Gates Carbon Drive Experience
June 16, 2011 9:06 AM
Gates Carbon Drive Experience
words and photos by Peter DiAntoni
COG’s first introduction to the Gates Carbon Drive System was at the SSCXWC in Portland back in 2007. I remember Chris DiStefano riding around on a Spot bike equipped with the Carbon Drive System the day before the main race. The bike seemed obscure, yet interestingly simple. For the qualifying race Chris lent the bike and his racer number to pro racer Shannon Skerritt. His masquerade didn't last for long. Shortly after the race began, Shannon appeared walking with the bike and a snapped drive belt.
It was pretty easy to scoff and snicker at this new technology back then, though not discounting the power of a pro racer to achieve belt destruction. After this awkward introduction to the Gates Carbon Drive System, COG had little interest in following its progression.
In August, 2008 COG took a visit out to Trek HQ in Waterloo WI. A watershed moment occurred at the end of our tour when one of their engineers brought out a ridiculously light bike from their test lab running the Gates Carbon Drive System. We were simply stunned. The experience of riding that test bike has stayed with us to this day. COG departed wanting to know more about the Gates Carbon Drive.
The Gates system seems to be making its way onto some really interesting bikes. One of these bikes is Trek's Carbon District. Right now it's the only Carbon Drive, full carbon frame in production. Immediately upon discovering this bike, COG reached out to acquire it from Trek for a road test review and for use as our team bike during 2010's Riverwest 24 hour bike race. Trek was receptive to this idea, but the Carbon District is an elusive and rare breed at Trek. There was only one available, sitting pretty in a photo studio somewhere in Pennsylvania.
The Trek Carbon District arrived at Trek HQ the day of the race. As luck would have it Breakaway Bicycle Courier had a driver dispatched to Madison en route back to Milwaukee at exactly the same time I received the call to "Come and get it!" An hour later the Carbon District was in Breakaway's dispatch office being severely ogled by the messenger staff.
Names like Death Star, Dark Horse, Lord of Darkness and Black Magic were thrown at it.
The Carbon District is deserving of them all, sporting covert black on black graphics and sexy space-age curvatures. The bike is also dead silent when pedaling. Pure Ninja power.
After the initial shock and awe subsided, I became very interested in the rear dropout design. It was not at all clear to any of us how to take the rear wheel off. I called up Trek and someone familiar with the bike walked me through it over the phone. The task seemed easy enough...loosen three bolts on each side of the wheel, loosen and pull out the wheel skewer, then go for the eccentric bolt on each side of the wheel and turn until the guide pins match up. Pull the dropouts apart slightly and voila, the rear wheel is off!
Slightly fearing the unknown, our team did not attempt to remove the wheel at this time. I kept the information in my head and blasted off to the race registration.
Upon arriving I met the rest of the team and everyone gave the bike a quick run around the block. All systems go at this point. Captain Jake was the first rider up and after completing the first lap on the course, something became painfully obvious.
The stock gearing on the District Carbon is 55:22 using standard Gates front and rear pulleys. This works out to approximately 65.8 gear inches per pedal stroke. Jake came through the start/finish screaming: "It's too light!!! I can't keep up with them." Jake was referring to our competitors dropping into their big rings on the long flat and downhill sections. Okay, we'll just have to spin it out. The District Carbon was like no other bike I've ever experienced coming up the hills though. The frame is just incredibly stiff and almost gave the illusion of being pulled uphill.
The real tragedy of the race came upon our first rear flat slightly after midnight. It was very clear to me in my disoriented full race mode state that we should have taken the wheel off earlier to practice and prepare for such a disaster. We had no idea what to do! Thankfully our good friend and trusted wrench John Trusky came to the rescue. It only took us a mere 30 minutes to change a rear flat!!! That was the first time. The second, rear flat came one lap later on the cusp of a torrential rain storm. Another 30 minutes with Trusky's help and a fresh, 25c Conti tire swapped in for the stock 23c Bontrager and we were off again. From this point on the Carbon District was flawless and took us over 336 miles through the 24 hours of racing.
