Soma Wolverine Adventure Bike with Rohloff SPEEDHUB 500/14, Gates Carbon Drive Belt, and Schmidt Dynamo Hub

This decked-out Soma Wolverine was built for a customer in San Jose, CA. The rider was looking for a rugged commuter bike that would be efficient on his daily trips to work, but would also offer the versatility to enjoy longer tours on the weekend and even a few cycling-oriented vacations. Soma’s Wolverine frame fit the bill as a sturdy option that is affordable, works well with a Rohloff hub, and is belt-ready.

Like many of our customers, the rider was drawn to the simplicity and hassle-free nature of the Rohloff SPEEDHUB 500/14 internal gear hub and Gates Carbon Drive belt drivetrain. Shifting duties are handled by a set of Campagnolo Veloce shifters driving a Gebla Rohbox. A dynamo hub and lights from Schmidt, which are self-powered, were also high on the list of requirements for daily utilitarian use. From there, Cycle Monkey rounded out the build with a variety of high end parts to create a top quality commuter that isn’t afraid to stray off the beaten path.

Soma Fabrications, whose South San Francisco headquarters are located a stone’s throw from Cycle Monkey, offers affordable steel frames that are often considered an alternative to Surly. Price, intended use, and many features are similar, but the sliding dropouts and belt drive compatibility of certain Soma models, like the Wolverine, easily check the boxes for many of the build requests we see at Cycle Monkey.

Compared to the horizontal dropouts used by Surly, sliding vertical dropouts allow you to swap wheels more easily. The Wolverine also features a handy split in the right seatstay, which allows a belt to be installed without the frame modifications required with Surly frames.

Look closely, and you'll see a split in the right seatstay, which allows for easy installation of the Gates Carbon Drive belt. 

Soma says the original intention for the Wolverine was to build a monster cross bike—basically a drop bar bike with cyclocross geometry and cross country mountain bike wheels. The idea was to create a fully-capable off-road touring rig that would also be sporty enough for commuting through the city and all-around adventure riding.

The Wolverine is capable of running a wide variety of drivetrains, including the ultra low maintenance setup included with this build. Rohloff’s SPEEDHUB 500/14 is an internal gearing system with 14 evenly-indexed speeds entirely encased in the rear hub. In addition to the benefits of such a wide gear range, the internal nature of the gearing makes it virtually impervious to the elements, making it an ideal option for both off-road use and year-round riding. Even for daily commuters like this rider, the only service required is an annual oil change, which can be completed at home or by Cycle Monkey.

Rohloff's SPEEDHUB and the Gates Carbon Drive belt system are an easy fit with the Wolverine's sliding vertical dropouts.

Looking for the ultimate in reliability and lack of maintenance, this rider paired the Gates Carbon Drive belt system with his Rohloff hub. Belt drive systems don’t rust in inclement weather and they don’t require lubrication. Simply wipe ‘em down after a particularly dirty ride, and you’re good to go again. We also see Gates Carbon Drive belts lasting 5-10x longer than your average chain and they do not stretch—meaning you won’t have to readjust the dropouts to maintain belt tension.

Rohloff SPEEDHUBs are typically activated with a twist shifter, which can be mounted to the end of drop bars with an adapter. Many riders, like the owner of this Wolverine, prefer the feel of traditional road bike brake lever shifters (brifters) on their drop bar bikes. Gebla’s Rohbox allows you to run the SPEEDHUB in tandem with brifters from SRAM or Campagnolo, making it an easy choice for this build.

The Gebla Rohbox ratchet box pairs with modified Campagnolo or SRAM shifters, making it a great choice for drop bar riders who find the Rohloff twist shifter unappealing.

Naturally, we took full advantage of the included braze-ons for this utilitarian machine, with front and rear racks from Tubus capable of hauling the groceries as well as bikepacking gear. Front and rear lights on this build are courtesy of Schmidt, and are powered by a SON dynamo front hub. Dynamo hubs contain a small electric generator that self-powers lights and other electronics as you ride. They’re an ideal solution for commuters and bikepackers, because they keep your lights running both day and night with no need to charge.

Dynamo lights from Schmidt can be mounted at the fork crown or to the front rack, as on this Wolverine

Wolverines are known to be vicious, but we wanted to ensure the bike provided a friendly ride with all the mileage it’d be getting. High volume Schwalbe Marathon Plus tires provide a cushy ride without sacrificing efficiency, while hydraulic disc brakes provide ample stopping power with lots of modulation.

