Saturday, April 24, 2010

Gates Carbon Drive- A Review

The boys in Golden treated me great when it came time for a replacement frame. The new Spot is great and I'm loving the Paragon sliders.  My only gripe, the Gates Carbon Belt Drive.  I can't get the damn thing to work right.  The alignment looks dead on, the tension is high, but, when I really torque down on the cranks, it makes a popping or "snapping" sound.  The belt doesn't slip, I'm not throwing my knees into the stem or anything like that, but this sound is VERY nerve racking.  It always occurs when you really need your drive-train to work and work flawlessly, on a steep pitch on some insanely technical climb.  It is at this moment I need to focus on the task at hand, not worry about the snap, crackle, pop coming from my rear wheel.

Even at cost, converting to a belt drive is not cheap. It's a major investment that one "should" be able to rely on.  Now, in all fairness, the system is phenomenal 99.8% of the time. It's light, quite, requires almost no maintenance and provides instantaneous power to the rear wheel.  Several reviews mention this perceived power to the wheel and I was skeptical.  I found myself going back to a chain drive recently and noticed a lack of responsiveness when the chain was installed.  I ran the chain for a local 12 hour race and went back to the belt drive a few days later.  There is a noticeable difference between the two drives when it comes to crisp transfer of power.  The belt drive puts power to the wheel instantly and effectively.  Combined this with the reduced weight, lack of required maintenance and long life span and this should be the perfect system. Should be.

I've aligned, re-aligned and re-re-aligned the belt ad nauseam.  I've added tension to the point I heard the BB bearings cry "uncle".  Then, I'd re-align the cog once more.  Out on the trail things appear to be great until that first big, steep pitch that requires an all out effort, then "SNAP!".  That sound that sends chills up my spine.  WTF!  This is getting old.  Well, I'm pretty heavily invested in this drive, and really want to give it a fair shake, exhaust all avenues if you will, so, I drop another $40 bucks on the little "belt tension indicator" Gates sells (along with a smaller cog (for more money than I'm comfortable discussing right now)).  I re-install the belt and align, re-align and re-re-re align the cog a few thousand more times and then throw the tension gauge on there to see how far off I was with my own guesstimate gauge.  Well, I had a little too much tension in the belt (according to the Gates do-hicky) and back it off a smidge.  Considering the belt has already made the snapping sound at a higher tension, I'm not overly optimistic things will improve with reduced tension.  Still, I follow the directions and figure these big brained people know what they are doing.

Today's ride proved one thing, those guys, in their white lab coats and fancy computer models don't know shit about real world mountain biking on a single speed.

Edit: Gates Carbon Drive System is sending me a new belt as a warranty replacement.  Initial setup/tension may have been incorrect (my fault) and the good folks at Gates are not holding it against me.  They stand behind their product and were very helpful when I called....which they suggested I do after reading my review.  This level of customer service is impressive!


YUEQ said...

Thanks for the review. I stay with chain and fancy Boone ring/cog.

Tim Darwick said...

I have the cure to all your snapping-gear woes:

Pennsylvania is such an innovative state...

biker27 said...

How about contacting us at Carbon Drive System to help to troubleshoot your situation. We have years of experience with the system setting up bikes. 303-278-3955.

Todd said...

I'd like to thank Steve at Carbon Drive Systems for all his help. He's sending me a new belt at no cost and had some good suggestions to get the drive working properly. Exceptional service! Thanks Steve.

Anonymous said...

did this get resolved with the new belt? what ratio are you using? I'm having the same issue with my new drive - Steve at CDS has been helping me as well - new belt is on its way. I'm hoping it solves it all...'

Todd said...

It definitely got better and doesn't pop as much as it did before, but, I can't say that it's 100% trouble free. I got the tension very high and it will still make a snapping sound once in a while (once or twice a ride) on a hard effort.

