Bike Forums - Bottom bracket stiffens up when installed

Hi,

I'm trying to install a used bottom bracket in an old frame. The bottom bracket is RPM BB-7420 (cartridge bearings, flange on drive side and a removable ring on non-drive side) and the frame is a POS steel MTB frame from the '90s.

I started by installing the flanged side (drive side) and it was quite difficult to thread, but before the bottom bracket was fully installed (still a gap between flange and bottom bracket housing) the bearing got stiff. The removable ring (non-drive side) was not yet installed.

What might be the cause? Bottom bracket shot? Not fitting? Bottom bracket housing destroyed?