Welcome to the new and improved Proflex / K2 Tech Forum!
Not 100% certain, (but pretty sure....) that the bearings in a RK001 "9-style" kit are the same dimensions as the bearings in a RK008 kit.http://www.ebay.co.uk/itm/K2-NOLEEN-RK001-Pro-Flex-9-Style-Frame-Rebuild-Kit-NEW-/391492858914?hash=item5b26caf422:g:FDAAAOSwbYZXbw3Ui.e. the pivot bearings on a x57 are the same as a "two tube" or Carbon bike (x000 & x500 series)at worst, they may be a bit "deeper" and might need "slimming" but possibly not!Any one else?Col.