(a.) X2 + 1 Combo Set : CNC machined 2 cogs (11-16T) in One Unibody + Large Cog (18 or 19 or 21T) + 1.2mm Circlip snap ring + 1mm Spacer (MiniMODs)
Important note :
Some (not all) steel rear frame Brompton can take the biggest cog up to 18t (and most Ti rear frame up to 17T), so cog larger than that with stock circlip snap ring hub will require work on the rear frame right end. (Our X3 Unibody Cog Set :11/14/17T has the non-intrusive compatibilty to frame spec, please consider X3 if you are not a hard core modder)
Stock 2/6 speed tensioner can only take cog up to 19t, anything larger you will need 3rd party custom ones.
We are working on 4 speed free hub body and accessories for 4 or even 5 speed upgrade, estimation of delivery in December 2020.
We will supply 1.2 mm circlip as default (stock hub compatible), let us know if you want other size.
(b.) 3 speed thumb shifter Left or Right (SunRace or Sturmey Archer)
(d.) Extra Cog for 4 speed or beyond application (SunRace)
(e.) Misc parts for custom build (more can be found here)
1. Older stock tensioner might suffer from deformation and cause it to touching chain on 11t position (you will need some filing or add tensioner washer to correct). Aluminum 3rd party tensioners are stiff enough to void this. 11 speed chain also helps with its narrower profile.
(a.) X2+1 Unibody Cog (MiniMODs)
2 cogs (11-16T) 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. Most Stock components compatible
Prefer 11 Spped and up Chain. Leading teeth on-shift design for ultra smoothness.
Circlip type for maximun compatiblity (1.2 mm custom snap ring included).
For 9 spline Shmano 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