MiniMODs X5 Unibody Cog Set for Brompton Bicycle

MiniMODs X5 Unibody Cog Set 

Gear range: 11 / 13 / 17 / 21 / 25T

Features:

• CNC-machined unibody design: 5 cogs (11–13–17–21–25T) in one solid piece

• Made from SCM440H heat-treated steel with ED (Electrophoresis Deposition) black surface finish

• Optimized for efficient power transfer and crisp, precise shifting

• 9-spline Shimano spec: Compatible with 2/6-speed Brompton (C Line & Electric B: BWR hub) wheelsets

• Requires 3rd-party longer tensioner arm and derailleur chain pusher upgrade for proper function

• Compatible with most 3rd-party 2-speed rear hubs (e.g. MiniMODs, Hubsmith, H&H, Andoza, Joseph Kuosac, ORZ, RIDEA, Suncord) — both circlip snap ring or lock nut types

• Uses circlip type fitting for maximum compatibility — includes custom 1.5mm & 1.8mm snap rings

• Compatible with narrow 11-speed and up chains

• On-shift leading tooth design for ultra-smooth transitions

• Not compatible with Sturmey Archer SRF-5(W) or Brompton BSR 3-speed hubs

• Compatible with SRF-5(N) 10-speed (5×2), and supports 5×3 speed setups

Note:

• Older Brompton stock tensioners can only support up to 19T — a 3rd-party tensioner (e.g. aluminum models) is required

• Tested compatible with:

  • MiniMODs, H&H, BooK, DCCH, Thx4Ride parallelogram derailleur systems

  • Suncord and RIDEA chain pusher-style derailleur systems

• Additional upgrade parts required (not included):

  • 5-speed thumb shifter (Brompton stock type is ideal)

  • 11-speed or higher narrow chain

Disclaimer:

• The X5 Unibody Cog Set is based on our popular X4 Unibody Cog Set, which allows easy 2-speed to 3-speed DIY upgrades using mostly stock parts

• However, 5-speed conversion requires additional 3rd-party upgrade components and careful setup

• Not recommended for beginners — due to the tight tolerance needed on Brompton rear triangles (which may vary due to manual frame production)

• Fine-tuning may be required depending on frame and component combination