Brompton 3 speed and bigger cog (22T) modification on stock wheel and hub (H&H x #BIKEgang)
Video demo 12-16-22T
The original wheel set (2 speed) changed to 3 speed! Important milestone!
Some brompton pals had asked me if I could change the stock wheel set to 3 speed. I always said this mod is easier to perform on nut lock type hub wheelset. Actually, this was an lazy answer. The C clip type wheel is not easy to change, and rather hard to adjust. But since more and more people interested in this. I shall treat it as a serious project.
There were quite a few videos showing the result of 3 speed modification on stock wheel, but not many details for the processes. Some require ratchet type cogs, and some with specific designed cog set. .... With the principle of least change is the merit, I took one day to play with this project here is some results to share . Modification conditions and parts to be prepared:
Original wheel set
The original 3 speed thumb shifter
Shifter fine-tune knob (what is this??)
11 speed chain,
11 speed cogs,
1.6mm C clip
1.6mm C clip, customized item, price is OK, the original C clips is 2.2mm
Choose 1.6mm thick cogs, 11-speed tooth
The spacers in between cogs should be 2.2mm. 2.0mm spacers will be make chain reaction much louder.
Tensioner with spacer to move outward 0.5mm (Jockey wheel range?)
With more and more 3 speed modification out there, some method were improved over time. For example, the black technology of clip and clamp rear frame end is more trouble-free than filing.
By saving a brand new costy rear 3rd party wheelset, you can experience the 3 speed upgrade with more affordable cost.