Uploaded October 2025 | Updated September 2026, 2 weeks ago
This is one cheap, quick and easy method to fix a bike frame whose Bottom Bracket has been worn down by the rotation of the bearing housing. We discuss the various options available to fix the oversized and ovalised hole, and our process for understanding the problem and choosing a solution in collaboration with the customer.
This video case study is a Cannondale SuperSix with an PF30a Bottom bracket where the shell width is 73mm and asymmetric to the frame.
We chose to use an half an Oversized PF46 to 30mm bottom bracket from @BikoneBottomBrackets that measures 46.10mm matched with a regular 46.00 half from a donor unit. We then used the @wheelsmanufacturing3186 BBright adaptor kit to make up the required spacing for the Cannondale Ai PF30a frame. We choose to use a Loctite Bearing Retaining Compound called 638 that is more than capable of filling the maximum mesaured gap of 0.17mm in order to create a solid hold of the bearings from what would otherwise be a loose or slip fit.
Read more about Loctite retaining compounds here: henkel-adhesives.com/hu/en/products/industrial-adhesives/retaining-compounds.html
Bikone Oversized BB units here: mapdec.com/products/bikone-evo-oversized
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Chapters:
00:00 The Problem
01:38 Measuring tools
02:35 Possible Solutions
06:28 Retaining Compounds
11:10 The Repair
12:08 Crank Install
15:25 The Result
This is one cheap, quick and easy method to fix a bike frame whose Bottom Bracket has been worn down by the rotation of the bearing housing. We discuss the various options available to fix the oversized and ovalised hole, and our process for understanding the problem and choosing a solution in collaboration with the customer.
This video case study is a Cannondale SuperSix with an PF30a Bottom bracket where the shell width is 73mm and asymmetric to the frame.
We chose to use an half an Oversized PF46 to 30mm bottom bracket from @BikoneBottomBrackets that measures 46.10mm matched with a regular 46.00 half from a donor unit. We then used the @wheelsmanufacturing3186 BBright adaptor kit to make up the required spacing for the Cannondale Ai PF30a frame. We choose to use a Loctite Bearing Retaining Compound called 638 that is more than capable of filling the maximum mesaured gap of 0.17mm in order to create a solid hold of the bearings from what would otherwise be a loose or slip fit.
Read more about Loctite retaining compounds here: henkel-adhesives.com/hu/en/products/industrial-adhesives/retaining-compounds.html
Bikone Oversized BB units here: mapdec.com/products/bikone-evo-oversized
---------------
Chapters:
00:00 The Problem
01:38 Measuring tools
02:35 Possible Solutions
06:28 Retaining Compounds
11:10 The Repair
12:08 Crank Install
15:25 The Result
