The Monkey Lab: August 2012

20 August 2012

Rohloff-Equipped, Belt Driven Firefly Custom Titanium Dream Commuter

These photos of a titanium super commuter were submitted by Firefly Bicycles. This bike has all manner of bells and whistles and an amazing level of component integration. The guys at Firefly have nearly three decades of experience building top quality bike frames, but what really sets them apart is their amazing level of creativity and attention to detail. The finishes on their bikes are often understated, but striking. Small touches of color in minimalist graphics, logos, or head badges tie components color accents into the frame for an aesthetically pleasing package. Browse their gallery to see more examples of their work.

Firefly came to us for the wheels, belt drive components, and gear ratio advice. The Rohloff SPEEDHUB 500/14 had been chosen for the gearing system based on its reputation for ultimate durability. The Gates Carbon Drive Center Track belt system is a natural partner for the Rohloff SPEEDHUB 500/14 as it offers a very long lifespan and almost no maintenance. Together, you get a drivetrain that you never have to worry about, which is key when you rely on your bike for daily transportation.

Ultralight, Rohloff-Equipped Cannondale Flash Mountain Bike

These photos were submitted by one of our customers in British Columbia, Canada. His Cannondale Flash carbon fiber mountain bike weighs in at just shy of 20 pounds without pedals, making this the lightest Rohloff SPEEDHUB 500/14-equipped bike that we have worked with. The carbon frame is as light as many high-end road frames and the parts spec includes plenty of lightweight carbon bits. The Lefty fork also helps bring the total weight down.

This customer purchased a Rohloff SPEEDHUB 500/14 from us last summer for his tandem and fell in love with its shifting performance. So, when replacing his mtb this spring, a Rohloff SPEEDHUB 500/14 was his preferred drive train for the new bike. We built up the wheels and helped troubleshoot a few installation complications.

For the wheels, we laced the Rohloff rear hub and Project 321 Lefty-specific front disc hub into No Tubes Crest rims using Sapim Laser spokes and alloy nipples. This gave the customer a lightweight wheelset to complement the rest of the bike. We have long been fans of the No Tubes rims for their ease of tubeless tire setup and chose the Crest model for this build based on a light weight rider. The Crest model is billed as a general XC rim and is offered in 26", 650b/27.5", and 29" sizes. Its 24.4mm width is typical for an XC rim, but at 340g, it is lighter than just about all other aluminum rims on the market. We generally prefer to use these rims for lighter riders or race day wheels for moderate weight riders. The Laser model is a thin double butted spoke from Sapim that sheds weight without the higher cost of the bladed CX-Ray model and also makes for a more comfortable wheel.

As with many current mountain bike frames, this Cannondale Flash frame has post mounts for the rear brake instead of the traditional international standard mount. This makes our Monkey Bone (or Rohloff Speedbone) incompatible with the frame and the torque arm must be used to keep the rear axle from rotating during use. Normally when using the torque arm, the cable box gets oriented so it points upward and the cables loop up and over the brake caliper and along the left seat stay. This is done because there is interference between the cable box and the torque arm if the cable box is positioned under the dropout for our preferred cable routing along the left chainstay.

On this frame, the position of the post mounts caused interference with the cable box if it was oriented such that the cables would loop up and over the brake caliper. The only cable box orientation that cleared both the torque arm and the post mounts was to point it downwards and loop the cables under the torque arm. We ran into the same issue on this Spot Acme conversion, which also has post mounts instead of an IS mount. Functionally, this orientation shifts just fine, but it does position the cables closer to the ground as well as create a loop that could snag a branch. In the photos, the cables dangle quite far under the torque arm, but the customer has since anchored them to the torque arm with a reusable zip tie as we did with the Spot Acme mentioned above.

Chain tension is controlled by a Beer Components BB30 eccentric. These US-made eccentrics allow a frame with standard vertical dropouts and an oversized BB30 bottom bracket to be set up without a chain tensioner. The only caveat is that you have to use a crankset with a 24-mm integrated spindle, such as the Race Face Turbine; square taper or BB30 cranksets will not work. Also now available from Beer Components is a slightly larger diameter version for Press Fit30 bottom bracket shells, which are becoming the standard shell size for BB30-compatible frames.

Build details

Frame: Cannondale Flash carbon fiber

Fork: Cannondale Lefty Max Carbon XLR

Headset: Cannondale

Stem: Cannondale for Lefty

Handlebar: Ritchey WCS Carbon

Shifter: Rohloff

Grips: Ergon GP1 for Rohloff

Seatpost: Ritchey WCS Carbon

Saddle: Tioga Spyder

Front Hub: Project 321 Lefty

Rear hub: Rohloff SPEEDHUB 500/14

Spokes: Sapim Laser

Nipples: Sapim Alloy

Rims: No Tubes Crest

Tires: Schwalbe Racing Ralph

Rear Skewer: Shimano XT

Cranks: Race Face Turbine

Bottom Bracket: Race Face X-Type

Chainring: Race Face Single

Chain: Wippermann 8sX

Brakes: Avid XX

Rotors: Hope/Avid 160/160mm

02 August 2012

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.