Bafang Ultra Recommended Chain

jkvt

Active Member
Hello,

I have a custom fat bike with a Bafang Ultra that should be coming in early this fall. I have a hub drive MTB now and read a lot about the drivetrain wear with mid-drive, let alone the higher powered Bafang Ultra powered system. Does anyone have a recommendation for a chain? I typically use the KMC X8 on the hub drive, but I'm not sure if that will be strong enough for the new bike (which would actually use an X10, if I stayed in with the same chain model). If usage matters, I expect to use this some on trails, but largely as a car replacement in the winter (not looking to get into this discussion here, but setting it to max of 750w nominal, by way of max speed on the dpc18, keeps it good enough for the streets around here). It may become a year round car replacement though depending on a few things. Oh, there's a shift sensor also. I actually used a friend's BBSHD powered conversion, with a shift sensor, and how that performed has me more optimistic on how long the drivetrain will last, but I could be wrong there. Thanks for any help!
 

greeno

Well-Known Member
Region
USA
City
San Diego
KMC makes a great e-bike chain IMO. I have an 11spd drivetrain and use the KMC E10 chain and have had great luck with it.
 

theemartymac

Well-Known Member
I put the KMC E9 on my bike 1000kms ago, and it's less than .5 wear. I have no concerns about the strength as I have definitely been putting plenty of sustained power through it and I'm a 300lb guy.
 

PedalUma

Well-Known Member
Region
USA
I updated a new Ultra Sondors recently for a friend and it sold yesterday. The buyer drove 400 miles to get it. Then 400 back. I do not recommend a ten-speed drivetrain for powerful motors. The chains and cogs are in my opinion too narrow. It is a stiletto narrow focus of pressure. And replacement parts are expensive. Yet, I do understand the cool factor of a ten-speed. If it were mine I would remove the ten-speed drivetrain components before riding the bike to trade or sell them. I would then install a less expensive and more robust eight-speed or nine. Plan on replacing chains and cassettes regularly on your bike.
The Sondors was a seven-speed with a Tourney twist shifter. I installed a Micro Shift push-push trigger, long cage derailleur, nickel-plated 10-34 freewheel and an X-8 chain. The original chain and gear cluster were toast by 300 miles. This is a powerful motor. My friend wants me to build a custom gravel bike for him next that has a lighter weight torque sensing motor.
 

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smorgasbord

Well-Known Member
Region
USA
First question is how many cogs are going to be in the rear cassette? Cog spacing is dependent on number of cogs, and chain width is dependent on cog spacing.

I believe it's a fallacy that wider chains are always stronger. Typically, the side plates of chains are all the same thickness, so all that's changing is the pin length, and if anything, shorter pins should be stronger.

Here's a review of different chains: https://cyclingtips.com/2019/12/the-best-bicycle-chain-durability-and-efficiency-tested/ Note that it confirms that since 11 speed chains were developed later than 10 speed chains, improvements in materials and hardening processes often mean that some 11 speed chains last longer than 10 speeds chains. And some 12 speed chains last the longest of all, particularly SRAM's X01 and XX1 12-speed chains:

“Both the X01 and XX1 chains were so far ahead of any other chain from a pure elongation wear measure that I had to re-run the tests. The results were basically identical. Their longevity is phenomenal.”

That article also rates chains on efficiency, which is a difference factor than durabilty. For eBikes, durability is more important, IMO.
 

PedalUma

Well-Known Member
Region
USA
I have 8, 9, e10 and e11 chains in my hand. e11 has thinner side plates than the e10. e10 has thinner side plates then the nine. Eight-speeds have cogs that are wider than nine-speeds. The big factor in my view is not the 'strength' of a chain on a bench test. It is the dispersion of force or the concentration of it when ridding for many miles. Cogs that are wide will last longer than thinner ones. This is one reason that I like to run half-link Extra Wide chains on internally geared hubs with wide cogs. Wider rollers have less internal wear per mile so the chains and cogs last longer.
 

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TForan

Well-Known Member
I would just plan on replacing the chain and gear set every 800-1000 miles. It's what I do. I have a nine speed Biktrix Ultra .
 
