Author Topic: KMC overhaul packaging, introduce wide 1/8in e-Bike Rohloff sprockets, more  (Read 748 times)

Danneaux

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Hi All!

Looking at KMC's site, I see they have overhauled their packaging and (announced May 2019) introduced new drivetrain components for the e-Bike market:
http://kmcchain.us/2019-new-e-bike-product-line/
These now seem to be widely available through a variety of outlets. KMC promises extended drivetrain life: 3,500+km for narrow derailleur-compatible components and a "guaranteed" 10,000+km for wide 1/8in components including a sprocket compatible with the Rohloff splined carrier and chainrings intended for Bosch mid-drive motors and what appears to be 104BCD chainrings:
https://www.kmcchain.eu/10000km+

The line includes chainrings for use with the Bosch mid-drive units including the new Gen3 models and one pictured that appears to be intended for 104BCD crankarms, but I have not had much luck finding a listing for it.

KMC's e-Bike chains are labeled e1 (for single speed and hub use), e9, e10, and e11 for derailleur use, and one very special chain -- the e101. It offers a 10,000km+ warranty when used in conjunction with wide KMC Sprockets and Chainrings:
https://www.kmcchain.eu/chain-KMC_e101_EPT-e_bike-wide

KMC's 1/2 x 1/8 (wide) sprocket for the Rohloff splined carrier is made from 1/8in thick chromoly (not stainless) steel with a black finish and promises a 10,000km+ lifespan and is available in 15-21t, compatible with the 1/2 x 1/8 KMC e101 EPT single speed chains:
https://www.kmcchain.eu/sprocket-KMC_Rohloff_Wide-e_bike

Given how some of our members have achieved this sort of mileage with current Rohloff-supplied sprockets and good aluminum or stainless chainrings and existing chains, it is fun to speculate whether these new components might result in even greater drivetrain life when used with human power only for touring in a variety of conditions. Certainly, 1/8in drivetrain components last longer in my own fixed-gear use; the additional surface area better distributes wear across the wider sprocket and chainring teeth and the chain rollers and bushings are wider. Of course, chainline has to be spot-on because these chains don't tolerate the lateral deflection common in derailleur drivetrains.

Best,

Dan.




« Last Edit: December 30, 2019, 05:22:55 PM by Danneaux »

Pavel

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Thanks for posting this Dan. 

These Chains made with E-bikes in mind, is there any reason that they would not work with a regular Rohloff Nomad?
« Last Edit: December 30, 2019, 06:38:35 PM by Pavel »

Danneaux

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KMC's line of e-Bike products should work with "regular" (solely human-powered) Rohloff hubs, Pavel.

If their 1/8in products are used, then chainline has to be spot-on and for maximum life, all components should be 1/8in as well.

KMC's e-Bike oriented chains in derailleur sizes should work fine with standard Rohloff sprockets and standard aluminum alloy or stainless chainrings.

It seems what makes these e-Bike chains "special" is their resistance to higher torque loads by virtue of their design, materials, and surface treatments.

Best,

Dan.

Andre Jute

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A good blueprint Rohloff chainline, built by a conscientious OEM or a competent DIYer, is in any event straight to within 1mm, so I wouldn't worry overly much about that, though it does no harm to check. (To reduce errors and avoid marking the seat tube centre, measure from the far side of the seat tube to the outside of the chainring, then subtract half the seat tube diameter and also half the chainring thickness. At the rear measure from the far side of the non-power side hub flange to the outside of the sprocket and do the math in a like manner.)

I have the highest respect for KMC's chain engineering. But my standard first series Rohloff sprocket has already done 10K+ on the first side without showing much sign of wear, about half of that with a bottom bracket motor, and virtually no wear on the steel chainring either, and very economical use (compared to my history as a chain wrecker) of KMC's attractively priced X8-9x derailleur chains (because in bulk they're cheap from my supplier) so one has to hope KMC's 10K guarantee for a complete 3-unit drivetrain is very conservative, because any changeover is likely to be expensive unless the rider wears out his old sprocket, chain and chainring all at once. I expect that KMC is aiming the complete drivetrain set at OEMs.

Another note: the most popular aftermarket electric motor installation is Bafang's 8FUN bottom bracket motor, and that is so wide that a reasonable chainline can only be achieved by using a dished chainring. The Hebie in its current specs and styling fits at least one of the tooth-count options on Bafang's in-house chainrings.

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Now we come to the meat of the matter: Will Hebie make a Chainglider to fit the 1/8in wide chain and associated sprocket and chainring? After considerable experience of the Chainglider, and on mature consideration of my priorities  -- concluding that clean cuffs on my pants and zero chain service are more important than sporting the latest fashion from KMC, I've decided that anything that doesn't fit the Chainglider doesn't go on my bike.

Personally, and professionally too if Hebie were to retain me as their marketing consultant, I'd say that KMC is so big and so thoroughly integrated into the OEMs, and electric bikes are going to be so big, that Hebie would be foolish to be left out. However, we have plenty of reported experience here of Hebie apparently not knowing their market and even their products too well.

The minute there is a suitable Chainglider, we can talk again.

There's a small doubt left. As you can see passim on this forum, those members who took one for the group by fitting the more expensive stainless KMC chain have not (yet?)reported vastly greater mileages than on the more common KMC chains. And nor has the X8-9x KMC chain used with a high-torque motor cut into my mileage: on the contrary, the KMC X8-9x, even used with a motor, has almost tripled my chain mileage when compared (unfairly perhaps) with the Shimano Nexus chains I used before. In short, is this new KMC drive system the answer to a question that no-one has had reason to ask? Thus the same reasoning that caused me to skip the KMC stainless chain may lead me to skip this innovation from KMC as well.

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Love hearing about new bike engineering. We're fortunate to live in interesting times, and to the Devil with the relevant Chinese curse.

John Saxby

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I've decided that anything that doesn't fit the Chainglider doesn't go on my bike.

+1 -- transAtlantic consensus-in-the-making on this one.

mickeg

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Thanks for posting, it is always nice to know what the latest options are.

I will keep using the cheapest KMC chains, I have several sitting on the shelf.  Occasionally when i have ordered something on line I needed a minimum order to get free shipping, then expendables like chains or cables get added to my order.

My last tour, almost a thousand miles (~~1500 km) I was sure would wear out my chain, I had been using that chain for some time before the trip, I was surprised when I got home that my tour did not finish it off.  It was quite rusty from the frequent rain, but still within elongation specs.