I'm running a 39x24 most of the time and I did pick up a 22. Steve @ Gates told me you have to run really high tension with the smaller cogs due to reduced contact area, but, I can't run anything larger than the 39 up front due to clearance. I already have to use 2 full and 1 half size spacers on the drive side so the chainring won't shred my chainstay. I can't run anything larger up front. Hell, I've toasted a BB cup because there are so few threads in the BB shell and the tension is so high.

I like the system, I just never had this many issues with a roller pin chain. I certainly never had to be "gentle" with my chain drives and they cost a lot less.

Anonymous said...

I also have a gates carbon belt drive equipped bike, my ride is an off the shelf bike (Fixie Inc Peacemaker) and funnily enough I have had the same issue that you describe from day one of ownership, the bike is still very ridable and brilliant, but as mentioned I also get the loud clunk sound when really cranking off from a standstill. At first I assumed it was my alignment or tensions setup, but I have tried everything. The bike supplier has had the bike back 4 TIMES! and the issue still continues, they are convinced it is a rear hub issue, I would love to hear how you got on?

Todd said...

Anonymous, Gates sent me the second belt and it worked fine for one race and a couple rides. I made sure to set the tension on the high side (per Gates recommendations) and things worked ok for a little while. However, I started to have the same problems again and decided to ditch the belt drive. It's just too unreliable, finicky and expensive. The Cons of the system far out-weigh the Pros. I met another rider who used the system with a Rohloff and he had the exact same problems, went through several belts and finally gave up as I did. I would love to find someone who has good luck with the belt drive. My follow-up post is here:

Anonymous said...

Thanks Todd, i'm on the case for a new belt to test, do you know where I can source one of those belt tension testers, I cannot find any reference to them besides on Gates installation guides?

Todd said...

I got mine from Universal cycles:

I was thinking about what your LBS said about the hub and I really don't think that is the issue. It sounds like your belt is slipping a tooth just as mine did. The problem is, once you slip the belt, the carbon has become compromised and the problem will only get worse. Adding tension is only a temporary solution. You need to buy a new belt. The free replacement Gates sent was great, however, the new one failed just as fast. The added tension also stripped the threads on my drive side external BB cups. For me, that was the final straw. I was done with the Carbon Drive and went back to a chain. No problems since and I love my bike again.

Anonymous said...

Problem with snapping belt may entirely be related to your frame. Not all frame builders are yet aware of the requirement of high belt tension, and what it means to frame design. My guess is that your frame is giving way when you really mashing it - there is now way to cure this other than buying a frame that incorporates a fortified triangle design. (Such as the frames).

Todd said...

Anon, I am sure the frame is mostly to blame. I believe I mention that in the third follow-up review I did. Just too much flex happening at the BB I think. Problem is, I own a Spot Brand bike. These guys have been one of the original adopters of the Carbon Drive system and I have a sneaky feeling the two companies are run by the same guys and from the same location. So, if anyone should know how to build a bike that will work with the CDS, it should be Spot. Unfortunately for me, that does not seem to be the case.

I've seen a review of a belt driven bike from Mi-Tech. Seems they have really done their homework and built a frame that works well with the belt drive. However, it also sounds like they had to make the frame very stiff. The reviewer said he was pretty beat-up by the end of his time with the bike. That completely defeats the reason I ride a nice, compliant steel frame. I love the ride you get with steel. It feels great to pound through rock gardens or spend hours on the bike. I would not give up a great riding frame just so I could run a belt. That seems ludicrous to me.

Anonymous said...

Hi again, yes I suspect you are right about the frame flex, as I have tried every tension level and a 2nd belt, which is slightly wider than the original spec but seems less prone to ratcheting.
I do wonder if a wider belt equals more pulley/teeth 'coverage' equating in less ratcheting?
The bike manufacturer is somewhat mainstream so you think they would have done their R&D, or maybe I just have super hulk quads that the frame just can't handle :D
Needless to say, the CDS has never let me down, even when running inefficiently it sill carry's on, I've learn't what I can form all this and am currently in the process of spec'ing my own Ti frame for a CDS/Alfine commuter.