Comfort at the most important touchpoint comes thanks to an all-leather Brooks Saddle mounted to Cane Creek’s Thudbuster seatpost. As the name implies, the Thudbuster mitigates the jarring effects of rough roads by isolating the rider’s seating position from the frame with 76mm of travel right in the seatpost. Paired with a high-end saddle like those from Brooks, the Thudbuster adds a significant amount of comfort to any bike with a rigid rear end, and it might just save yours.

Isolation at its finest

With a low-maintenance, belt-driven internal drivetrain from Rohloff and Gates, an always-on lighting system from Schmidt, and ergonomic touchpoints for comfort over the long haul, this Soma Wolverine is just one example of how these versatile steel frames can be built up. They’re a perfect building block for the worry-free bike we love to put together at Cycle Monkey. Order yours today, and drop us a line so that we can bring it to life with a custom build kit perfect for the way you ride.

Frame: Soma Wolverine
Fork: Soma Wolverine
Headset: Chris King NoThreadset
Stem: Thomson X4
Bar: Salsa Cowchipper
Shifter: Campagnolo Veloce with Gebla Rohbox
Bar Tape: Lizard Skins
Seatpost: Cane Creek Thudbuster LT
Saddle: Brooks B17
Front Hub: Schmidt SON28
Rear Hub: Rohloff SPEEDHUB 500/14
Spokes: Sapim Race
Nipples: Sapim Brass
Rims: Velocity Dyad
Tires: Schwalbe Marathon Plus
Cranks: Shimano XT
Pedals: Shimano XT Trail
Bottom Bracket: Chris King
Sprockets: Gates Carbon Drive
Belt: Gates Carbon Drive
Front Light: Schmidt Edelux
Rear Light: Schmidt SON Taillight
Front Rack: Tubus Tara
Rear Rack: Tubus Logo EVO
Bottle Cages: King Cage Stainless

Soma Sandworm Fatbike with Rohloff SPEEDHUB 500/14, Gates Carbon Drive Belt, and Lauf Leaf Spring Fork

San Francisco-based Soma Fabrications recently sent us a production version of their first fat bike frame, the Sandworm. This is a great affordable option for a Rohloff- and belt-compatible fat bike. The frame is designed with several key features to run a Rohloff-Gates Carbon Drive belt drive train.

We built this Sandworm up as demo with a Lauf Carbonara leaf spring fork. Assembly was very straight forward. With only a few quick spins on it, the geometry feels very neutral and familiar.

Previously, we built up a prototype version for form, fit, and function validation. Throughout the assembly, we made notes on the ease of assembly and integration with the Rohloff-belt drive train.

The production version of the Sandworm evolved based on lessons learned from the prototype, while maintaining the earlier tube shape and geometry.

The prototype was built with a 135mm offset rear triangle, which worked with the original SPEEDHUB 500/14, while the production version made the change to 170mm symmetric spacing and accepts the SPEEDHUB XL.

Soma Rush Fixed Gear With Belt Drive

When a local customer contacted us about building a belt drive-equipped fixed gear for him, we were excited to execute his vision. He wanted a bike that would be simple, lightweight, and durable for commuting around town quickly. He gave us a few general guidelines for the build but asked us to make our own recommendations for parts that would fulfill his requirements. His primary requests were that the frame be chrome colored and that he could use a belt drive system. He planned to use the bike to zip around Oakland and commute across town to work - primarily short, fast rides without much climbing.

REVIEW: Soma Sandworm Fatbike with Rohloff SPEEDHUB and Gates Carbon Drive Belt

Soma Fabrications called us recently and told us they were designing their first fatbike frame named the Sandworm; they wanted us to test out the prototype and give it the Rohloff SPEEDHUB 500/14 internal gear hub and Gates Carbon Drive belt drive treatment that we are known for. We were glad to hear they had decided to expand into fatbikes with this frame and potentially bring the fun of fatbiking to more people by filling a hole in the market for an affordable Rohloff/belt drive frame. Once we received the frame, we began mapping out a build kit suitable for this project.

