With more and more of the bicycle industry jumping on board with Gates' carbon belt drivetrain system, It's starting to look like the belt drive is here to stay. Framebuilders are offering more frames with split sections of belt installation, Big name bicycle manufacturers are spec'ing city bikes and some single speed mountain bikes with belts, and high end part manufacturers like Phil Wood are producing belt drive specific hubs, cogs, and sprockets. Belt drivetrains have a lot like about them. They do not require lubrication or much other maintance for that matter and are extremely quiet and smooth. The belt drive is supposed to be the all weather, all year 'round, any and every condition solution for serious commuters.
Well, needless to say, folks in northern climates like us were very excited about this as a solution to harsh winter coomuting conditions. We had a customer ditch a car in favor of a Civia Bryant. The bryant is spec'd with an Alfine internally geared 8 speed Gates belt drivetrain. This seemed like THE end all of commuter bikes. Not long after completing the bike we got hit with a snowstorm. We were all excited to see how the Belt drive would perform in the slush that the snow turns into on the roads. The first ride in these conditions proved to be disastorous with the belt slipping off the rear sprocket mid commute. This problem arose everytime the roads were slushy and snowy. Curious about this experience I surfed the web to see if anyone else had experienced this. I found a really good account of this issue here .
As you can imagine in a place where there is a lot of snow and slush for several months on end this is not good. A good commuter bike set up should be one in which you can rely on and can be confident in its ability to get you where you need to go. We spoke to Gates about this issue and they recognized that the belt dropping in slushy/snowy conditions is a design flaw in the internally geared sprocket design. The single speed sprockets have cut-outs in them that allows for slush and other debris to clean out of the belt track during regular use. This design is simply not possible for internally geared hub sprockets. Here is what the sprocket looks like:
The problem is when slush builds up in the grooves the belt looses its grip on the cog and slips off.
After talking to Gates for a couple weeks a prototype for the new solution to this problem was sent out and it looks promising.
The new system for internally geared hubs has a flange down the center of the rear sprocket with cuts in the grooves and a slit in the belt. This should keep the belt on track while slush and other nastiness clears out through the cut-outs in the grooves. The new belt is compatible with Gates' standard front sprocket.
It sounds like Gates will be offering this as an upgrade rather than a warrenty issue due to it only being a problem with those of us who live in extreme winter conditions. Gates is hoping to have this sytem in production later this spring. With a fresh 28" of snow on the ground we are very excited to see how this new and improved belt drivetrain will fare!