4 Speed Rear Hub for CLine Brompton with Ceramic Bearing 28 Holes (MiniMODs)

X4Ceramic Combo Note: 1. 4 speed upgrade will require more skill and patience than the 3 speed upgrade, which is most stock parts compatible. 2. For 4 speed upgrade, you will need improved tensioner and jocky wheel (for over 19t cog, some can take up to 27t). Longer travel chain pusher (DR spring set). We are in the process of sourcing and reviewing these 3rd party upgrade parts. 3. For now, you can just use the Combo kit as 3 speed upgrade as a start and reserve the possibility for future 4 speed upgrade project. 4. 11 speed chain is ideal for these thin profile cogs. Parts introduction and tips on external cogs upgrade project (a.) X3 Unibody Cog Set (MiniMODs) 3 sprockets (11-14-17T) in One Unit. Precision CNC machined SCM440H heat treated steel. ED-Electrophoresis deposition surface processed black Most efficient drive output, crispy clear shifting reaction Plug and play, very easy to install and finetune. Stock components compatible 11 Speed and up (narrower) Chain required. Leading teeth on-shift design for ultra smoothness. Circlip type for maximum compatibility (1.5mm custom snap ring included). For 9 spline Shimano spec, compatible with Stock Brompton 2 speed hub (BWR 3x2 6 speed hub) and most third party external cog wheel mods (e.g. MiniMODs, Orz, Hubsmith, Joseph Kuosac, etc. ) Not compatible with Sturmey Archer SRF-5 (W) 5 speed hub or Brompton BSR 3 speed, but compatible with SRF-5(N) 10 (5x2) speed hub, so 5x3 is possible (b.) 3 speed indexed thumb shifter Right handlebar version (c.) Shifting cable terminal Barrel Nut (MiniMODs) Titanium Barrel nut shifting cable terminal fixed. (d.) Extra Cog for 4 speed or beyond application (SunRace) Extra cog for even more speed expansion project (e.g 11-14-17T + 21T) as shown in the photo (require custom free hub body which is not included in this listing). Heat treated steel. ED-Electrophoresis deposition surface processed black Leading teeth chain on design, precise chain reaction Shimano 9 splines free hub body compatible. For 10 speed and up chain.