# New Rohloff product?



## fokof (Apr 24, 2006)

Came across that while shopping;

http://www.bikemannetwork.com/biking/p/CR8035

I tried to Google it , haven't found any info.
Anybody knows what it is ?

I tried a search here too without success.

Just curious......

(Speedub.nate , I'm sure you know about that  )


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## rockyuphill (Nov 28, 2004)

It's a actually a carbon belt drive made for a Rohloff hub by Carbon Drive.

Speedgoat also lists it but it is out of stock

http://www.speedgoat.com/product.asp?part=130550&cat=310&brand=1197
http://www.speedgoat.com/product.asp?part=130543&cat=50&brand=1197
http://www.speedgoat.com/product.asp?part=130549&cat=50&brand=1197


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## Speedub.Nate (Dec 31, 2003)

Yep. I'm not exactly in the loop here, but I've been talking to Spot and to Rohloff trying to get my hands on this. I've got a Mrazek frame with an elevated chainstay heading my way, and it's going to be a perfect test bed for the Carbon Drive system.

Last I heard, the Rohloff cog will be available in early '08. Spot supposedly had a prototype at Interbike that didn't quite mesh up with the Speedhub as intended.


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## rockyuphill (Nov 28, 2004)

Hmmmm, and I can disconnect the suspension pivot on my Kona A and make that puppy work as well. Hmmmmmm.

The one thing I haven't seen good data on is the difference in tension on the carbon belt versus a chain. With a chain you just need to take the slack out so there's not a lot of extra load on the BB and hub bearngs (or on suspension pivots on my Kona A). But the belt needs to be tensioned to work. Anyone seen numbers for what sort of belt tension it needs?


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## Crazy C (Nov 22, 2004)

The belt is proprietary. It uses carbon cords to resist stretching thereby eliminating the need for the high tension typically seen with other belt systems. Here's more:

http://www.cyclingnews.com/tech.php?id=tech/2007/news/08-28

http://www.carbondrivesystems.com/


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## Speedub.Nate (Dec 31, 2003)

Newest release date I have for the Rohloff-compatible cog is January 1st, BTW. We'll see...


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## Timbo (Jan 8, 2004)

I'm seriously tempted to try this. Stupid honey pot bike gadget-geekery 

At least it doesn't seem to be that expensive.


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## fokof (Apr 24, 2006)

I'd be curious too !

But one question pops ; I often switch wheel between a Speedhub wheel and a SS wheel , how does that system deals with different ratio ?
The strap must be fix in lenght so , is there different lenght ?

I think in that case we probably have to adjust the chainring/cog accordingly.

With my actual setup , I run a 36/16 combo and 36/18 for the SS wheel , I have enough on the EBB with the chainlenght to accomodate both without having to add pieces of chain.

Wonder about a fixed lenght strap...... probably have to be adjust your ratio for that system.
Or change the chainring wich is a PITA.


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## Speedub.Nate (Dec 31, 2003)

Rumor is that the drive rings and belts are ready. The design of the Speedhub-compatible cog has been worked out, but they're not in production. Yet.

My uneducated supposition is they're going to miss their January 1st target date. 

Anxiously anticipating...

I would still like to see an online calculator, or even a simple lookup chart, that will advise on a belt length for a given chainstay length & ring/cog combo. The Carbon Drive website hasn't been updated since it debuted.


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## rockyuphill (Nov 28, 2004)

Here's one more development in the carbon belt drive world... standardization.


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## patineto (Oct 28, 2005)

rockyuphill said:



> Here's one more development in the carbon belt drive world... standardization.


From the Article.


> The four main Poly Chain players meet to agree standard width and pitch
> 
> It could have been Blu-Ray versus HD DVD, Betamax versus VHS, or a width replay of the 19th Century Gauge War between Brunel versus Stephenson.
> 
> ...


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## Speedub.Nate (Dec 31, 2003)

rockyuphill said:


> Here's one more development in the carbon belt drive world... standardization.


That's phenominal news!

I'm salivating. Thanks for the link.


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## Robert_in_ca (Nov 12, 2007)

Any update on these working with a rohloff?


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## Speedub.Nate (Dec 31, 2003)

Robert_in_ca said:


> Any update on these working with a rohloff?


My understanding is that the Rohloff cog design has been finalized, and some one-offs have been custom made (a couple showed up at the Handmade Bike Show in Portland last weekend), but there were some last-minute delays due to changes with the standard (non-Rohloff) cog. Mind you, that's third-hand through-the-grapevine info.

