Not to worry as it is highly unlikely that I would ever buy one. I don't consider it a reasonable alternative for me.

Did I understand correctly that in order to use the belt drive, you'd have to have a frame with a chainstay that 'breaks', so that you can slide the belt inside the rear triangle?

"Not to worry as it is highly unlikely that I would ever buy one. I don't consider it a reasonable alternative for me."

Me neither, but then I'm not as smart as you and bought one...

"Did I understand correctly that in order to use the belt drive, you'd have to have a frame with a chainstay that 'breaks', so that you can slide the belt inside the rear triangle?"

Yes because the belt is one piece, most likely cut from a tubelar thing, I'm guessing. So it is out of the question for simple applications onto LHTs etc... There are probably some rear suspension bikes that have a monostay design and don't require anything to be done. There are probably some simple folding designs that could be adapted. https://www.desperadocycles.com/Trave...Travelight.htm.

I'm not sure if that was supposed to be a dig at me or not.

Have you toured extensively with it yet? Would you buy it again if you had it to do over?

Even if the technology proves reliable this fact alone pretty much eliminates any possibility of belt drives becoming popular enough to displace chain drives.

Maybe a frame/wheel could be designed to have the cog on the outside of the rear triangle. That way you could have a solid frame and still be able to install a belt.

I think the belt needs some kind of a Sram Powerlink equivalent. If you could disconnect & reconnect the belt and use it on any bike, I would take a serious look at it.

"I'm not sure if that was supposed to be a dig at me or not."

I see what you mean. More evidence against me, I was trying to take a dig at myself. I just got curious about it and the project to get a bike built is taking a while, but at least I have the hub.

"Even if the technology proves reliable this fact alone pretty much eliminates any possibility of belt drives becoming popular enough to displace chain drives."

There is no hope whatsover, unless you just meant on Rohloff and similar gear hubs. For those to become more dominant they need to be mounted on specialty frames, as you are well aware, and the additional changes to make those splitable are not all that bad. To really come up with a neat system the definative sytem, could take a while. The belt has to have some comanding advantage, not mere parity, to be worth it on a touring bike for me.

"I think the belt needs some kind of a Sram Powerlink equivalent. If you could disconnect & reconnect the belt and use it on any bike, I would take a serious look at it."

That would be great, though I wonder if it is possible. Presumably part of the reson this belt can have low "rolling resistance" is because the very strong fibers in it allow a thin back and low resistance to bending. For them to take those loads off something like carbon and transfer then to a steel link sounds like asking a lot. On the other hand if it is really good for very long miles, maybe they could just build a couple of belts into the frame. You would tie one up under the seat as we used to do with tires and then if you burn through two of them come back for a quick pull of the drop , and a re-silvering. If you had some metal in the "chain" area that didn't mind a little heat, or need paint, you could probably go that simple.

Anyone want to throw me a bone here on the price of this stuff, I can't get on the site.

Here's some info from QBP.


CDX11 Polychain

* For use only with CDX11 System which requires the purchase of a ring, cog and belt
* The CDX11 system is intended for Mountain and Commuting applications and can be run with a fairly low belt tension
* Requires the Split Drop Out (FS8000) or frame modifaction for installation
* 11 pitch, 11mm wide and 1342mm long



CDX8 Polychain

* For use only with the CDX8 System that requires the purchase of a ring cog and belt
* The CDX8 system is intended for 'cross and track applications and requires higher belt tension
* 8 pitch, 1mm wide, 1280mm long

Both look like this.




CDX11 Cog

* For use only with CDX11 System which requires the purchase of a ring, cog and belt
* The CDX11 system is intended for Mountain and Commuting applications and can be run with a fairly low belt tension


CDX8 Cog

* For use only with the CDX8 System that requires the purchase of a ring, cog and belt
* The CDX8 system is intended for 'cross and track applications and requires higher belt tension
* Requires the Carbon Drive Split Drop (FS8000), an elevated chainstay or frame modification for installation




The Rohloff cog will be used on the CDX8 system.

This website shows the retail prices.

https://www.bikemannetwork.com/biking/c/COMPBDS

QBP is out of stock on everything right now.

Here is a commuter that already is using a belt drive, you can see that there is no need to break or split the frame to install the belt.

https://www.deltacycle.com/product.php?g=69

My guess is that a belt will outlive a chain 10 to 1, belts made of the same material in the same way last hundreds of thousands of miles under much greater stresses on motorcycles and cars, should last a long time on a low stress bike application.

Since the article that is hyping the belt says 8000 miles I doubt it. On a bike with no dérailleurs and a straight chainline a well adjusted and maintained chain will last a lot more than 8000 miles. Heck I have gotten that on bikes with dérailleurs. My current chain on my touring bike has a bit over 5000 mile on it and still measures out as 12.03" for 12 complete links. Sheldon Brown's site recommends replacement at 12.0625. That would seem to indicate that it might last about the same as Carbondrive brags that they have done on a belt or maybe a bit more. It isn't a particularly high quality chain and most of those miles were done fully loaded on the TransAmerica so lots of mountains and only so so maintenance.