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PedalUma

Well-Known Member
Region
USA
Good plan. On my nine-speed bike I get two chain changes per cassette. I will guess at that same 1,000 mile mark, changing chains at .05. It is a delimited 350W nominal torque sensor now with peaks at 820W for climbs. I initially had a HD on it with an 11-sp. But that was no fun after the initial 100W thrill and way too heavy. It ate the drivetrain in three weeks. Now I can run with a three-pound battery because I have dropped the build weight.
 

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greeno

Well-Known Member
Region
USA
City
San Diego
FWIW I was told by a "very knowledgable Team Bike Mechanic", aka wrench that the newer 3/32" chains were stronger than the 1/8" single speed chains that some people swear by. A friend of mine had a 3/32" Titanium chain that was worthless but steel is reel in my book.
 

jkvt

Active Member
This is all great feedback. Thanks very much. So it sounds like people here are happy with the e10 chain. Interestingly, on that website you posted, @smorgasbord, it looks to me that the SRAM chains may provide some good value. Extrapolating this to a 10 speed, it seems like the SRAM 1031 might be good for the price. Seems like it comes in as a pretty mediocre chain, as for durability, but cost per 10k km is low. I'm thinking maybe, when the time comes to change the chain, it may be worth trying the SRAM 1031 first to see how it goes.. see if it's strong enough to hold up to this motor. If it doesn't work maybe go towards the more expensive KMC e10?

Anyone know about the SRAM EX1 chain? A lot of sites say its an 8 speed chain with 10 speed spacing. The SRAM site seems to suggest it's a 10 speed chain though? https://www.sram.com/en/sram/models/cn-ex-1-a1
 

TomD

Well-Known Member
I believe my Frey CC came with a KMC chain. Have more than 2K miles and my chain checker still indicates the chain is fine (not even dropping into the first wear slot). That said I suspect it has more to do with my style of riding and keeping things clean and lubricated than brand.
 

PedalUma

Well-Known Member
Region
USA
The EX-1 is for 10-Sp mountain bikes with 250W nominal that are spikey for technical trails. It comes in some longer chain stay lengths or for big cogs. The price is fair.
 

smorgasbord

Well-Known Member
Region
USA
This is all great feedback. Thanks very much. So it sounds like people here are happy with the e10 chain. Interestingly, on that website you posted, @smorgasbord, it looks to me that the SRAM chains may provide some good value. Extrapolating this to a 10 speed, it seems like the SRAM 1031 might be good for the price.
As the article indicates, it's not all SRAM chains that come in with superior durability ratings, not even all the SRAM Eagle chains. So, I don't think you can extrapolate from their high-end 12-speed Eagle chains (X01 and XX1). I use the X01 on my SRAM Eagle GX drivetrain, btw.

Seems like it comes in as a pretty mediocre chain, as for durability, but cost per 10k km is low. I'm thinking maybe, when the time comes to change the chain, it may be worth trying the SRAM 1031 first to see how it goes.. see if it's strong enough to hold up to this motor. If it doesn't work maybe go towards the more expensive KMC e10?

Anyone know about the SRAM EX1 chain? A lot of sites say its an 8 speed chain with 10 speed spacing. The SRAM site seems to suggest it's a 10 speed chain though? https://www.sram.com/en/sram/models/cn-ex-1-a1
The EX-1 chain is part of SRAM's 8-speed system which they say they've designed for e-MTBs with Bosch Gen 3 motors: https://www.sram.com/en/sram/mountain/series/ex1

I don't know if it's truly compatible with 10-speed gearing or not.
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
I've mentioned this before. Knowing the torque available from that Ultra, and it's willingness to pull strong at low rpm, I'd much rather have something like a 7 speed if I thought it would be more durable. IMHO, the 9+ speed drive trains are major overkill. We're talking about an electric motor here. It's not like you need to focus on a keeping the motor within a tiny power band to make power - unless it's about your cadence. That would be a level of riding I don't have to worry about at my size and age.
 

jkvt

Active Member
I believe my Frey CC came with a KMC chain. Have more than 2K miles and my chain checker still indicates the chain is fine (not even dropping into the first wear slot). That said I suspect it has more to do with my style of riding and keeping things clean and lubricated than brand.
This is really good to know. I'll keep the drivetrain in good shape and see how that goes. If I can pull off 2k miles on a chain, I'd be more than happy.