I wonder, given the news item Rocky posted a few weeks back, if there were any changes/delays due to the standardization agreement between Gates US, Gates UK, CDS, Orange and Nicolai.

In any case, the www.CarbonDriveSystems.com website hasn't been updated since Interbike, and some QBP sites are still saying "Sorry, Item Not Available" while others show various kits and prices (Speedhub kits included).


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## Robert_in_ca (Nov 12, 2007)

Thanks Nate!


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## Duzitall (Feb 4, 2004)

*Yes, Thanks Nate!*

I'm really looking forward to this. I'm thinking a Lenz Milk Money with Rohloff and poly chain would possibly be my next bike.


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## Speedub.Nate (Dec 31, 2003)

New availability dates have been posted on Carbon Drive's website (www.carbondrivesystems.com).

The 24T Speedhub cog is showing August, and the 22T version is showing fall.

Interestingly (disturbingly), the available chainring sizes are 46T, 50T for 4-bolt compact, and 55T for 5-bolt / 130mm BCD.

Quick quick tap on the calculator shows that the 24T Speedhub cog would be best paired with a 56T to 60T ring. The 22T would be best matched with a 52T to 57T cog.

In other words, the sizes available will make it difficult hit / not violate Rohloff's limit of 2.4:1 ring:cog ratio.

If I'm reading the data correctly, the belt pitch is 11mm per tooth, making it possible to calculate required belt length based on chainstay length and gear selection. Those sizes are:
- 1243mm (113 teeth total)
- 1298mm (118 teeth total)
- 1342mm (122 teeth total)
- 1375mm (125 teeth total)

So given the most likely gear combinations I'd run on my 29" bike are 55x24 (2.29:1 ratio) or 50x22 (2.27:1 ratio) -- both a bit under the recommended 2.4:1 minimum -- the available belt lengths work out as follows:

*55x24*
1243mm belt = 15.9" chainstay
1298mm belt = 17.0" chainstay
1342mm belt = 17.9" chainstay
1375mm belt = 18.5" chainstay

*50x22*
1243mm belt = 16.7" chainstay
1298mm belt = 17.8" chainstay
1342mm belt = 18.6" chainstay
1375mm belt = 19.3" chainstay

And of course, since the belt requires either an eccentric bottom bracket, sliding dropouts or horizontal dropouts for proper tensioning, it's just required that the chainstay lengths I listed above fall somewhere inside your range of adjustment.

Lastly, don't take those numbers as gospel. I used 1/2ring + 1/2cog + 2chainstay to calculate them, not taking into consideration the angle from the bigger ring to the smaller cog (which will have the effect of *slightly* decreasing the listed chainstay lengths). Also, this works under the assumption that the belts maintain their 11mm per tooth pitch when the wrap the cog and ring.

It would help if CDS would throw a simple calculator up on their website.


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## luffy (Nov 15, 2005)

so are you saying that in order to run the belt drive with a rohloff, you have to run a ~50t ring? Thats hardly feasible for most techical xc riding, why wouldn't they start with a smaller rear gear?


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## Speedub.Nate (Dec 31, 2003)

luffy said:


> so are you saying that in order to run the belt drive with a rohloff, you have to run a ~50t ring? Thats hardly feasible for most techical xc riding, why wouldn't they start with a smaller rear gear?


A 50T belt drive ring should be approximately the same diameter as a 43T conventional chainring.

I'm not sure how small they could go with a rear cog before running into efficiency problems with the belt. It appears that 22T will be the smallest they offer. It ought to be equivalent in size to a 19T chain drive cog.


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## fokof (Apr 24, 2006)

With those size , not sure about the weight too !

The theorical weight lost of this product probably won't be as good as I tought , those plates being that big.

A 43 ish front for me is a very big NO-NO , we'll see


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## Speedub.Nate (Dec 31, 2003)

On their updated website, Carbon Drive is claiming "a measly 120 grams for the entire system." I don't see how that is possible, but I'm sure we'll be seeing a breakdown of the weights of the individual components soon.


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## Speedub.Nate (Dec 31, 2003)

Here's my take two with the belt lengths & cog combos and how they **ought to** relate to a bike's chainstay length. Because the belts don't stretch, I would be surprised to see any dramatic variations.

This version accounts for the angle the belt makes from chainring to cog, which results in the very slight variation from the chainstay lengths I posted previously.

This still hasn't been vetted with the Carbon Drive guys, but I've emailed them for more info and have asked them to chime in on this post, to correct any errors on my part.

