The Monkey Lab: Black Sheep Highlight ST with Schlumpf, Belt Drive, & Rohloff SPEEDHUB

We built this bike for a customer in Vail, CO who was looking for an all-around mountain bike that catered to some very specific setup needs. He enjoys long rides exploring the backcountry roads of Colorado's High Country and wanted a bike that would take his adventures further into the seemingly endless trails of the Rocky Mountains. His build needed to be reliable, low maintenance, and capable enough for all-day rides combining dirt and pavement.

For this build, comfort was a top priority for our customer given distress caused by arthritis in his hands. With this in mind, he wanted a simple ergonomic setup that would be easy on his wrists and that avoided trigger-style shifters.

To minimize bumps on rougher trails, we started with a custom titanium Black Sheep Highlight ST soft tail 29er frame designed around a 100mm suspension fork. We discussed geometry with our customer and chose angles and features that would make the bike responsive on the road yet still stable on trails. The goal was to make the bike comfortable for all-day rides, knowing that Colorado trails can quickly turn technical and challenging.

As a former professional road racer who has spent decades riding in an aggressive road position, our customer sought to replicate that body position on a mountain setup without compromising on handling. For this purpose, the frame was designed with a fairly short headtube to keep the handlebars lower and a longer top tube to keep him stretched out. A neutral headtube angle was selected for predictable steering with his long rides in mind. The result was a very aggressive racing-type position with a fair amount of handlebar drop. After we delivered the bike, our customer also added a dropper seatpost to put his center of gravity into a more neutral position for descending on trails.

The frame has a number of interesting and innovative features that set it apart. As a soft-tail, the Highlight ST does not have a fully pivoting suspension linkage but instead takes advantage of the flexibility of titanium on a more traditional tube linkage. A flexible titanium plate connects the bottom bracket to the chain stays and flexes to allow the rear wheel to move, much like the main swingarm pivot on a standard full suspension frame. A rocker link with bushings drives the Rock Shox Monarch rear shock to give the frame about 90mm of travel and keep the rear end stiff. Flex between the seat stays and chain stays eliminates the need for a separate pivot near the dropout.

The frame also has a unique chain/belt tension method designed by Black Sheep. Instead of horizontal dropouts, adjustable vertical dropouts, or an eccentric bottom bracket, the frame features telescoping chain stays that adjust to tension the chain/belt and then lock into place with a set screw. This feature fits seamlessly with the plate at the bottom bracket for a clean look. An added benefit to this is that the back end can be removed to fit into an S&S travel case to avoid the bicycle fee that most airlines charge.

Other frame highlights include internal cable routing for the Rohloff cables and stealth dropper post, three water bottle mounts for longer rides, and Black Sheep's signature curved tubing.

Our customer needed a drivetrain that would be reliable and low maintenance with a huge gear range for his all-day grinds over variable terrain. With these criteria in mind we equipped the bike with a Rohloff SPEEDHUB 500/14, Gates Carbon Drive belt drive, and a Schlumpf Speed Drive. The SPEEDHUB alone gives the bike a 526 percent gear range – the same as a normal three by nine mountain bike derailleur system – but adding the Schlumpf Speed Drive gives the bike an incredible total gear range of 868 percent. That range is enough to get up and over any trail while still being able to pedal hard on the way back down. All three of these drivetrain components are practically maintenance-free, with the SPEEDHUB typically needing no service other than an annual oil change and the belt drive lasting at least twice as long as a chain. One of our longest-running belt drive customers reported back with over 20,000 miles of commuting and touring (both on- and off-road) on a single belt.

For a sturdy set of wheels, we laced up a pair of Stan's NoTubes Flow rims to a Hope Pro II EVO hub in the front and the Rohloff SPEEDHUB in the rear. We used Sapim's bladed CX Ray spokes for light weight and aerodynamics as well as brass nipples to resist corrosion and cracking. Once the wheels were built, we mounted Continental X King tires in the 29x2.4" size, which have an intermediate knob size for cross country style riding.

To ensure hand comfort we used a Jeff Jones' titanium H-Bar, which offers multiple hand positions and generous backsweep for a natural hand position. We had sent the bar out to the customer while the frame was being built to verify that the shape would work for him, and he found the bars offered a noticeable improvement in comfort relative to a traditional mountain bike handlebar. We also installed cushy ESI "Extra Chunky" foam grips, and the rest of the bars will get taped with thick road bar tape once the customer finalizes the position of the controls.

Trigger shifters had been problematic for our customer's wrists in the past, but the standard Rohloff twist shifter solved those problems. By positioning it at the end of the bar and flipping the normal shifter orientation, he is able to shift with the heel of his hand instead of relying on his thumb and index finger, which have lost much of their grip strength.

Rounding out the build we used a selection of components that added to the durability of the bike. A Rock Shox Reba fork provides 100mm of suspension to take the edge out of harsh trails without requiring constant maintenance, Magura's MT2 brakes handle braking duties, Thomson's aluminum X4 stem provides strength and stiffness, and Shimano XTR SPD pedals offer long-lasting, quality bearings.

When our customer got his bike, he was beyond excited for a summer full of long tours through the Rockies on his new Black Sheep. If you're looking for a comfortable and capable Rohloff-equipped mountain bike of your own, contact us to start talking about what we can put together for you!

Build Details