Todd said...

I'm sure it was your super hulk quads. ;-)

The belt never "let me down" in the sense that I got stranded on a ride. However, it let me down from a cost/expectations standpoint. It costs a lot to run a belt and you'd expect it to work as advertised. I know most of my problems probably came from too much frame flex and I can't blame Gates for that. However, there seems to be numerous people all having the same problems (yourself included) all with different brands of bikes. That says something to me and it's not something good.

I think your Ti/CDS/Alfine commuter will be fine, incredible even. As I mentioned in one of my posts, I think the CDS makes the most sense on a commuter. It just can't handle the demands of mountain biking. Keep me posted on your new bike and send some pics when you get it built. I'd love to hear about it.

Anonymous said...

One possibility may be the belt pitch. From what I find on the Gates CDS website, they are using belts with 11 mm pitch. Schlumpf in Switzerland is also developing their Advanced Belt Drive System (I'm in no way associated with Schlumpf, by the way, nor have used their system so I don't speak from experience).

You can read the technical details at but the summary is they have chosen to go with belts having a 14 mm pitch for more "bite" on the cogs/sprockets. This may eliminate the slipping problems you're encountering with the Gates CDS.

Also, as wonderful as the weight savings and high modulus of carbon fiber is, Gates may want to consider using conventional steel cable reinforced belts. They won't be that much heavier than carbon fiber (especially when compared to the overall weight savings you're gaining over dispensing with a conventional bicycle chain) and they won't suffer from the fragility of carbon fiber (fragile when bent, crimped, twisted, etc.). Plus, they would be cheaper than carbon fiber. Or at least Gates may consider offering it as an option; steel or carbon fiber, take your pick.

Another option may be to offer belts with Kevlar fibers instead of carbon fibers. You would get high strength, low weight, and none of the fragility associated with carbon fiber. So now it becomes three options; steel, kevlar, and carbon fiber. Each would be marketed to a different segment of the bicycle population with different price points for each. Product diversification.

Since reps from Gates obviously read this forum, are you listening?

While we're at it, consider putting some R&D into figuring out how to make a belt that can be separated so we don't have to make bike frames with a split just to accommodate the belt. I know some manufacturers are doing this now, but it will be a fad. The vast majority of cyclists are not going to dump their old bike to buy a new one just so they can install a belt. If you want your belt drive to survive the fad stage, you'll need to figure this problem out.

Todd said...

The Schlumpf system is an engineering marvel, however, I would never spend that kind of money just so I could run a belt drive. It also looks like you would add weight over a traditional chain drive. First, you need the speed drive (@ $700) with its 2 speed planetary gears so you can run cogs large enough that the belt won't ratchet. Then, you need to bolt the appropriate number of plates together depending on the pitch of your belt, for both the front and rear rings/cogs. No mention of the price for those goodies, but, I bet it's a bit more than the already expensive Gates CDS drive.

I'm a single speeder, which means I'm both lazy AND cheap. Shelling out the extra cash for the CDS was hard enough, but, I thought it would reduce the amount of time I needed to maintain my drive-train. The cost was acceptable IF I saw those benefits. I did not. I experienced more maintenance and additional expense. That didn't sit well with me.

The Schlumpf system is amazing and (like I said before) an engineering marvel. I'm just not about to spend that kind of money to beta test another product that probably won't work as well as my chain drive.

As a buddy of mine once said, "belt drives are a solution looking for a problem". He is a wise man.

Anonymous said...

Agreed on not beta-testing the Schlumpf belt drive. It wasn't my intent to suggest you buy it. I was aiming the comments I made more at Gates than anyone in the hope that they would look at what pitch size Schlumpf is using as a possible solution to the slipping problem that appears to be cropping up with the Gates system.

