Tag Archives: Di2

Bike Of The Week: 2012 BH G5 with Shimano Di2

The Bike of the Week has returned in fine fashion, celebrating the arrival of the 2012 BH G5 Di2.  The latest iteration of the G5 frame continues to support the Shimano electronic platform and includes an integrated Di2 battery mounting system on the underside of the downtube, near the bottom bracket, and thus lowering the bike’s center of gravity.  The G5 in this week’s edition of BOTW wears a 2012 Shimano Dura Ace Di2 kit, a Dura Ace 7900 SRM power crank, and Dura Ace CL-C24 carbon clincher wheels.

The G5 frameset continues to utilize an integrated seatpost design, increasing the stiffness of the frame while reducing overall weight, making the bike perfect for racing and spirited training.  The G5 continues to be a fixture on the local competitive cycling scene under riders from the BH/Comedy Central team, with this particular bike’s owner proclaiming that her G5 is “the most fun I’ve had on a bike.”  Don’t take her word for it, stop by for a test ride of your own.

Domo Arigato, Mr. Shimano

In the workshop, “the sound of shifting is changing from subtle clicks to the whir of a dancing robot”.

Di2 Front Derailleur

With multiple 2011 Tour de France stage wins for Campagnolo’s electronic shifting system, and the entire podium riding with Shimano’s DI2, it’s no wonder that electronic shifting is a hot topic. So, what’s it all about? Electronic shifting is functionally identical to mechanical shifting, the rider tells the shifter what to do, the shifter moves the derailleur, and the derailleur moves the chain from one gear to another. The only difference is the method of communication between the shifter and the derailleur.

Di2 Shift Lever

With a mechanical system, the shifter utilizes the hand strength of the rider to move a lever attached to a cable. A system of ratchets and pawls (not, as has been rumored, mystical miniature Italian or Japanese laborers, but that’s for a different article) in the shifter mechanism create finite movements that pull the cable just the right distance. These “indexes” allow the derailleur to align perfectly with the gear of choice. With the electronic system, the force of movement is powered by small motors in each derailleur, and a microprocessor tells the motors exactly how far to move. The shifter mechanism becomes simply a switch, with two buttons telling the motors which direction to move. Some advantages of this being that the shifting no longer relies on hand strength, and eliminates the numerous intricate small moving parts of the shifter mechanism. This also makes electronic shifting far less influenced by it’s environment. Current electronic systems are well sealed from the elements, Campagnolo claims it’s electronic system will function even while completely submerged. By being impervious to water, dust and road grit, these aspects no longer effect the relationship between the shifter and the derailleur.

To understand why electronic shifting is a significant leap forward, it is important to point out what is eliminated altogether. Cables are the Achilles heel of any shifting system. No amount of mechanical precision in either a shifter mechanism or derailleur will make a difference if the cable is not traveling smoothly through it’s housing. In the 50′s and 60′s, housed cable systems were standard equipment on bicycles. However, Raleigh along with other bicycle manufacturers of the era still produced bicycles with rod and lever actuated brakes for foreign export to places like India and South Africa. Although the housed cable system was well established at that time, the climate and inaccessibility to spare parts in these regions facilitated the need for the antiquated yet more reliable and serviceable rod systems. Housed cables have come a long way since then, but one muddy cyclocross race or rainy Spring Classic can wreak havoc on the vulnerable housing/cable interface.  Another issue is compressibility. Since pressure is applied to both ends of the housing, the compression changes the effective length of the housing. Modern housing is designed to resist compression by incorporating strands of wire running it’s length, but input of the shifter is always a finite movement to the derailleur, so any slight change in the distance between the two can effect the adjustment of the shifting. Shimano lists 100 common reasons for poor shifting in their mechanic’s handbook, of them 34 are cable/housing related.

Di2 Diagnostic Tool

While traditionalists may consider electronic shifting to be a gimmick, signs point to it becoming the standard for bicycles. Campagnolo has invested over 20 years in research and tooling for it’s electronic groups, a major gamble for a company as steeped in tradition as they are. Shimano’s offering of an Ultegra level electronic package suggest that the concept can be close to a reasonable price. As with all electronics, the drive of progression is in lowering in cost as well as product improvement. The future of bicycles it seems, belongs to electricity.

BOTW: Felt F2 Electronica (Di2)

Not many stock bikes can match the F2‘s blend of light weight, stiffness, strength and handling. It’s this balance, achieved through meticulous engineering and advanced carbon materials, that makes this bike shine.

Spec’d with some serious components, including Dura-Ace Di2 shifters, FSA K-Force cranks, Ultegra brake calipers and Shimano carbon wheels, this bike is race-ready and under 15 pounds.

You could pay an extra $5000 for the F1, but you’d only be saving a pound … with little if any performance difference between the two. You might as well invest that extra $5000 (if you have it) on that custom bike you’ve always wanted.

BOTW: Ellis Di2

Dave Wages, who began building frames under the Ellis Cycles name in 2008, spent only a little time test-riding Shimano’s Di2 group after its introduction, but he was so immediately impressed with it, he decided a Di2-specific bike would be the perfect for the then forthcoming 2010 North American Handmade Bicycle Show (he would go on to win the “Best in Show” category).  He wanted to match Shimano’s innovation and execution by brazing a steel frame to suit the parts.  “It’s a cliche,” he said, “but don’t ride the stuff unless you want to buy it.  It’s that good.”  The frame Dave eventually built reflects his ideas about what a Di2-equipped bike should be–the kind of bike he would ride.  He said he wanted performance to be the first priority since Di2 is such a worry-free, always-working set of parts.  And so the geometry tends toward “race” rather than “comfort.”  This is no giant-tubed carbon reverberation chamber, though: it’s a hand made, lugged, silver brazed piece of purposeful craftsmanship, and the ride is everything one would expect from the most current in steel tubes (from Italian manufacturers, Dadacciai and Columbus).  It’s a bike that, Dave admits, “paddles against the tide” when it comes to trends in the bike industry, but the numbers speak for themselves: 15.5 pounds for a fully built steel bike.

The design, seamlessly integrating Shimano’s top of the line group, says cutting edge as well.  There are no derailleur cables, so there are no braze-ons to clutter the lines of the bike.  The rear brake cable is routed internally, giving the appearance that there are no cables at all.  Dave also wanted the Di2 wires routed as cleanly as possible; in some spots, like that of the front derailleur only about an inch of insulated wire is exposed.   For years Dave has been routing rear derailleur cable through the drive side chainstay, and he chose the same path for the Di2–the workmanship here is particularly elegant with the derailleur wire emerging from the dropout reveal and running smoothly through a tiny brazed ring.  The dropouts themselves are unique to the Ellis brand, Dave’s own design.

To finish the frame off, Dave chose an appropriately tasteful color which is difficult to represent accurately in photographs, a pearlescent gray that looks at times silver, at times blue.  The bike is topped off with the kind of light-weight parts that don’t need to be looked after.  Hed’s Stinger 4 wheels are a good depth for road riding while maintaining a strong aerodynamic advantage.  This bike begs to be ridden, even raced, and like those hand crafted steel frames ridden in the grand tours forty years ago, this bike will stand up to a lifetime of enjoyment.

What makes this bike even more unique is that unlike most of our BOTW’s,  this one is both on display at the shop and on SALE!   At $7,750, it’s a hell of a deal for a “best in class” machine.