mkane77g

We use a timing chain and haven't had a tattoo in over 20yrs.

WNY tandem

We purchased a spare belt and carry it with us in our trunk bag. The extra weight isn't enough to worry about and having it with us in case we need it would make life a lot easier keeping the Stoker happy!

Krenovian

When I first set up our belt drive, the CDX CenterTrack version, I set the tension to approx. what was recommended on the Gates website for the CDC version. At this tension a significant amount of effort was required to spin the cranks compared to a timing chain setup on the bike stand. I backed the tension way off and this made it much easier to spin the cranks. I don't have any quantitative data but qualitatively it now feels similar to a timing chain setup. I don't think there is much room to decrease the tension on the CDC version but the CDX version allows for quite a bit of variation without any problems with the belt slipping or coming off the rings and where you set the tension for the belt will make a huge difference in the effort required to spin the cranks. I don't know how the tension we are running will impact belt wear in the long term.

The Friction Facts results were obtained with the belt set up at the Gates recommended preload of 85 lbs. Their report refers to the belt as the CDS version. I'm assuming this is the CDC belt and not the CDX. It would be interesting to see the CDX system tested at some different preload values below the 85 lb. setup. I'm guessing the differences between the chain drive and the belt drive systems would narrow considerably at lower tension settings for the CDX belt.

Curt

jfarwell

thanks for posting this note. For a moment I thought it was just me. I ran into the very same thing. I backed off the tension and completely changed the feel of the bike.

Pic

After a fellow tandem captain pointed out the effort needed to spin the cranks, I purchased a tension gauge. It was set at 80 - 85 lbs. The recommended CDX tension is 55 - 85lbs, so obviously in tolerance, but at the high end. I had my LBS set the tension to 60lbs. Definitely a little easier. Would love to see any official result testing.

Carbonfiberboy 

We had our CDC belt set as loose as we could and still have it track. Whatever the watt loss might be, we ride a lot in the rain here in the PNW, which is a big reason we tried the belt. We wore the rings out in only 1300 miles to where the belt would no longer track. We went back to the chain. With the CDX version the tracking would no longer be an issue, but then it isn't an issue with our chain, either.

IMO, the only real advantage to the belt is not getting chain marks on my clothing when loading and unloading the bike from a vehicle, and the ability to put stuff on top of the NDS of the bike when it's laid flat. I do miss those things. I have a discarded medical smock I wear to load and unload the bike, to the amusement on onlookers. I suppose I should also put on a pair of latex gloves. Once mounted of course getting a tattoo is not an issue.

Gates replaced our rings and belt under warranty, but would only replace with CDC, not CDX, so the warranty parts will just sit there, since there are losses and they'd just wear out again in a few months. I can't see spending the money on a CDX setup, since the rings obviously wear much faster than a 9-speed timing chain.

DubT

Carbonfiberboy said, "Gates replaced our rings and belt under warranty, but would only replace with CDC, not CDX, so the warranty parts will just sit there, since there are losses and they'd just wear out again in a few months. I can't see spending the money on a CDX setup, since the rings obviously wear much faster than a 9-speed timing chain."

We have over 5,500 miles on our CDX drive, I did replace the initial belt after picking up some foreign object that caused it to partially come off the pulley. Gates said that it might be OK but, recommended that it be replaced. The belt had around 4,000 miles on it. 4,000 miles is about what we would have gotten out of the chain. The advantages that I see for the belt is it clean, quiet, lighter weight (it reduced the weight of the bike by 1/2 pound) and hopefully it will have a long life. Similar belts last thousands of miles as timing belts on many current automobile engines. The CDX rings at 5,500 miles are not showing any wear.

Wayne

waynesulak

Good example of different strokes for different folks:

Carbonfiberboy in the Pacific Northwest rides a lot in the rain and finds the belt setup not durable enough.

DubT has no durability issues but if I recall correctly rides much less in the rain.

We only load the bike in the car once every few months so the advantage of the clean belt in the car is minimized. We also wax our chains so I don't use gloves when working with the chain. Any very small amount of black transferred from the chain wipes my off fingers very easily with a rag.

twocicle

We recently did a very wet (read: RAINY) 2 week road tour with a bunch of other tandems. Four or five of this group had Gates belts, either CDC or CDX setups. None of us had any problems related to the wet and sometimes mucky conditions and all of us greatly enjoyed not needing to maintain (clean & oil, repeat, repeat, repeat) a timing chain during the tour.