Even Carbondrive themselves (who also say 8000 miles riding on the road) only claim 2.5 times as long as a chain. The 20,000 mile figure came from their statement that they had seen "up to 20,000 miles in the lab".

Looks cool. If they are retrofittable to existing Rohloff hubs, I might try one after I get back home to Oz. For now I'll stick to the tried and tested regular chain+Rohloff.

Looks snazzy though.

I didn't see that in the literature. So your right, if it only lasts twice as long as a chain is all the reason I need to reject this new system!!!

Well you don't need to reject it, but... It would seem to me that to go for a completely different setup than what is proven to work, it should offer substantial advantages. I have yet to see any, not even one that was at all substantial and I see lots of disadvantages.

Even the belt goes as far as they say that is still the same as or less than I am routinely getting on a chain, NOT twice as long.

What are the pluses:
1. Not life of the belt. That sounds like about a wash to me
2. Not repairability. If it breaks you need to have a spare.
3. Silence. Maybe, but so what if you are going to use a noisy Rohloff.
4. Efficiency. Not even in their own tests.
5. Cool factor. Maybe if that floats your boat.
6. Not cost, especially if you have to go to a Rohloff, which would seem to be the only way to get a reasonable range of gears.
7. Not the ability to pick and choose ratios it seems to come in only one.
8. Not availability of spare parts. There is only one source at this point.
9. Not ease of fitting it to an existing frame. You pretty much have to go to some weird frame or go custom at this point in time.

Did I miss any?

Roll your eyes all you want, but at this point in time there appears to be very little reason to go with this technology.

Lighten up! These are not surgical instruments or techniques we are talking about here, we're not saving lives, it's a bike ride, you know wind in your face, smiles, fun and games. New technology tends to have a snow ball effect, one invention leads to another. Rohloff is not the only makes of geared hubs, there are other less expensive options out there. There are also patents out there for variable speed belt drives, maybe someone will perfect a lightweight version.

Even on face value, with a glass half full attitude.
1. The life of a belt is at least as good as a chain. Belt also weighs less and you don't have to carry lube.
2. Not repairable, so what they are different, carry a spare, they are not heavy.
3. Silent, good point! Again, Rohloff is not the only maker of geared hubs, and if belts become more popular, you can bet better geared hubs will follow.
4. Efficient, wash. But as a chain wears and stretches the shifting gets worse, not so with belts.
5. Cool, yea, remember this is all just kid stuff.
6. Cost is all relative. Again Rohloff is not the only maker. Compared to Four wheelers and jet ski's, even expensive bikes are cheap.
7. Gearing, this is a function of the gear hub not the belt.
8. Availability of parts, Oh Lord, ever heard of a cell phone and next day air.
9. Weird frame, yes you need a "weird" frame, or you get to have a cool new frame, depending how you look at the world.

No you didn't miss anything.

staephj1, you kind of make it sound like the bike will catch on fire if you use one of these belts. You have repeatedly stated you aren't going to have one. We get it.

Birdy bicycles from Germany used a belt drive system with an internal geared hub at one point and abandoned it in favour of a chain drive due to durability issues. They were only seeing 500-800kms lifespan on the drive train. That was a few years ago so perhaps the system being discussed has resolved all these issues.

The manufacturer claims 2.5 times the lifespan of a chain. So lets say they are making a 200% lie in hopes of luring Staehpji into buying a belt drive bike, that would mean at least equal durability with chains.

Sorry Staehpji for having fun at your expense, but normal "Glass half full" type folks are not worth the trouble to mess with.

BUT you, on the other hand are not a "Normal", "Glass half full" guy, you are a cross country cyclist. All cross country cyclists have a big kid in them somewhere and it just takes a little coaxing to get him out. So we are just coaxing, that's all. No disrespect meant.

If I had to guess I would guess that that no one else here is going to in the near future either.

No offense taken. It is all in fun as far as I am concerned. I see the whole thing as a argument for the sport of arguing since I doubt that anyone here is seriously considering one. If anyone actually is going to buy one I hope it is someone who will actually tour on it so they can give us a full report.

At those prices I would be wiling to try it. Just to see whether it worked. For me the biggest issue is available lengths, I doubt they are going as long as I want to.

"What are the pluses:
1. Not life of the belt. That sounds like about a wash to me

YOu have to go by more than the belt, it's altogether whether the system wears better, the chain grinds the other parts and the whole system wears out. Which in turn grinds on the belt. 8000 miles is pretty good out of a chain. But either way it would have to be more than just a cost issue. This is going to be a very costly bike, and an extremly costly trip if we are stretching out over multi year distances. It's going to come down to which product one prefers.

2. Not repairability. If it breaks you need to have a spare.

The fact it weighed, what 9 times less would be huge.

