Unless you're a history buff or in the ball bearing industry, Schweinfurt, Germany, probably isn't a familiar location. Since the late 1800s, when Freidrich Fischer invented a machine for mass producing ball bearings, this river-side Bavarian township has been at the forefront of the world's bearing production. Schweinfurt also played a role in the early days of the bicycle industry – Sachs began manufacturing the Torpedo freewheel hub here in 1903. After suffering heavy losses during World War II, the town rebuilt during the Allied occupation, going on to become the manufacturing hub that it is today.
How does this relate to the modern day mountain bikes that we ride? In 1997, SRAM moved in and acquired Sachs, improving their own European distribution and adding manufacturing clout, a much needed shot in the arm for the American company that was battling to find a stronger foothold in the
drivetrain market. The Schweinfurt location now serves a vital role not only in the European market but also worldwide as their Development and Training Center, otherwise known as SRAM DTC. The DTC facility is just one of sixteen locations, spread across nine countries, that SRAM calls home. While only a fraction of SRAM's employees are located in Schweinfurt (130 of 2500 people who work for SRAM worldwide), it is an integral part of the entire operation - not only are European dealer services run through DTC, but it is also the main location for drivetrain development. This includes all stages of product evolution, from designing, to in-house manufacturing of prototypes, to lab testing. It is also under the DTC roof that SRAM's XX 2 x 10 drivetrain was developed, as well as where the soon-to-be released XX1 eleven-speed group was conceived and born.
European Dealer Service Direct
While much of SRAM's drivetrain development takes place within the DTC building, the Schweinfurt location also serves as home base for their European DSD (Dealer Service Direct) operations. This includes service and warranty issues, where products are reconditioned by technicians at dedicated workstations, each equipped with tools and supplies for any issue that might arise. Saying that the men in this room are well versed on the ins and outs of SRAM, RockShox, and Avid componentry would be quite the understatement. Shops in need of technical support, or those who are just looking for an update on a service item can call and speak directly to a technician via Bluetooth headsets that each man wears. The DSD area is also home to the classroom work stations where SRAM teaches dealers and mechanics how to service their products. Eight work stations, complete with repair stands and drain tanks, allow students to learn how to work on everything from the most basic RockShox fork all the way up to the latest BoXXer, to bleeding Avid brakes or performing a full service of a Reverb seat post.
The DTC building is imposing from the outside, but its massive size becomes even more apparent once you've entered the structure and passed through the showroom, popping out into the cafeteria (shown below). Examples of championship-winning bikes sit above each booth, casting a shadow as you eat your third helping of sauerbraten followed by one (or five) packages of Haribo gummy bears. A high-end espresso machine at the far end of the room serves as the water cooler rallying point for the SRAM engineers and other staff. A set of imposing doors, complete with a myriad of different warning signs on them, make it very clear that this is where the tour would end if you waltzed into the DTC building on your own accord. Our group has been given free reign of the facility, though, allowing us to pass by the display of vintage Sachs hubs beside the doorway and enter into a seldom seen world where the components that we use, and will use in the coming years, are dreamed up. It is probable
that the engineers we met would likely be toiling away on 2014 and 2015 products if they weren't in the midst of giving us a tour of the facility, but of course, those sorts of things were hidden from view before we even got close to those big doors.
In order to develop the XX1 drivetrain for production, SRAM first had to understand the forces put through the components in the real world. In this case, the real world involved both riders of average skill and pro-level athletes that would push far past the boundaries of even the most advanced weekend warrior. Early prototypes were taken out to the mountain and the bike was fitted with multiple data acquisition units, including a Quarq power meter. This allowed the engineers to keep track of gear choice, cadence, power, and many other real-world variables. These metrics were then used to not only develop more rigorous experiments, but were also fed into specially designed test rigs that allowed technicians to duplicate those very same conditions for an interminable amount of time, including to the point of failure, while under observation in the lab.