Additionally, I recently made an inquiry with FSA support tech and the Gates topic came up. Let's just say that FSA was much aware of belt tensioning and that, in their opinion, too many people overtension their belts which results is premature BB bearing wearout.

FWIW, the CenterTrack setup we have is still in great condition. I run our belt somewhat looser than the Gates spec, and so it seems our cranks spin a little more freely than when I test the belt at the spec tension. The formula I use for belt tensioning is embedded between my ears. Sorry, not portable to your iPhone

A couple of us packed a spare belt for backup, but those were not needed. I loop my belts (ie: DO NOT FOLD) in the same manner as they are shipped when new. That requires a little faith on the final loop where you need to apply a little twist to get the belt to flip into a uniform 3-loop state, then drop it into a USPS cardboard envelope. This is probably the safest means of transporting the belts while traveling.

waynesulak

Did you did have to oil the drive chain regularly on your wet tour?

teamdonterri

About 18 months on the Gates belt with no issues or visible wear to pulleys. Runs clean and quiet.

bikeinxs

Loved our belt until it broke climbing a hill after about 400 km of use. Gates refused to warranty it. Installed as per directions. Left us stranded in the boonies and we were lucky to get a ride. We've gone back to a chain and I continue carry a couple of spare links and a connector in the saddlebag.

We do quite a few long rides every year. The tiny weight savings wasn't worth the risk of another failure in my opinion.

Also, chain tattoos? Seriously?

merlinextraligh

Given that it broke at 400km, its highly probable that somewhere along the line, installation or otherwise, the belt was twisted in a manner not prescribed braking the internal fibers.

We broke a belt standing out of the saddle on a 10% grade hammering in the big ring. That belt had been installed incorrectly. 4 years later, still using a belt, we've had no breaks.

And why were you stranded? The stoker can still pedal you home, albeit a bit slower.

bikeinxs

Absolutely it was mishandled somewhere. I have no illusions about my strength. I've been working with timing belts in automation for almost 30 years and fixing bikes long enough to be certain it wasn't me that did it. I'm now out of pocket because neither Gates or my LBS will warranty it.

Mine also broke hammering up a steep climb, one week before our "A" event of the season. If we had gone for an easy ride that day instead it likely would have broken somewhere in the middle of that "A" event, also without any warning. My point being is that you have this very fragile and delicate timing belt. You have no way of knowing if it's any good or not other than if it doesn't break while riding it. I can inspect just about everything else on my bike and tell when it's starting to wear out but I can't detect that. I'm sure that you and I are not the only ones who have had belts fail like this.

As far as being stranded, yes, my stoker could have gotten us home and had it been flat that wouldn't have been too bad an option. The time deadlines of babysitters and such add a different perspective. We're not talking about life and death here we're talking about degrees of inconvenience and annoyance. I'm sticking with my reliable timing chain.

merlinextraligh

And I think you have a fair point. With 5 years experience with Gates Belt drive, I'm a bit on the fence whether I'd spec it on a new tandem.

I'd summarize the pros and cons like this:

Cons:

1)Cost, more expensive than a timing chain set up, however, the difference has gone down a lot, and is pretty small compared to using very light chains, but is still significant if you use cheaper chains.

2) lack of field serviceability. Properly handled, I don't think the belt is more likely to fail than a chain, but a chain is easy to repair. Unless, you're touring with panniers, carrying a backup belt really isn't practical.

3) friction loss. My bet, based on looking at the limited data, and our experience running the belt at a lower tension than spec'd, is that the Belt tensioned just high enough not to skip has slightly more drag than a chain but not as much as the reported data indicates.

4)Wear. While durability is touted as an advantag for the belt, in our experience, the pulleys wear out much faster, than timing rings. Caveot hear would be that this conclusion comes from the original system. We don't have enough miles on the center drive system to reach a conclusion regarding the center drive system.

Pros:

1) weight: 4-10 ounces lighter depending on what chains and rings you compare it to,

2) maintainence. No cleaning, no oiling. Not sure how big of advantage that is when you have to clean and oil the drive train anyway.

3) cleanliness. it is nice to have one side oil free, particularly if you're putting the bike in a car.

