top of page

Brompton Non-Chamfer BB Mountain Drive Gearing System (ATS) Made in Taiwan

In stock
Product Details
Item location: Taiwan
Status: In stock
Payment: Paypal, Credit Card
Ship to:: Worldwide (REGISTERED AIRMAIL)

An Ultra wide range gearing system to maximize your Brommie performance. (No BB shell chamfering required)

Brompton as one of the best folding bike design has always suffered the lack of proper gear range for hilly terrains. BIKEgang has kept searching for the best gearing solution for quite some time. Mountain Drive is always our top choice to widen the gear range.

Mountain drive is a gearing system that makes the chainring spinning at a much lower rate (2.5:1). For instance, 56T chainring with mountain-drive engaged, will work like a much smaller one (23 tooth chainring equivalent).

This Brompton version comes with a torque arm to prevent BB shell preparation. So no BB shell preparation required.


(Chain driven version / Model SD040)

- Cone ring configuration, incl. gears, crankarms, kickplates, 56T or less Chainring and chain guard (or 60T chainring without cover) - BCD110 spec.

- With two gears: Direct drive 1:1, Underdrive 2.5:1

(1:0.4 = 60t: 24t gear ratio. That is if you install 60t physical chainring. Heel kick will gear shift to 24t when engaged.)

- BB and Axle included for Brompton spec. Contact us for other bike or ebike custom model.

Weight:About 1700 g.

Please compare the total weight of mountain-drive to the total weight of a triple

chainring set including shifter, cable, derailleur. Example: Shimano Altus

(48/38/28 teeth): weight incl. right crankarm: 1255g

ATS speed drive will not be shipping to US or EU address, please be noted!


  1. Planetary gearing system with two switch positions: direct drive 1:1, underdrive 2.5:1
  2. Direct shifting via push buttons or "easy-shift" - levers on both ends of the spindle. No cables, no rods.
  3. Gear housing : Corrosion resistant, completely encased and protected against dust and spray water.
  4. Axle: Rides on (replaceable) cartridge bearings. You can expect a lifetime of more than 20'000 miles for the bearings and much more for the mountain-drive.
  5. No chamfering on BB shell required.

!!!Special Note !!!

This MOD is not for casual rider, special tools are needed to perform this modification (BB and crank set removal and installation), unless you are an experienced technician, please consult local bikeshop for help.

We are glad to provide all info and manual to help you go through the processes.

Schlumpf Mountain Drive will ship to the world with EMS express service 1 week delivery typical.

About ATS

ATS, Fujiss Corp. is committed to giving consumer the ultimate quality and advance in transmission system parts. We focus on consumer's needs and satisfaction as the core of our company creed.

The ATS-Speed drive is manufacturing under license of Haberstock Mobility GmbH. We make this excellent bike gearing system in efficient production and inexpensive. We would like to let consumer have another choice to make their own bike more simple, clean (no shifting cable), easy riding or even enhance function of bike .

Save this product for later
bottom of page