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Count Splines/Notches
Remove the crank and inspect the bottom bracket shell for tool fittings, which 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.
Measure Diameter
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. Take the measurement in millimeters.
Select Tool
The BBT-27.3 is for 16-notch tool fittings with an outer diameter of 48–50 mm. Here are some tools we offer for this and a few similar tool fittings:
TRUSTED SINCE 1963
Since our origins in the back of a bike shop in 1963, it has been Park Tool's sole mission to design and manufacture high-quality tools that empower mechanics and riders of all skill levels to service their bicycles. Just like our other 500+ tools, our bottom bracket tools are a product of our decades of experience and expertise in the industry, in the shop and on the trail.
Michael
Reviewed in the United States on April 20, 2025
It worked on a wheels manufacturing bb30. Needed it since there’s no standard for bbs anymore, added to my collection of rarely used tools
bkirkwd
Reviewed in the United States on November 20, 2024
works without a hitch in removing the bottom bracket
Old crank
Reviewed in the United States on October 30, 2024
The tool's splines properly and securely engage the notches in the threaded BSA BB. It allows removal and installation without marring the BB. Various threaded BSA BBs have different diameters and numbers of notches, so check to make sure you get the right tool for the job.
Robert Bunnell
Reviewed in the United States on October 25, 2024
Excellent BB tools (as expected) from Park. I own tons of bike tools and I only purchase these or the offerings from Wheels MFG. I like that Park color codes their BB tools though.
Cesar Orozco
Reviewed in the United States on September 6, 2023
Scuffed out after first use
Kee Soon Yeap
Reviewed in the United States on February 12, 2023
overall is ok, still can use on Shimano group
James McMillan
Reviewed in the United States on April 17, 2023
I have a bottom bracket where the ONLY way to tighten and untighten due to the width of the external BB being less than a millimeter is using two of these tools. One on each side and a friend to help turn while I hold the two tools on with a fair amount of pressure. The good news is that I don't have to take my bike to the shop for BB adjustments anymore. The bad news is that I had to purchase two of these tools. I had previously tried (unsuccessfully) to use this tool along with the flat handled counterpart tools. My bottom bracket is Wheels Manufacturing PF30-THD. These tools when paired up like I described above do a surprisingly good job given the extremely thin BB material to work with.
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