BrommiePlus Derailleur 3 Speed 10T Kit
Introduction Video (YouTube
Widest gear range available for a 3 speed kit*
– available in 10-14-17T or 10-14-18T. This represents a gear range of up to 180%, which is much wider than the stock gear range of 133%, and is as wide as the standard ratio 3 speed gear hub (178%) without the added weight and friction.
Utilizing the stock (post-2017) derailleur shifter
– with our proprietary internal modification parts, the stock 2 speed derailleur shifter is converted into 3 speed. The shifter is indexed, and capable of downshifting and upshifting one gear per stroke, It can also downshift two gears per stroke when pushing the lever all the way, which is useful when coming to a stop at the light. There is no need to buy alternative shifters that are often inferior to the purposely designed shifter, in terms of correct cable pulls, shifting performance, mounting positions, cable angle, and the overall ergonomics.
The kit is simple, comprised of 4 main components:
the 3 speed freehub body/hub driver, the sprocket set, the shifter modification parts, and the chain.
Other ancillary parts such as hub end caps, sprocket adaptor, spacers, are also included. Other factory parts such as chain pusher, actuator springs, chain tensioner do not need to be replaced.
The kit components are designed to work together and are easy to install, without the need for extensive or frequent tuning. The components are made from quality materials that are durable, and also available separately as spare/replacement.
While not absolutely necessary, when using the 10T cog set, we highly recommend reducing the front chainring size, from 54T to 50T or 44T. This will made both the climbing gear and high speed gear both more usable.
- Free hub body, including bearing, pawls, and pawl spring.
- Sprocket set, 10-14-17T, or 10-14-18T
- Chain with quick links
- Shifter modification parts
- Shifter logo button
- Gear cable
- Hub end caps
- Sprocket adapter
- Sprocket lock ring
- Lock ring tool
- Sprocket spacers
- Axle spacers (for fine adjustment, not always needed)
- Installation instruction & tuning guides
For Hubsmith rear hub owners who already has the 3 speed free hub, Please visit a separate page
10-14-17T or 10-14-18T. While almost all Brompton bikes can fit 17T, only some can fit 18T for the largest cog. To be safe, please choose 17T version. Both 17T and 18T sprockets can be purchased separately.
Sprocket sets are available in Silver or Black. The black chrome/coating will eventually wear out to expose the metal beneath.
12 speed chain are available in Silver, Gold, or Black
Axle extension nuts:
For some Hubsmith rear hub with shorter axle, extension nuts are necessary. Please see separate page
Here are a few notes regarding this kit:
- The free hub body and end caps that come with this kit will change the center line of the rear wheel, such that the wheel needs to be re-dished. While this can be done in DIY fashion using merely a spoke wrench and the rear frame as a crude truing stand, you may wish to enlist the help of a local bike shop.
- Due to the smaller diameter of the 10T cog, the protrusion in the back of tensioner back plate will interfere with the chain path, and needs to be removed. This can be done quite easy with a hack saw, or a file with some persistence. We can also supply new Brompton derailleur tensioner already modified. Please see separate page here.
- Some aftermarket brake lever that claims to be compatible with post 2017 integrated shifter, do not have precise mounting holes. Mounting the factory shifter on these levers will cause a minor distortion to the shifter, jeopardizing the smoothness of shifter operation.
- For riders who already owns the lock ring style Hubsmith free hub, it is quite possible that the existing free hub may continue to be used for the 10T sprocket set. In most cases, the blank shoulder section at the end of the splines needs to be removed (See photo). We recommend that this be done professionally by a machine shop. When in doubt, please contact us. We can also assist in machining, if machining service is not available to you locally.
- For owner of pre-2017 bikes who wish to upgrade to post 2017 derailleur shifter already converted into 3 speed, we have limited quantities in both black and silver. Please check here.
- For pre-2017 bikes, we recommend upgrading to Brompton stock post-2017 spring set, or the connection kit we offer, here, instead of using barrel nut at the end of the actuator spring. When such barrel nut is used, the cable buffering function of Brompton original design is lost, and there is a risk that the gear cable can break loose when attempting to shift while the bike is stationary.