And the Schlumpf system is not without its drawbacks (cost and weight being two you've already identified). For example, the largest front belt disc will be 42 teeth and the smallest rear disc will be 26 teeth with no intention of making anything larger or smaller, respectively, per an e-mail response I received back from Schlumpf. Consequently, you wouldn't be able to use their belt drive with a Rohloff Speedhub because you wouldn't be able to maintain the minimum 2.35 ratio between the front and rear cogs required by the Speedhub. At least, not without violating your warranty with Rohloff.

Another drawback is - despite designing in mud ports on the sides of their discs - the Schlumpf drive has no provision for shedding mud out the "bottom" of the troughs like the Gates system does.

Why were my comments not addressed directly to Gates on their website? Because I visited their site and also watched their YouTube videos. Too much marketing hype and too likely to have received a response back to the effect of,

"Thank you very much for your interest in the Gates Carbon Drive System, the next evolutionary step of the bicycle drivetrain! Gates is an innovator in belted drive systems. UNCHAIN YOURSELF!, yada, yada, yada..."

While here - on an independant forum expressing the opinions of people using the system under real-world conditions - they're more likely to take note and listen to the critiques of their product.

My intent isn't to bash their product. To the contrary, I think it holds great promise; especially for recumbent riders (of which I am one). When your chain is three times as long as a conventional upright bicycle, anything that can be done to eliminate the chain weight is a welcome innovation. But it needs to be refined and improved upon and hopefully Gates will take that to heart.

Anonymous said...

I had bought the Scott SUB 10(2012 model) from a local bike shop which is using the CDC version. In the first month, there weren't any sound, and it was really a bliss riding such a quiet bike.

However, the terrible snapping/cracking sound start to occur from then onwards whenever I put torque onto it. Countless trips to bike shop(mechanics couldn't even figure out what the hell is wrong) and I even had the friendly folks from Gates to send me a free rear cog to see if it solve the issue. Tried adjusting the tension and all to no avail.

Temporary fixed I did was by lubricating the belt with a dry lube wax every few rides.

I'm thinking that the latest CenterTrack version may not have such an issue?

Todd said...

Sorry to hear about your Scott Sub 10. I'm really surprised it was spec'd with the older CDS version. I know Gates still sells it, but, I thought it was more for parts. Any new bike really should be running the newer Center Track drive.

Gates sent me the new Center Track after reading about my experiences with the original CDS. I will say the new Center Track CDX is amazing. Much better than the previous version. I actually wrote a review after spending a little time on the new system, The drive is still working flawlessly.

If I were you, I'd contact Gates and ask about a warranty replacement or upgrade to the Center Track. Honestly though, Scott should be the one eating that cost. They should have NEVER spec'd a 2012 model bike with the original CDS.

Let me know how it goes and what you end up doing. If you get the Center Track, I think you will be happy.

Anonymous said...

Thanks Todd, will definitely try out your advice with the warranty. Had chance upon your blog because of this and that's when I realized I wasn't the only one with such an issue.

Had read your latest post about the new Center Track you had installed. Am so glad that work out flawlessly for you! :)

Day Company said...

I have a Schindelhauer bike with the Gates Carbon Drive, and granted it is an urban bike, so this doesn't seem to relate directly to the issues having to do with a mountain bike, but I have to say I have found the Gates system very nice. And I think Schindelhauer designed the bike with the Gates system in mind, which probably makes a somewhat important difference. Just my two cents worth.

Anonymous said...

I just stumbled upon your problems.
There are some blogs that describe the problem with the CDC system on Fixie bikes. Actually the frame is way to soft and bends when you strongly hit the pedals. Then tension is gone and the belt slips.

I have a Trek/Diamant 247 bike with the old CDC belt and never had any problem. And I have 20kg panniers and 10% steep ascend. The frame is so stiff it never bends.

Todd said...

That Trek Diamant looks really nice. I've always felt the belt drive is perfectly suited for commuter bikes.

Sadly, I have snapped 3 Center Track belts on my Spot single speed. I believe the belts get compromised when I hop over logs and such while out on the trails. Once that happens, it's only a matter of time before the belt breaks. I've gone back to chains, for good this time.

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