That was the tumultuous beginning of my love affair with Trek's District Carbon and the Gates Carbon Drive technology. Coming from riding steel track bikes for the last eight years, I'm all for simplicity. The carbon belt drive is simple, once set up properly. The District Carbon was designed specifically to accommodate the belt drive. Trek devoted countless hours to engineer the rear eccentric dropout. Now that I've spent more time and hundreds more miles on this bike, I can truly appreciate the work that went into it. There is a slight learning curve to removing the rear wheel, but once mastered, will reveal the genius of the design.
As previously mentioned, the Carbon District comes standard with a 22 rear pulley. This can easily be swapped out with a 20 which provides a much more realistic ratio, given that the OCLV carbon frame was meant to go fast. Yes, the District Carbon is the first bike I've ridden which actually becomes more stable that faster you ride and quite noticeably upon steep descents.
My life has forever changed through this experience with the Carbon District and the Gates Carbon Drive.
As if one carbon drive bike experience wasn't enough, it wasn't.
Earlier in the summer I received Spot Brand's new street/track frame which was awaiting Carbon Drive components. The Spot frame is at the other end of the spectrum from the Trek. To begin with, I've built the Spot up part by part, where the Trek came ready to roll, dialed to perfection. I had no idea the problems that lay before me to dial in the Carbon Drive from scratch.
What immediately caught my eye with the Spot bike is their use of True Temper OX Platinum tubing. It's the first modern steel tubing I've been in contact with, and there's a tangible difference coming from Reynolds 531. The first being: the bike is super light and stiff. Throw in true track geometry, combined with the Carbon Drive and you've got the most responsive, hair-trigger street weapon imaginable.
Back to setting up the Carbon Drive from scratch. It was no easy task as standard chain lines have no relevance to belt lines. One very critical point on a Carbon Drive bicycle is you must achieve a perfect (+- 1mm) belt line. This is especially true when setting up a fixed gear. The belt must go forward and backward just as smoothly. Thankfully Spot has plenty of experience with the belt drive, as they utilized the Kobe Slider Dropouts on this frame. Once proper belt tension and alignment are setup, this is a true set-it-and-forget-it system. There's never a need to adjust belt tension when removing the rear wheel.
There are a couple major hurdles involved setting up from scratch, but I'll save you a couple of week's worth of trial and error and skip to the solution...Phil Wood. Leave it to Phil's impeccable engineering and innovation. They have bridged a gaping hole in the Carbon Drive market. In all my calls to Gates and Spot, never was I told a third party developer existed for the Carbon Drive. Only by attending Interbike this year did COG discover what Phil Wood was up to. Their recent creations compliment the Spot/Carbon Drive system perfectly.
First, we'll start with Phil Wood's adjustable spindle bottom bracket. Essential for fine tuning the belt's line. Phil's bottom bracket allows up to 5mm of travel which is more than adequate to dial in a perfect belt line. Pair this with Phil Wood's new Carbon Drive specific 120 spaced ISO fixed/free large flange rear hub and you're now good to go. Flipping the wheel from fixed to freewheel maintains belt line perfection when matched with Spot's vertical sliding dropouts. Also, Phil Wood teamed up with White Industries to create what is arguably the most bomb-proof belt drive freewheel in existence at this moment. It's a stout handful at 505g, but when you subtract the weight of a standard chain, the set up is actually lighter in total grams than a traditional chain drive.
The more I ride the Carbon Drive system, the more I'm sold on it. Some of my many moments of enlightenment include the following: the first time I lubed the belt with clean, fresh water! When riding fixed or free, there is an absolute lack of "chain slack". It is the ultimate direct drive feeling. And I'm sure I won't miss the nostalgia of greasy pant cuffs, chain marks on calves and cleaning grease off chain drive components... A big thanks goes out to Gates, Spot and Trek for blazing a trail into the future with the Carbon Drive system. I'm a true believer!
Trek District Carbon
Spot Brand It looks like Spot discontinued the model in our review with the track geomentry, but they still have some killer bikes...
Phil Wood
Gates Carbon Drive