Groovy Cycle Works Hot Rod Cranks in Stock!

After nearly a year of waiting, we finally received our first batch of Groovy Cycle Works Hot Rod cranks. These tubular chromoly steel cranks are hand made in Wooster, OH and weigh 712g. A 24mm diameter axle is attached to the drive side arm and the non-drive side arm is secured to the axle using two 5mm Allen-head pinch bolts. A three-lobed polygon interface is used between the non-drive arm and the axle for high torque transfer capability. The 24mm axle is compatible with external bearing bottom brackets from Chris King, Hope, Acros, Enduro, Race Face, Shimano, and others.

A precision machined spider is attached to the drive side arm using three small screws around the axle and one large bolt that anchors into the crank arm. The spider will accept a chainring or a Gates Carbon Drive belt pulley. The crank arms have a durable ceramic coating that eliminates chipping or heel-rub concerns common with other finishes.

Rody at Groovy Cycle Works makes a very limited number of these cranksets each year and we were lucky to get a small batch of them. Neil has been riding a prototype version of the cranks since 2008 and an early production pair since 2011 and has been very impressed with them. While these are not the lightest cranks on the market, they are certainly not heavy. They are ultra stiff and offer a unique addition to any bike build.

We currently have 4 pairs of Hot Rods available in 175mm length with a dark grey finish and 4-bolt, 104mm BCD spider. These are all custom made for the 54mm chainline of the Rohloff SPEEDHUB 500/14. Price is $440. Chainrings, Gates Carbon Drive belt pulleys, and external bearing bottom brackets can also be supplied. Please contact us to let us know what you need.

Schlumpf-Equipped Airnimal Chameleon Folding Bike

After struggling with a troublesome front derailleur on his Airnimal Chameleon folding bike, Bruce Metras of B. Metras Company (San Rafael, CA) upgraded his bike with the installation of a Schlumpf Speed Drive.

The Schlumpf system simplifies the drive train by using a single chain ring in the front that is connected to a two-speed internal gear system encased in the bottom bracket. Since the chain remains on a single ring, there is no possibility of an overshift occurring that would result in a dropped chain. This set-up also allows riders to access all available gears on the rear cassette, as the centered chain line eliminates cross-chaining.

The 1.65 ratio change of the Schlumpf SpeedDrive offers a direct gearing replacement for the original front derailleur and double crank set. For smaller-wheeled bikes, like the Airnimal, this option is especially useful, as it gives riders the same effective gear ratios available on standard bikes without requiring the use of extra-large chain rings. Often, the chain ring size needed to get the desired output is so large that it is not readily available and leads to shifting problems due to component size mismatch:

• Front derailleurs are shaped to work with the chainrings sizes commonly found on bikes with 26" and 700c wheels. Larger rings do not match this shape well.
• The difference in tooth count between two chain rings increases as their size grows (assuming a fixed ratio between them) and quickly exceeds the capacity of the front derailleur.
• The chain angles created by the large chain ring and shorter chain stays of a smaller-wheeled bike cause poor shifting and excess chain and sprocket wear.

With a Speed Drive, these issues are eliminated. Riders can use a single smaller ring and still get the larger gearing that is desired without any of the problems associated with using larger chain rings on small-wheeled bikes. Riders of standard bikes also benefit from the Schlumpf set-up. Check out our previous post on using a Schlumpf Speed Drive on a fixie.

Bike highlights

• Frame: Airnimal Chameleon folding bike
• Front Gearing/Front Derailleur Replacement: Schlumpf SpeedDrive Gearing System
• Crank arms: Truvativ left-side square taper arms with right-side pedal insert on one arm

Center Track Belt Parts in Stock!

Today, the Fedex man came with a box of long-awaited Center Track belt parts from Gates Carbon Drive, including pulleys for the Rohloff SPEEDHUB 500/14.

Center Track represents the next generation of the belt drive system from Gates Carbon Drive. This version brings improvements in both installation and performance. Here's an overview of the design changes.

The flange on the pulleys has been moved from the outside edge to the center, and a mating groove has been cut down the middle of the belts. This allows the belt to be fully captured by each pulley, improving both installation and operation. The system is easier to setup as there is now more tolerance for misalignment between the front and rear pulleys. Most importantly, it also reduces the chances of the belt wandering off the pulleys while riding.

The mounting surface for the pulleys has also been moved to allow for adjusting the alignment between the front and rear pulleys. By moving the mounting surface away from the edge to an off-center position, each pulley can be installed in one of two orientations, which moves the teeth either inboard or outboard. This feature helps bring the pulleys into the same plane, improving the belt line.

Center Track pulleys are currently available in the following sizes:

• Front, 4-Bolt, 104mm BCD: 46T, 50T, 55T
• Front, 5-Bolt, 130mm BCD: 46T, 50T, 55T, 60T
• Rear, Rohloff Version: 20T

Note: 22T Rohloff rear pulleys expected in approximately two months

Center Track belts are currently available in the following sizes: 113T, 115T, 118T, 122T, and 125T.

Happy New Year from Cycle Monkey!

Greetings from our nation's capital! For the past few months, Cycle Monkey has been serving you from the East Coast -- Washington, DC to be exact.

Relocating from Berkeley has triggered some interesting new experiments in the Monkey Lab, while allowing for us to carry on some key Cycle Monkey traditions.

From the start, Cycle Monkey has been a cycle-powered business, with several bikes ferrying goods to local customers and the post office to ship packages to those more distant. For large shipping days, we pull out our cargo bike from Bilenky Cycle Works (Philadelphia, PA). With this bike, we can stack the packages high on the front platform and fill up paniers on the rear rack. Not only does this elicit smiles along the route, but also challenges folks to rethink how bicycles can be used.

Adding to its uses, we have found the cargo bike to be the perfect ride home from the local metro station. There's nothing quite like it in the Kiss and Ride area! Katie has found new joy in railing corners while sitting on the platform, but sometimes wishes she had control of the brakes. Regardless, this experiment has made our family transition to living without a car that much more fun.

Biking is a cornerstone of our business and family. We would like to share this love of cycling with you through this blog. From the Monkey Lab, we will feature our favorite bike builds, components, builders, riders, and rides. Happy pedaling!