E.1.6.1. Brompton - torque lever
Brompton uses a very thin walled bottom bracket shell on their folding bikes. For mountain-drive, we offer a special anti-twisting bracket to hold the reaction torque.
You can either use cone rings (and chamfer the bottom bracket shell) for perfect centering or use a 90° nut on the left side. In this case, you don't have to modify the frame at all. Please indicate, which manner you prefer, when ordering.
For speed- and high-speed-drive, such an anti-twisting bracket isn't necessary. The standard installation with cone rings works fine here.