As the article indicates, it's not all SRAM chains that come in with superior durability ratings, not even all the SRAM Eagle chains.
Yeah, I guess I was looking at some of the less expensive ones as showing up as mid-range durability in one of the charts and also low cost per 10,000km in another so I figured they might not be the most durable but strictly looking at cost per mile they could be worth it.

've mentioned this before. Knowing the torque available from that Ultra, and it's willingness to pull strong at low rpm, I'd much rather have something like a 7 speed if I thought it would be more durable. IMHO, the 9+ speed drive trains are major overkill.
I tend to agree, but, I think with more gears you can find a gear where you are more naturally pedaling *with* the motor so everything is just more efficient and you get more range. At least this seems to be how it works with hub motor bikes. Maybe it's different with mid drive. That said, it may not be worth a potentially weaker drivetrain.
 

TomD

Well-Known Member
I've mentioned this before. Knowing the torque available from that Ultra, and it's willingness to pull strong at low rpm, I'd much rather have something like a 7 speed if I thought it would be more durable. IMHO, the 9+ speed drive trains are major overkill. We're talking about an electric motor here. It's not like you need to focus on a keeping the motor within a tiny power band to make power - unless it's about your cadence. That would be a level of riding I don't have to worry about at my size and age.
I've used every gear on mine. Granny gear can be useful when the battery is almost dead or exhibits voltage sag under load and the controller is nannying you to < 250W up the hill to get home.
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
This is really good to know. I'll keep the drivetrain in good shape and see how that goes. If I can pull off 2k miles on a chain, I'd be more than happy.


Yeah, I guess I was looking at some of the less expensive ones as showing up as mid-range durability in one of the charts and also low cost per 10,000km in another so I figured they might not be the most durable but strictly looking at cost per mile they could be worth it.


I tend to agree, but, I think with more gears you can find a gear where you are more naturally pedaling *with* the motor so everything is just more efficient and you get more range. At least this seems to be how it works with hub motor bikes. Maybe it's different with mid drive. That said, it may not be worth a potentially weaker drivetrain.
Yes, that's my point exactly. I'm OK with the extra gears, but, if I thought I could cut the use of replacement parts significantly, the next round would be 7 speed. Most of us don't regularly use all of the available ratios we have with 9+ speeds (I use 2nd through 6th most frequently on my 9 speed). With a 7 speed you can play with the ratios (front and rear) to cover your favorite cadence, and while you're at it you could avoid the tiny tall gears that are tough on chain/sprocket wear - like an 11 tooth top gear for example.
I've used every gear on mine. Granny gear can be useful when the battery is almost dead or exhibits voltage sag under load and the controller is nannying you to < 250W up the hill to get home.
This trying to get home on a really low battery scenario is one I try to avoid. It's too hard on my battery for starters, and I just don't need the extra range that doing that may require. My batteries are generally charged before any longer ride, and otherwise when they get down into the 46v range to avoid that exact scenario. That said, I get the fact that we all have different riding habits - and they may have an effect on what you can/can't/have to do.

Bottom line, I believe the number of gears available on a bike may have more to do with sales hype (mine's bigger than yours/ours is bigger/better/faster mind set) rather than coming from a more practical standpoint. That's me though, FWIW. -Al
 

TForan

Well-Known Member
I rarely use anything but the top three gears. I'd be happy with a four speed gear set. When crossing a street, I just bump it up to 5 and go. I probably stress the gears more than necessary but it hasn't been a problem in four years.
 

MartsEbike

Well-Known Member
Region
Other
My Frey EX came with a KMC E11 but I managed to break it..... I'm now using a Wippermann Connex 11SE chain. No complaints so far all works as expected. This is my first connex chain but I have to say the quality is very good.


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