Gear Review: Gates Carbon Belt Drive System

Belt drive-maker hoping to win hearts of single speeders with latest version

Belt drive systems are used in cars, industrial equipment and motorcycles, why not bicycles?

Belt drive systems are used in cars, industrial equipment and motorcycles, why not bicycles?

I consider the bicycle to be one of man’s greatest inventions of all time. Why? Because in more than a century of its existence, the bicycle is essentially still powered by a chain and cog. If there were a better, more efficient way to power a bicycle, companies like Shimano would have already figured it out.

But the folks at Gates aren’t convinced a chain is the best way to drive a bicycle. Although a patent was filed in 1890 for a belt driven bicycle, since then, the challenge of making the belt stiff enough to not flex or break while staying on its track has proven elusive.

Gates updated the original belt drive to include a keyed center track to keep the belt from migrating off. It works flawlessly.

Gates updated the original belt drive to include a keyed center track to keep the belt from migrating off. It works flawlessly.

That is until industrial belt drive pioneers Gates Corporation developed the original Carbon Drive System in 2007. Although plenty stiff, the original Carbon Drive System still had issues with alignment and staying on its track. In 2011, Gates released the CenterTrack and CDX systems, featuring a groove down the center of the belt which lines up with machined fins between each chainring and cog tooth, keeping the belt perfectly aligned while requiring less system tension.

An automotive strap wrench makes a good chainwhip for Gates cogs.

An automotive strap wrench makes a good chainwhip for Gates cogs.

The Gates Carbon Drive belt is made of stretch-free carbon fiber tensile cords covered by a weather-resistant polyurethane outer. Although the belt is remarkably strong, bending, crimping, and/or twisting it the wrong way can bring it to a premature end. Even transporting it improperly can do damage–Gates prescribes a particular coiling of the belt to prevent damage to the carbon fiber cords should you need to carry one.

And though you may be tempted to use the belt as a chainwhip to remove a Gates cog, don’t. This too is belt killer. Use a strap-type automotive oil filter wrench instead. It works perfectly.

Like any new kind of technology, the Gates Carbon Drive system takes some getting used to. First off, all the gear inch calculations you’re already used to with chain driven systems get thrown out the window. Instead of familiar gear ratios like 32:21 and 34:19, you’re dealing with oddball numbers like 46:28 or 39:26.

The Gates system made the feathery Ibis Tranny even lighter—it weighs in at about half that of a traditional chain and cog drive system.

The Gates system made the feathery Ibis Tranny even lighter—it weighs in at about half that of a traditional chain and cog drive system.

And because you can’t cut and adjust the length of a belt like you can a chain, once you figure out the proper gear ratio, you’ll need to order the correct belt length. Measured in number of teeth, the CDX belt comes in eight different lengths.

Because each gear might potentially use a different belt length or at least require an adjustment in the frame tensioning system, easily running a “dingle”speed option – two different gears that run the same chain tension—is pretty much out of the question. Not a deal breaker for most buyers, but something to consider nonetheless.

The Gates Carbon Belt Drive is clean looking and performing.

The Gates Carbon Belt Drive is clean looking and performing.

Another minor annoyance with the belt is figuring out how much tension to run. There’s two ways to properly measure the tension—a Gates tension meter or the Gates smartphone app. Because the app is free and with me whenever I have my phone, I downloaded it and gave it a try. The app works by listening to the tensioned amplitude of the belt when you pluck it like a bass guitar string. It shows the recommended Hertz range and tells you at what frequency your belt is vibrating.

Although a pretty slick idea, I could never seem to get three consecutive accurate readings from the app. And further, my belt tension always seemed lower than what the recommended tension was. Because I was running the Gates system on my Ibis Tranny 29, the frame tensions by telescoping behind the bottom bracket. I literally sat my entire body weight on the bike to tension the rear triangle, cinched down the Slot Machine bolt on the Tranny 29, and I was still below the recommended tension.

After that I gave up and simply took a rather unscientific “tight enough” approach. It’s worked fine for me with no slippage at all, so I’ll just stick with it. The app does have a few other handy features though, including a complete product catalog of all cogs, rings and belts as well as a calculator to figure out specific gear setup so you know exactly what ring, cog and belt to use.

Continue to Page 2 for more on the Gates Carbon Belt Drive System and full photo gallery »

About the author: Kurt Gensheimer

Kurt Gensheimer thinks the bicycle is man’s most perfect invention. He firmly believes ‘singlespeed’ is a compound word. He sometimes wears a disco ball helmet. He is also known as Genshammer. He is a Gemini and sleeps outside in a hammock.

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  • CrashTheDOG says:

    Thanks for the thorough review. I’m currently spec’ing out an Ibis Tranny and you’ve convinced me to go with the Gates system. Also, I’d love to see a photo or two of your Ritchey Breakaway setup with the Tranny.

  • twain says:

    Great article & review.

