The Eerder QR replacement handle is compatible with the original Brompton seatpost QR used on the main frame and the telescopic seatpost. When the Brompton QR is overtightened with the 10 mm nut on the right side (because your seatpost keeps sliding down), the plastic lever might slip 60 degrees on the steel hex if you put a lot of force on the lever to close it. If that happens the timing of the excentric spanner mechanism isn't right anymore and the plastic won't probably hold firm on the hex if you would force it back into position. So I figured let's design a virtual indestructable version made of laser cut stainless steel
Assembly:
See photos for instructions. The QR axle can be hammered out of the plastic handle using a thin punch which should fit inside the bore, a thick nail might work, but not ideal. Once the axle is hammered out you can degrease and clean the parts. Put them back together again with some bearing grease. Add the three supplied washers to the axle. Now flare the end with a tapered punch so the washers are fixed. Flaring the end too much might cause the axle to not rotate freely, too little and you can loose the washers. Put the steel lever onto the Brompton QR hex part, make sure it's aligned with the tiny bump in to the groove of the hex, also align it height wise. Tighten the grub screw carefully, not too tight (it's just a tiny screw) and use a good quality 1.5 mm allen key.
Specs: