I have never really been a fan on the threadless bottom brake, it just seems that no one has made a quality one. They are also good if you have stripped out your BB threads.
Unlike previous attempts at threadless BBs, this new design is “internally expanding”. As the adjustable cup is tightened the silver sleeve (see photo) is pushed up the tapered alloy cups, expanding and locking in the BB. This differs from older designs, like the Mavic, that pressed in from the outside and would sometimes slip. Installation requires only a traditional-style BB spanner or a pin wrench. The BB shell does not require chamfering or facing, simply slip the BB into the shell and tighten.
Like the other Grand Cru BBs, these have sealed cartridge bearings so require no servicing and should have a very long life. Taper is JIS and available spindle lengths include 103mm, 107mm, 110mm, 113mm, 116mm, 122mm, 127mm. The color is as shown (sorry). Price is $60.
We have tried these on British, French, and Swiss frames and they work perfectly. I don’t know if they will work in the odd Raleigh BB shells since we don’t have frames to test them in. These BB will make it cost effective to put a lot of great old frames back on the road, especially Swiss threaded Motobecanes.
Speaking of BBs, Grand Cru Italian thread BBs, with JIS taper, will arrive in a couple of months.