  • Dan says:

    Great stuff. I’ve personally ran both old and new Gates Carbon Drive technology and the latest is a huge improvement and so sweet. Also knowing the importance of belt tension made me wonder how well the Ibis Tranny tension design would work for belts. I use the Gates “cricket” fingure tool to check tension.

  • Woody Woodpecker says:

    Absolutely brilliant. IMO, the chain has always been the weakest link in the bicycle. It’s messy and needs constant cleaning and maintenance. I want to have this installed on my steel single speed frame.

  • Padrote says:

    Standard chains when used on a single speed mountain bike are already quiet, almost never break, and take two minutes to clean. Not to mention if you’re traveling you’ll want the ability to change ratios easily and frequently. Pass.

  • Angry Singlespeeder says:

    To Padrote’s point….yes, if you are a constant gear ratio tinkerer (which I am not), the Gates Belt Drive system is probably not for you. Over the past five years on my singlespeed, I have maybe run three different gear ratios, so having limited gearing options is not a problem for me. I pretty much stick with one gear for most conditions. A 46:28 on the Tranny 29 works awesome here in Tahoe, where there are some mega climbs at altitudes above 8,000 feet. So take that for what it’s worth.

    – ASS

  • Ken says:

    I am considering the Gates belt drive. I have read a study where the belt system was determined to require additional rider wattage output over a comparable chain system. Have any of you belt riders noticed an increase in drivetrain drag or reduction in power output?

    • Allan says:

      I too have read this article, I haven’t noticed any difference, perhaps it’s offset by the weight reduction ,
      I think if we were to look at the actual % in power reduction loss of wattage , to the greater percentage of riders out there , negligible difference.
      I also read that having a clutched RD decreases the performance in a full suspension bike by increasing drag on the rear movement .
      My greatest increase in performance comes from a few less beers and a good nights sleep

      • Ken says:

        I also note that the article pertaining to the friction and wattage loss of the belt system is based on a prior iteration of the Gates System and is directly related to the amount of belt tension. As I understand it, the newer center track system requires less belt tension? Anybody know how much less tension? I also see where people have been able to run the new system with less tension than that specifically recommended by Gates since the new system eliminates most of the belt tracking issues?

  • Angry Singlespeeder says:

    Too many drawbacks? Not really. Silicone spray…you *might* need to spray it once every month (big hassle I know). And carrying an extra belt…it’s not required. People who’ve been running the belt system have been getting years of life out of their belts, so unless you’re on multiple years of use on the same belt, you probably don’t need to carry one. But really, a belt weighs 80 grams – another big hassle I know.


  • Allan says:

    I have a spot honey badger with belt drive , LOVE IT , the belt drive is whisper quiet near as no maintaince required , I ride a lot in coastal sand dunes and love that my drive train isn’t being devoured by salt and sand , I fully reccomended this drive system , I weigh 103 kg (227 lbs ) and when standing giving the pedals everything I have to climb this system has been faultless . oh and it looks cool

  • PinkFloydLandis says:

    The Gates app does not “listen to the tensioned amplitude”. It is “listening” to the tensioned frequency.

  • Ashley says:

    I cycled from Key West to Canada and then back to Mexico along the great divide with a Gates / Rohloff 29er: I used two belts, carrying the used one as a spare rather then walking out: never needed it.
    I carried an eye-dropper of lube which I used in the desert (much less lube than a chain drive needs). The bike made less noise and was more reliable, lower maintenance than any chain drive, especially thru mud and snow.
    The rear sprocket was completely consumed by the 7,000 miles, I would recommend changing both belt and sprocket and changing the oil at 3,000 mile intervals for harsh conditions. Or maybe better maintenance en route rather than riding thru puddles to wash the mud off!
    A couple of times the belt came off. Mud glued gravel to the chainwheel and prised the belt off: Of course I should have stopped when I felt the resistance, and anyway the wheels were glued to the frame by then and I had to carry the bike after scraping it to make it portable.

  • dave says:

    Anyone know of any more aggressive mountain bikes that are compatible with a carbon drive? Something along the lines of the Stanton Slackline or Chromag Stylus? (Something that can ride occasionally at the local dirt jumps and flowy bike park trails?)

  • SinglespeedMTBer says:

    I have been running the belt drive for three years Spot rocker now Ibis Trany. I climbed a million feet last year around 600,000 feet this year so far. I love the belt drive. I am 200lbs and the first belt broke after 2 years and thousands of miles of hard riding and only because it had a ding from a rock in it. I would have gone through about 5 chains and a couple cogs and probably a ring in the same amount of time. I will never go back to standard chain system. If you break a belt it means you did something wrong. I love never having to lube it or tension it. It has never slipped on me ever, if your ride a SS and ride a lot and your not using a belt drive your missing out big time

  • Eric says:

    I have an Ibis Tranny and tried to use a 46 but DS chain stay clearance and cog placement (absolute end of the hub) turned me off. I replaced with a 39.23 but suffer from popping. I suspect I will have better luck going back to the 46? In any regard did you do anything special in fitting your 46? I am using an 770 XT. Thanks for the great article and thanks in advance for your reply.

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