ms6073 wrote:Alexandrumarian wrote:I will soon receive a new PF86 frame and install Campy cups.
While in the past I have advocated for Loctite 609 for PF30/PF86 applications, that was based on bottom bracket shells with alloy inserts. Based on my experience with my 2016 Scott Solace Disc, which has an all carbon bottom bracket shell, I am going to suggest you seriously consider not using any form of Loctite unless absolutely necessary! This past weekend, in order to replace hydraulic brake hose required for DA ST-9170 shifters install, I had to remove a KCNC alloy PF86 assembly which was previously installed used Loctite 609. to To remove the bottom bracket assembly, I first tried my Enduro BRT-003 tool which typically makes easy work of the removal task. Due to the retaining compound, the tool simply pulled the bearings, and so was completely ineffective at removing the cups, so I had to resort to using a Park BBT-90.3 tool and a large hammer to force one side out then the other!
Impact, with the proper tools, is the best way to "break the bond". You can use heat, but you risk softening the resins in the carbon and/or ruining the paint. A proper tool with a good whack is the best way to go about this. I know, it seems a bit barbaric, but it's the least damaging (unless you miss and bash your frame directly instead). The "pullers", will just want to tear away at the carbon fibers gradually, or in the case above, pull out the bearings from the cups themselves. Think about it... the bond is between the outer surface of the cups and the carbon shell and that is the bond you want to break, not the bond between the bearings and the cups.
For sure if you can get away with no Loctite, and the tolerances of the pressfit shell are very good, that is the optimal way to go, but in practice that is very rarely the case. I did not use Loctite with my C60 Threadfit system, but the tolerances are so good that it wasn't necessary. And so far, so good. But that is not the system most PF30 BB's use. Instead, they are carbon shells of varying intolerances, and thus using a retaining compound from the get go is your best insurance against a creak free system down the road.