What looks to be some sort of high-tech exercise machine is actually a test rig, although we're betting that whoever saddles up on the 'DeMONSTRator' is in for a workout regardless. Again, data collected from actual riding can be imported into the machine, allowing the operator to simulate real-world conditions. If, for example, there was a need to replicate a specific scenario that needed to be played out again, but this time under the watchful eyes of SRAM engineers, it would be run on the DeMONSTRator.
Shifting in a Box
While its likely you've seen XX1 under SRAM's BlackBox riders by now, the components must also stand up to abuse from everyday, average shredders, day in and day out. With this in mind, SRAM needs to know how the system will react to countless hard shifts under heavy pedalling forces, which is why the rig above is equipped with a load cell that measures the forces involved in a simulated abusive riding environment. The test, which is run behind protective polycarbonate panels, allows technicians to focus in on the strain performance of the cassette, chain, and shifter.
The seeds for the XX1 rear derailleur were actually planted eight years earlier when engineers at the DTC facility were investigating the feasibility of a derailleur dedicated to pure DH use. The first prototype (above, left) was a 9spd unit that could be used with a standard range cassette; holding it in our hands it seemed to weigh as much as three or four production XX1 derailleurs. Remember, though, that weight is the last concern at this early stage of the development phase. This first prototype employed a 'straight parallelogram' that moved directly across the cassette, a concept that SRAM has christened 'X-Horizon' in reference to its horizontal plane of movement that differs from the angled, 'slant-parallelogram' design found on all modern derailleurs.
The slant parallelogram is necessary to keep the derailleur's upper guide pulley close to the cassette cogs while the pulley cage is busy trying to reel in and play out excess chain as the front changer is shifted between chain rings. It wasn't until years down the road that the Straight P concept was looked at again when SRAM began development of a single-ring drivetrain for all-around use. The second prototype (above, second from left ) was born a few years later, and is much slimmer in design and works across a 10spd cassette. This was also the first appearance of the large cable pulley wheel, a feature that would carry through all the way to the final production version (above, far right). Interestingly, it wasn't until the third prototype that the radically offset upper pulley was utilized - notice the upper pulley's position well behind the cage pivot - likely signaling SRAM's intentions to pair the derailleur with an immensely large cassette spread.
Given the DH origins of the XX1 rear derailleur, we have to wonder if SRAM has plans for a drivetrain, or at least a rear derailleur, devoted to pure downhill use. And yes, we mean a unit far more singleminded than the current X0 DH derailleur with its shorter P knuckle. SRAM had no comment on the matter at this point in time.
The XX1 cassette, with its massive 10 - 42 tooth spread, has been the talk of the new component group. And while we're used to seeing the impressive finished product, the cassette begins life in a much different form - a steel ingot (above, left) that roughly resembles the cassette's final profile. It arrives at SRAM's Taiwan manufacturing plant ready to be machined down close to its final shape (minus the teeth profiles), a process that takes place in a single, labour intensive step. While this is a serious operation that would be simpler to perform over a number of different stops along the way, this single-stage approach to the cassette's manufacturing means that the unit does not have to be transferred between machines, thereby ensuring perfect alignment over all points. A milling machine adds the tooth profiles, shifting features, and the pins that hold the large, 42 tooth cog in place. The XX1 cassette uses steel for ten of its eleven cogs, but the dinner plated-sized large cog is a separate aluminum unit that is held in place by way of pins machined into the backside of the largest steel cog. Forging is used to attain the large cog's basic shape, followed by a stamping process that forms the tooth profile, as well as the splining that will mate to the XD cassette body. All told, it takes well over three hours of production time to even begin to see the cassette's final form, with multiple hardening and finishing steps still needing to be performed. Despite the additional cog and large spread, the finished product weighs in at about 260 grams, making it one of the lightest cassettes on the market regardless of its size.
Our visit to Schweinfurt also included three days of riding aboard an XX1-equipped Liteville 301, a bike that you'll soon be able to read about in a full-length review. The local trails were certainly smooth, fast, and full of flow, but the riding was still trumped by being let into the inner sanctums of SRAM's DTC facility. It is behind these usually-closed doors that an immense amount of product development takes place, with the end result usually adding up to some combination of lighter, faster, and stronger.- Mike Levy