Rohloff-Equipped Soma Juice 29'er Mountain/Touring Bike

This Soma Juice 29'er was built for a customer in San Jose, CA as a multi-purpose bike.  The goal was to build a moderately priced bike around the Rohloff SPEEDHUB 500/14 that was capable of off road use, running errands, and light touring.  This type of bike represents a growing category often described as an adventure bike.  Adventure bikes are typically built around a frame with mountain bike geometry, but can go in many directions: mountain or road handlebars, rigid or suspension fork, more off road or more touring oriented features, etc.  The Rohloff SPEEDHUB 500/14 complements an adventure bike by providing a reliable, low maintenance drivetrain so the rider can spend more time riding and not have to worry much about adjusting or maintaining the bike.


The build kit focused on comfort, durability, and value.  A mid-level Rock Shox suspension fork, Cane Creek suspension seat post, and an upright riding position give the rider plenty of comfort.  The US-made Selle Anatomica Titanico saddle feels good out of the box with a thick leather cover that provides good long term wear life.  Ergon grips have a wide palm rest that reduces hot spots.  Tires were chosen with a moderate tread that could provide decent traction on unpaved surfaces while still rolling on the pavement without too much resistance.

Brakes are Magura's excellent MT2 hydraulic units.  Positioned as the entry level model in Magura's 4-tier MT lineup, the "2" model offers great performance at a price that is not much higher than a mechanical disc setup.  They are lightweight and have great stopping power and durability.  Magura offers a 5-year warranty on their brakes, which bests most if not all other manufacturers' warranties.

For the wheels, we laced the Rohloff rear hub and a Shimano XT front disc hub into Velocity Dyad rims using Sapim Laser spokes and brass nipples.  We use the Dyad rim for many applications, and in this case, it offered a good combination of weight, strength, adequate tire support, and price.  The Laser spoke is a thin double butted model that was chosen for this lighter weight rider for improved comfort over a thicker spoke.  The inexpensive Shimano XT front disc hub is a standard value-priced option.  These 6-bolt hubs use loose ball bearings and can hold up to many thousands of miles of service with some routine maintenance.

The chromoly steel Soma Juice frame was chosen as a value-oriented option that was a good match with the Rohloff SPEEDHUB 500/14.  The steel tubes provide a comfortable, durable frame and for 2012, the Juice model was updated to include sliding dropouts instead of the horizontal ones previously used.   Sliding dropouts offer an easy method for tensioning the chain as well as anchoring the Rohloff SPEEDHUB 500/14 axle to the frame when combined with our Monkey Bone brake adapter.  The only thing missing on this frame are Rohloff cable guides, but the cables are easily held in place with zip-ties.

With the update of the Juice model, Soma now offers inexpensive, Rohloff-friendly frames for the three common mountain bike wheel sizes - Analog (26"), B-Side (27.5"/650B), and Juice (29"/700c).  These are some of the few stock frames on the market that offer sliding dropouts, which is even more impressive considering their low price.  Most frames in this price range use horizontal dropouts, which are cheaper to manufacture, but have some drawbacks, especially when using disc brakes.  We much prefer adjustable dropouts or an adjustable bottom bracket to adjust chain or belt tension.

The Soma frames are a good choice for a value-oriented Rohloff bike build and a viable alternative to a Surly Troll (26") or Ogre (29"), which are also popular Rohloff frames (see example here).  The Surly frames have more features than the Soma frames - bigger tire clearance, accommodates disc or rim brakes, more mounting points for racks, fenders, and even their trailer, and multiple cable routing options - but the Soma frames have adequate features for most rider's needs and we find the installation and adjustment of the rear wheel to be much easier with the Soma frames.  Depending on your intended use, the Soma may be the better choice.  Contact us to help determine which frame will work best for you.


Build details

• Frame: Soma Juice CroMoly steel
• Fork: Rock Shox Recon Gold
• Headset: Cane Creek S3
• Stem: Soma Shotwell
• Handlebar: Salsa Bend 2
• Shifter: Rohloff
• Grips: Ergon GP1 for Rohloff
• Seatpost: Cane Creek Thudbuster LT
• Seatpost Collar: Salsa Rack-Lock
• Saddle: Selle Anatomica Titanico
• Front Hub: Shimano Deore XT
• Rear hub: Rohloff SPEEDHUB 500/14
• Spokes: Sapim Laser
• Nipples: Sapim Brass
• Rims: Velocity Dyad
• Tires: CST Critter
• Skewers: Shimano XT
• Cranks and Bottom Bracket: Shimano Deore
• Chainring: Race Face Single
• Chain: Wippermann 808
• Brakes: Magura MT2
• Rotors: Avid G2 Cleansweep 160/180mm
• Rear Brake Adapter: Cycle Monkey Monkey Bone