Brompton P Line: Hinge Springs and Protective Plates

Back to the annoying problem of the Brompton hinge clamps. On my previous Brompton M6R, the hinge clamps were upgraded to the Imperium Cycle type, where it works much better than the stock design. With the better design, the hinge clamps will always be aligned with the hinge even when you loosen it, avoiding the need to realign the clamps when tightening.

On the Brompton P Line, the hinge clamps have aluminium levers which are already nice. However, the hinge clamps still have the same problem of misalignment after loosening. This is unlike other folding bikes such as the Dahon, where the hinge clamps on the frame or handlepost are always aligned.

When the stock hinge clamps are loosened, they will not be aligned with the hinges any more. This requires realignment when tightening the clamps which is a bit more troublesome.

I have seen a very simple solution to this problem, which involves adding a little part to maintain the clamp's alignment even when loosened. I decided to give this a try since it is not expensive and also easy to install.

3D printed hinge springs! Made using a flexible material to provide a spring effect and also prevent cracking when compressed.

Super lightweight at just 2 grams.

Nice little innovation and note from the designers.

This hinge spring goes over the original bolt of the hinge clamps. The two "wings" keep the hinge clamp in the correct alignment even when they are no longer contacting the frame.

When the hinge clamps are tightened, the "wings" will bend and tuck itself away without causing any interference.

You can see the slim "wing" of the hinge springs hiding in the empty space under the hinge clamps. It does not take up additional space, nor affect the normal clamping function or force.

The squarish profile of the hinge springs ensure that it does not rotate when the hinge lever and bolt rotates.

I also came across a few small items to protect common contact points on the Brompton frame, and decided to try them out.

This little plate attaches to the left side of the front fork, preventing the front brake cable from rubbing against the paint.

Weighs 6 grams.

Another protective plate attaches to the underside of the bottom bracket, preventing the rear tire from rubbing against the frame when folded.

This plate is pasted onto the Brompton frame with double sided tape.

I like the ingenious design of the 3D printed hinge springs, which are so simple and yet so effective. Completely solves the hinge clamp misalignment issue without any compromises at all.