POSST Object use T47 bottom bracket shell.
The T47 bottom bracket shell has an enlarged diameter with M47x1 thread. Combined with over-sized tubes, the unit forms a stiffer joint, resulting in more efficient energy transfer when pedaling with the benefit and peace of mind of a threaded system..
An oversized bottom bracket shell means a larger area for the down tube and seat stays to be welded onto. From a frame builders perspective, this makes a lot of sense. T47 is now fast becoming the standard on high end and premium handmade steel bikes from Europe.
We use T47 bb cups which are CNC machined from a solid billet of aircraft grade aluminium by Rideworks of UK, to accommodate our Campagnolo's Ultra Torque crankset.