3. Silence. Maybe, but so what if you are going to use a noisy Rohloff.

Well at least when you aren't in the crossover gears it might be tolerable.

4. Efficiency. Not even in their own tests.

This all depends on more than tests, chains are nasty afeter a few hundred miles and never roll like they did on day, one. This will be better or worse.

5. Cool factor. Maybe if that floats your boat.
6. Not cost, especially if you have to go to a Rohloff, which would seem to be the only way to get a reasonable range of gears.

Come on, and pulleys are expensive if you have to trade your rohloff for a derailleur system to use them.

7. Not the ability to pick and choose ratios it seems to come in only one.

Could be big problem, but if it is worth it, it will pick up.

8. Not availability of spare parts. There is only one source at this point.

QBP means everyone can have them if they actually make them in quantity.

9. Not ease of fitting it to an existing frame. You pretty much have to go to some weird frame or go custom at this point in time.

Right, big problem, but you can say that about any inovation. It is either going to sell itself off the showroom or not. Think MTBs. not that long ago they were just an idea. If it is perceived as useful frames can be changed easily.

Obviously, I don't think they are ready for prime time, but I am interested in following the progress of whoever takes the plunge. So, who is serious about buying one and what is it about them that makes you interested?

https://www.youtube.com/watch?v=RJGdGw6Z6Sk

Turn the volume up

https://www.cyclingnews.com/tech.php?...007/news/08-28

Carbon Drive Systems: the next big thing?

If you could have a drivetrain that was lighter, smoother, longer lasting, totally silent, more responsive, and required no lubrication, would you buy it? The folks at start-up company Carbon Drive Systems certainly hope so, and they claim its new system not only offers all of the above but a free cup of frozen custard, too (okay, we're lying about the last part, but that does sound good right now. Mmm... custard).

The system is built around a 52g toothed 'polychain' comprised of multiple strands of stretch-resistant carbon fiber embedded in flexible polyurethane. The matching proprietary chain ring and cog are made from CNC-machined aluminum, and the whole shebang weighs just 180g (yes, we said "180g," and no, it's not a typo. Read it again if you must).

The embedded carbon fibers are also said to transfer tension faster than conventional roller pin chains for more immediate response to pedal inputs, and CDS even claims belt lives up to 10,000 miles for its 'endurance' model (a smoother running 'performance' system supposedly offers only marginally shorter lifespans). Gaping ports in the troughs of the cog and chain ring teeth also appear rather capable of evacuating even the nastiest goop, and after eight iterations of design refinement, CDS is confident in the final product.

So what's the catch, you ask? The system will almost certainly be forever limited to fixed-gear or singlespeed applications, and the belt currently cannot be separated and respliced so you probably won't be able to use it on your current rig very easily. However, CDS is working with singlespeed maverick Spot Brand to bring the system to market on a wide range of bikes thanks to a clever 'keystone' dropout that allows users to easily split the drive side chain stay and seat stay with virtually zero visual indication that it's anything out of the ordinary. The dropout is only made in steel for now but CDS says titanium and aluminium ones are imminent.

Spot will offer five CDS-equipped bikes next year, including the Longboard singlespeed 29er, a singlespeed cyclo-cross bike, the Sprawl urban fixie, the internal hub- and fender-equipped Highline commuter, and Spot's standard 26" singlespeed MTB model. Keystone dropouts will be standard equipment across the board, although conventional one-piece dropouts will still be available by special request. CDS also reports that two other companies have signed on for 2009.
Notably absent from the lineup, however, is a full-suspension model. As with any singlespeed drivetrain that doesn't rely on a tensioner, the CDS design is rather intolerant of changes in effective chain stay length as the rear end moves through its travel. While this doesn't necessarily completely eliminate the possibility of a full-suspension rig altogether, it does severely limit the types of systems on which it will work in its current form (dropout issues notwithstanding). Nevertheless, CDS says it has already begun a collaborative project with another well-known builder for a full-suspension model so we'll see where that leads soon enough.
One question left currently unanswered, though, is that of drivetrain efficiency. Conventional roller pin chains are also among the most efficient drive systems on earth, and it's difficult to imagine that a polyurethane belt and its seemingly obvious hysteresis effects can improve on that. CDS is optimistic nonetheless, however, and is currently undergoing third party tests to confirm (or refute) its claims.
Regardless of those findings, CDS reports that Quality Bicycle Products has already signed on to distribute the system and its individual components. A 'framebuilder kit' will also be available that will include a belt, chain ring, rear cog, and dropouts, and CDS is also open to enquiries from other OEM manufacturers who wish to use the drivetrain.
Currently, chainrings are only available in 32/34/42/44T (effective) sizes and Shimano spline-compatible cogs in 16/18/20/22T sizes. Chainrings are only offered in four-bolt 104mm BCD patterns for now but CDS says more chain ring and cog sizes and patterns are on their way. Retail prices for the chainrings and cogs range from US$38-45, and belts will cost approximately US$60. Further information is available on the Carbon Drive Systems web site.