Basically, your choice of ring, cog & belt length will determine the chainstay length required for a workable setup.










Again, worth noting that CDS lists 24T and 22T as the only Speedhub-compatible cogs. Same for SRAM and Shimano Alfine. The only cog listed for Nexus is 24T.

Of the three drive rings, 50T and 46T are 4-bolt compact, and 55T is 5-bolt 130 BCD.

Here's the Mrazek Boh 29"er frame mine will eventually be mated to. Only gotta wait another 6 months!


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## fux (Oct 21, 2006)

Just spotted this on the www..

https://bp3.blogger.com/_4xEIktBAlOg/R90Jlt1WQzI/AAAAAAAAAGo/KY-X2QptDUs/s400/DSCF2878.jpg










The front drive wheel doesn`t look overly huge with the Alfine rear hub..


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## Kikemon (Apr 22, 2007)

One of the bikes at the Portland bike show was retrofitted with a S&S coupler in the chain stay so you could get the belt on and off. I can't find anything on these small couplers on the S&S site. Does anybody know anything about them? I've got a nice Rohloff set up and would love to switch to belt drive but I would need to do something with the frame to make it work (Ti frame with conventional hard tail).


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## Speedub.Nate (Dec 31, 2003)

Kikemon said:


> One of the bikes at the Portland bike show was retrofitted with a S&S coupler in the chain stay... Does anybody know anything about them?


I believe that was the personal bike of Thomas at Rohloff USA in Oakland. You might email him for more info?


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## Speedub.Nate (Dec 31, 2003)

I can't believe how long this is taking.

CDS this week wrote to me that they are waiting on the approval of Rohloff for the cogs they've designed to thread on to the Speedhub.

Upon a thumbs-up from Rohloff, they'll need another 2-3 months lead time to get these parts in the hands of riders.

So we're looking at a March-April timeframe — best case — before this happens... a full year from when this thread was last active!

Sigh...


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## Welsh Dave (Jul 26, 2005)

That's Rohloff Germany for you  

I emailed them on this shortly after seeing the Rohloff belt drive on the 08 Portland NAHBS pictures. 

They effectively said it wasn't likely they'd go with belt-drive, as it "required a special frame/ extra cost" etc. etc., when:

1. A Rohloff-compatible cog already existed;
2. It seemingly had the support of Rohloff US at Portland (Rohloff logos visible in the vicinity of the belt-drive bike).
3. Like a Rohloff hub isn't ALREADY a huge cost for most customers and often requires some adaptation of an existing frame or purchase of a Rohloff-specific frame.

:madman: 

Thankfully, Rohloff US seem to have taken the initiative.
Let's hope they hurry along the parent company into checking and approving the cog design.

Several European manufacturers (Corratec etc) have had Alfine belt drive bikes available to buy in LBS since July 08. Admittedly, these are mostly "town" bikes, but I see no reason why Rohloff couldn't approve this application while they properly check out the long-term performance for off-road or touring bikes.

Nicolai has a reputation for engineering excellence. If THEY can approve the belt-drive, why is it taking Rohloff so long?


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## Speedub.Nate (Dec 31, 2003)

Yes, and to boot, Rohloff USA was playing around with a prototype CDS belt cog for the Speedhub in '07, though that was before the specs changed re: the tooth pitch and width.

There was some speculation on these message boards that the constant tension the belt creates would prematurely wear the bearings and seals (this effect would apply to any hub, not just the Speedhub). I haven't seen anything to support that, but I wonder if Rohloff AG is performing some sort of long term accelerated wear test "just in case" before putting their stamp of approval on it?!?


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## outdoorslife (Mar 31, 2009)

Any news or update when the belt drive cog will be released? On gates/belt drive it says "coming soon" and nothing of substance on the rohloff site. I just got a Titus Racer X 29er Al frame and looking to Rohloff / belt drive it.... Tired of cleaning chains etc


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## fokof (Apr 24, 2006)

Is your frame "opened" on the stays?
The belt is one piece , so you have to put it "in" the rear triangle somehow. Check the photo of the answer #23 , you can see that you can "Split" both stays in order to fit the belt in.
I don't think you'd be able to do that on a RacerX......


Don't know about the release date......


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## outdoorslife (Mar 31, 2009)

Yes it is, sort of.  See the pic I attached. I have to take the screws out of the rear part and separate the chainstays from the seat stays, but its doable. :thumbsup:


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