4) "connectedness" between stoker and captain. We definitely feel like we have more immediated feedback through the pedals with the belt.
Running a chain at higher tension, might mitigate some of this advantage.

5) Bling factor. People always comment of the carbon fiber belt.

On balance, for us, it's a close call. So far, the "connectedness" element has kept us favoring the belt.

oldacura

This appears to be the newest thread on pros/cons of chain -vs- belt.

Since the center-track belt & pulleys are out, does anyone have long-term experience with them? How do they wear long-term? Is this truly maintenance-free? Do they ever squeak?

Does the limited number of belt / pulley choices limit the crank center -to- crank center choices? Is this an issue?

I really appreciate you early adopters.

fietsbob

The Gates Chain wheel cogs are a Bit too much on the weight saving side
(LBS has a Broken Trophy of one breaking on a Tour and the rider had to hang out for 4 days to get a spare in ,

I read Florian Schlumpf in Switzerland has a Aluminum metal crank "belt" ring that is more durable than the Gates ones.

Now sold in Germany as the CHF is too expensive .. haberstock mobility - Home - haberstock mobility GmbH


Products - haberstock mobility GmbH

DubT

we have been running the center track system since June of 2012. We put 3,500 miles on the first belt and while on a ride picked up some trash that causes the belt to come part way off of one of the pulleys. I managed to get it back on and we finished our ride. I called Gates and they suggested that I replace the belt as I may have broken a fiber and if so the failure can be catastrophic. I installed my spare belt and I now has around 12,000 trouble free miles on it. The pulleys are showing absolutely no signs of wear and I have not had to adjust the belt. Clean, quiet, no maintnence and light. What more do you want. Yes there is a specific crank center to center required, any reputable builders I'll know what that is. I would not even give chain drive a thought. If they squeak you can lube them with silicone spray.

wayne

Carbonfiberboy 

We now have the center track belt on our CoMo. We run the tension as light as we dare and haven't had a skip. We've only had it on since early May, about 700 miles ago. We bought the setup from Universal Cycles for $233. I think it will last longer than the CDC since ring wear won't cause the belt to slip off. The CDX ring teeth look like they are coated with a tougher wear preventative than paint. So far no bare metal showing on the teeth. It was the teeth that wore out on the CDC setup, not the belt.

We tour with the belt. We figure we can buy rings and 2 chains at any bike shop. It is nice to have the better feel between captain and stoker.

WNY tandem

This is our second season running the CDX setup and not problems at all. We also are running it with lighter tension than suggested with no skipping. We have enjoyed it so much that we have converted several of our tandem friends into installing on their bikes too!

merlinextraligh

I honestly don't recall when we put on the CDX belt, but we weren't far behind the first teams using it. We've put about 5,000 miles a year on it, so we're definitely over 10,000 miles.

With the CDX we can run lower tension, without skipping . Looking at the rings, they're definitely worn significantly, but no effecto on operation yet.

We're sufficiently happy with it that we did end up specing it on our new Calfee.

oldacura

So - CDX pulleys have a center groove and no flanges - correct? Are the pulleys aluminum or plastic? I think that we are planning on a left side sync chain (belt). I didn't follow the thread on the right side sync so I'm not aware of the advantages. I'm sure that as with most things, there are advantages & disadvantages.

merlinextraligh

The pulleys are aluminum, and yes there's center groove, no flange.

bikebark

We have had a CDX belt for almost two years and have over 6000 miles on it including lots of miles on gravel and loaded touring. We also run lower tension on the belt. The only problem we have had was one time a stick popped up and got caught between the belt and ring causing the belt to come off, but not causing any damage. We carried a spare belt when we toured in Cambodia and Laos but never needed it. Our rings are showing minor, insignificant wear which I suspect is mostly caused from by sand when riding on gravel roads. I definitely like the fact that the belt stays clean and that we do not have to clean it after riding on unpaved roads.

sch

Local tandem shop had a machine with belted timing and drive with a Shimano 11spd internal hub. No FD, no chain. Hub needs 5 ml of new oil/yr.
Attraction, minimal maintenance, belt costs $75 per shop owner and lasts 25k miles or so. Sounds very attractive. Internal hub needs total change
in shifting however, you shift only while not pedaling so even with close coordination some momentum loss on hills is unavoidable.