Carrier block adapter for brompton saddle with cateye mount

thingiverse

This is a brompton carrier block adapter for brompton seat with cateye mount. As the cateye screw mount is not very strong so an extra mounting point is required. I drilled a 5mm hole at the top of the seat post and a long thread rod was used to mount this adapter and seat post together. I used cable ties via the square holes for strapping the adapter to the seat rail in case of mount failure. It is not straight forward but an easy DIY work. It would be useful for people who got an electric brompton which lost the carrier block option. Before you go ahead, use it as your own risk. Personally I tested it for more than 200 miles with no issue. Materials required (Please read carefully til the end before start) M5 thread rod 200mm (need to cut to the right length depends on your seat position) M5 Hexagon Connecting Nuts (mine is 25mm in length you could use multiple M5 nuts instead) M5 lock nuts M5 Spring washers and ring washers M5 12mm socket cap nut M5 50mm Socket cap nut Tools M5 drill bit (Use a normal drill is fine but a press drill would be better) Ruler Instruction: 1. From the top of the seat post, measure 7mm down and Mark a dot 2. Drill through the mark across the seat post so you will have two holes on both sides 3. Mount the adapter using a spring washer and M5 12mm using an Allen key at the end of the saddle. 4. Mount the brompton carrier adapter using a M5 50mm socket cap nut. Mount only the top screw hole of the mount 5. Put the saddle back on the seat post. 6. Put the M5 thread rod across the bottom screw hole and the seat post hole. Measure the length and cut it in the right length so both lock nuts could be screwed on for both sides. Alternatively you could put everything together and cut it after. 7. Please refer to the photos about the mounting. Basically you have to fill the gap between the seat post and the mount adapter using connection nuts and M5 nuts. This helps to stop shaking and support the weight of the mounted bag using the seat post rather than the saddle mount. Starting from the front, the sequence is M5 lock nut > spring washer > ring washer > seat post > M5 connecting nut/M5 nut(s) >M5 lock nut>ring washer > mount adapter > brompton carrier block > ring washer > spring washer> M5 lock nut. 8. Use zip ties to secure the mount adapter with the seat rail in case of the saddle mount failure.