The Monkey Lab: Schlumpf-Equipped Masuelli Bamboo/Carbon Six Speed Fixed Gear Bicycle

Masuelli Bamboo/Carbon profile view

This carbon fiber and bamboo frame was built by local Bay Area frame builder Masuelli Bikes. Neil wanted a bamboo bike partially as a novelty and partially based on the overwhelmingly positive feedback received from customers riding on the material. He had also been looking for a platform to try out the Sturmey Archer S3X 3-speed fixed gear hub and this seemed like a perfect fit.

Sturmey Archer S3X fixed gear hub and rear triangle construction

The goal was to build a fixed gear road bike for longer-distance rides. Masuelli was chosen as a more affordable option compared to other brands and was also promoting frames that were built in the Bay Area using locally grown "tubes".

Sturmey Archer three speed thumb shifter

Schlumpf Speed Drive

A Schlumpf Speed Drive was installed in the bottom bracket to increase the gear range of the Sturmey Archer S3X rear hub. The Speed Drive unit offers two front gear choices in addition to the three gears offered by the rear hub for a total of 6 sequential gear ratios, all fixed. However, since the third and fourth gears only differ by 3%, there are effectively 5 unique gears available. The overall gear range works out to 264% with 160% range from the rear hub and 165% range from the Schlumpf drive.

The first three speed fixed gear hub since the ASC model of the 1950s

Compared to Neil's first fixie, a 2-speed Brooklyn Machine Works, the extra gear range on this one makes the bike much more practical/more comfortable for longer rides through the East Bay hills. As built, the low gear allows for extended climbs on moderate grades and the high gear offers a comfortable cadence for riding downhill at decent speeds, but a slightly smaller chainring would provide an easier climbing gear without compromising descents. Gear changes on the Sturmey Archer S3X hub are clunky but generally get the job done. First gear is direct drive with gears two and three getting easier. The hub has a noticeable amount of additional drag compared to the highly efficient Rohloff SPEEDHUB 500/14 hubs that we are used to riding, but is probably acceptable for more casual use. It should not be considered a high-performance hub, but this is to be expected based on the low-cost of the unit. Unfortunately, there are no other multi-speed fixed gear hubs available that we are aware of.

Bamboo cable housing stops show thoughtful attention to detail

The frame has proven to be quite comfortable as expected. The bamboo tubes do a nice job of absorbing bumps along the road and the handling is solid and predictable. Bamboo tubes are wrapped in carbon fiber at the joints and thin steel tubes are installed to house the headset, seatpost, and bottom bracket with steel plate dropouts carbon-wrapped to the seat and chain stays.

Symmetrical chainstay bamboo nodes

This frame was made several years ago when Masuelli were just starting off and only offering brakeless fixies and coaster brake cruisers, but they were willing to accommodate some special requests into the frame for a very modest upchage. Requests for a rear brake mount, rear brake and rear hub shift cable routing, and water bottle mounts were nicely incorporated. A seat stay bridge was installed to mount the brake to, little hollowed out bamboo tubes were attached to the main frame tubes to serve as cable housing stops, and carbon bands were wrapped around the seat tube and down tube to reinforce holes for water bottle cage bolts.

Beautiful seat cluster wrapping

The fit and finish of the frame is good but not quite on par with the more established (and significantly more expensive) options available. However, given the time that has passed since we ordered this frame, the finishing details have likely improved as they have refined their process. Overall, the frame offers a good value in a hand made bamboo frame and we'd happily purchase another one.

Build details: