID

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 between the bike and the tool examples. There are also some proprietary brands not listed here.

Tool Fitting Dimension Tool
2 flats 16mm widthHCW-11
2 flats 36mm width HCW-4
4/6/8 pin holes 3mm hole SPA-1
3/4/6/8 external notches 44–46mm OD HCW-5
6 external notches 43mm OD BBT-4
8 external notches 40–45mm OD BBT-18
12 internal splines 23mm ID BBT-5/FR-11
12 external notches 46mm OD BBT-79
12 external notches 48mm OD BBT-35
12 external notches 50.4mm OD BBT-47
16 external notches 39mm OD BBT-49.2
16 external notches
41mm OD BBT-59.2
16 external notches 44mm OD BBT-69.2
16 external notches 49mm OD BBT-27.2
16 external notches 52.5mm OD BBT-47
20 internal splines 31.5mm ID BBT-22, BBT-32
24 external notches 46mm OD BBT-79
36 external notches 51.7mm ODBBT-35
3

Tool Fittings

2 Flats, 16mm Width

Bb Article Round 2 2 Flatsbb

2 flats on adjustable cup

Bb Tool Hcw 11

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, 36mm Width

Bb Tool Hcw4

Bottom bracket cup with two wrench flats

Bb Tool Hcw 4

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

Bb Tool Bbtspa 1

Pin holes in left cup

Bb Tool Spa 1

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, 44–46mm OD

Bb Tools Lockring Hcw5

External lockring of adjustable cup bottom bracket

Bb Tool Hcw 5

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, 43mm OD

Bb Tools Bbt 4

6-notch cartridge bottom bracket

Bb Tool Bbt 4

Park Tool BBT-4

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

Use Park Tool BBT-4


8 External Notches, 40–45mm OD

Bb Tool Bbt8

8 external notches

Bb Tool Bbt 18

Park Tool BBT-18

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

Use Park Tool BBT-18


12 Internal Splines, 23mm ID

Bb Article Round 2 3 074

12 internal splines

Bb Tool Bbt 5 Fr 11

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, 46mm OD

Bb Tools Bbt 79

12 external notches, 46mm outside diameter

Bb Tool Bbt 79

Park Tool BBT-79

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

Use Park Tool BBT-79


12 External Notches, 48mm OD

Bb Tool Selection Bbt 35A

12 external notches, 48mm outside diameter

Bb Tool Bbt 35 002

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, 50.4mm OD

Bb Tool Selection Bbt 47A

12 external notches, 50.4mm outside diameter

Bb Tool Bbt 47 002

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, 39mm OD

Bb Tools Bbt 49

16 external notches, 39mm outside diameter

Bb Tool Bbt 49

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, 41mm OD

Bb Tool Bbt 59

16 external notches, 41mm outside diameter

Bb Tool Bbt 59 2

Park Tool BBT-59.2

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

Use Park Tool BBT-59.2


16 External Notches, 44mm OD

Bb Tool Bbt 69

16 external notches, 41mm outside diameter

Bb Tool Bbt 69 2

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, 49mm OD

Bb Tool Bbt 27

16 external notches, 49mm outside diameter

Bb Tool Bbt 27 2

Park Tool BBT-27.2

Examples include FSA® MegaEvo® and Wheels Mfg™.

Use Park Tool BBT-27.2 or BBT-29


16 External Notches, 52.5mm OD

Bb Tool Selection Bbt47B

16 external notches, 52.5mm outside diameter

Bb Tool Bbt 47 001

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

Bb Tool Bbt 22 Isis

20 internal splines with ISIS Drive spindle

Bb Tool Bbt 22 Square

20 internal splines with square spindle

Bb Tool Bbt 22

Park Tool BBT-22

Bb Tool Bbt 32

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, 46mm OD

Bb Tool Bbt 79 Dub

SRAM® DUB® bottom bracket

Bb Tool Bbt 79

Park Tool BBT-79

Examples include the SRAM® DUB® bottom bracket cup. This is the same pattern and size as cups with 12 notches and 44mm OD.

Use the BBT-79


36 External Notches, 51.7mm OD

Bb Tool Selection Bbt35B

36 external notches, 51.7mm outside diameter

Bb Tool Bbt 35 001

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