My Civia Bryant is the 6th belt drive bike I’ve ridden. The others were a Norco Ceres, Dahon Mu XL Sport, Raleigh Alley Way, Trek Soho (test ride only), and a prototype Bryant back in 2009. I rode some of these other bikes for a month or two, but this new bike is the first belt drive model I’ve personally owned and ridden everyday as my primary commuter. It’s been a fun and interesting two months.
By now, the benefits of belt drives are pretty obvious:
- Durable (double the life of a typical chain)
And, the limitations are fairly well-known as well:
- Require a dedicated split-frame
- Only compatible with fixed gear, single speed, and internal gear hub drivetrains
- Sensitive to drivetrain alignment and rear triangle stiffness
- Can make it more difficult to remove the rear wheel (depends upon the bike)
It’s probably obvious by now that I’m a convert to belts, at least on commuter bikes. Besides the obvious advantages listed above, the near silent, direct, and buttery smooth feel of a belt can become quite addictive. In just a couple of months, this has become my new normal and now chain drives feel coarse—and dare I say—even a bit crude by comparison (I’ll catch flak for that).
That said, belt drives are not without their challenges. Set-up is fairly critical and support at the local level can be spotty. It behooves the home mechanic to gain an understanding of how belt drives work and what steps are required to set them up properly. Fortunately, Gates provides excellent support both on their website and via email. For those who don’t do their own maintenance, I’d make sure your local mechanic is well-versed in belt set-up prior to purchasing a belt drive bike.
On my particular bike, I had an issue with the rear pulley (cogs and chainrings on belt drives are called “pulleys”). Mine is a 2010 model, and apparently, there were issues with a small number of alloy pulleys from that time period. As I mentioned, I’d ridden a number of belt bikes, so I knew what to expect, and the drivetrain on my bike was noisier and not as smooth as it should have been. Gates was great and sent out a replacement pulley at no charge, which solved the issue. The silver lining is that troubleshooting the problem taught me a bunch about how to set-up belt drives.
Setting up a belt drive is not all that difficult, but the methods are different than those that are required for a chain drive, so it’ll feel foreign at first. Chains are forgiving in that they flex a fair amount laterally, plus they run on a toothed sprocket, so alignment is not that critical and slippage is not an issue. Belts require relatively precise alignment between the crank and rear hub to keep them running on center, and belt tension needs to be within a specific range to prevent slippage. Belt drives on bikes are no different than automotive belts in this regard.
New belt bikes come from the factory with the front and rear pulleys aligned, so that’s not a concern for the home mechanic. What is important to understand is rear wheel alignment and belt tension.
Belt tension is set by either moving the rear axle, or by moving the bottom bracket via an eccentric. How this is done varies from one bike to another. Belt tension is best checked by using a Gates “KRIKIT” tension meter, a simple operation that literally takes only a second. Gates and the bike manufacturers provide tension specifications for individual bikes, but in general, belts are run at somewhere between 40-60 lbs. Once belt tension is set, it will not need to be adjusted again for quite some time since carbon belts have zero stretch. If a belt does loosen up, it’s because of wear in the other drivetrain parts, not stretch in the belt.
Regardless of whether belt tension is adjusted at the rear axle or at the bottom bracket, rear wheel alignment determines where on the rear pulley the belt rides. What you’re shooting for is as close to the inside flange as possible without actually rubbing on the flange. This provides the most slip-resistant belt line and silent running. Moving the non-drive-side axle forward causes the belt to run closer to the inside flange of the rear pulley, and vice versa. What I do is move the non-drive-side axle rearward until the belt clearly starts moving away from the flange, then creep it slightly forward until the belt almost, but doesn’t quite touch the flange. The final adjustment point may or may not result in the wheel being perfectly aligned within the chainstays.
All of this probably sounds a little complicated and involved, but the reality is that it’s no more difficult than setting up indexing on a chain drivetrain (for example). I’m convinced it’s simply unfamiliarity with the process that makes it seem difficult to those who haven’t done it. At this point, having gone through the steps a few times, I feel as confident working on a belt drive as I do working on a chain drive.
After the initial challenge of troubleshooting my noisy belt, followed by identifying the issue and replacing the offending part, I’ve yet to touch the drive. It’s been absolutely silent and smooth. The best thing is that it requires zero maintenance and I shouldn’t have to do anything more than give it a squirt with the hose for the next few years.
Disclosure: Gates is a sponsor of this website.