Bafang Ultra Recommended Chain

[m@Robertson]

For long term reliability, you want to have many things in order. Do your build right and you will have long life on your drivetrain without the issues a lot of people have. My Bullitt came into use in March, and just crossed 1000 miles. It has no sign of chain, chainring, cog or cassette body wear. It has an 11 spd drivetrain. My Surly Big Fat Dummy is a monster of a bike and it is about to cross 1500 miles since mid-July of 2020. Almost the same 11 spd drivetrain. Same deal with no signs of visible wear yet. That bike is a longtail and has two chains totalling somewhere around 210 links.

In addition to choosing the right hardware, chainring alignment is a HUGE deal to preventing the chain from buzz sawing through a chainring and cogs. You don't have as many options with an Ultra but you do still have some. In particular the Christini front 104 BCD adapter.

On my 1750w BBSHDs, years ago I started out running Micro Shift or Shimano shifters and a Shimano RD-M591 long cage derailleur. Couple that to a narrow-wide front chainring of good quality, a 1-piece steel rear cluster and underneath a steel cassette body with strong pawls - preferably a 16T-32T ratchet mech of the type found on DT Swiss or ZTTO hubs (also SunRingle of the kind WattWagons is using on their Ultra builds). I topped it off with a KMC e9 chain. I did I think 3 of these. A KMC 'e' chain lasts about 3000 miles on one of those I've found.

Beginning in early 2020, after hearing a lot about how the narrower chains are actually stronger over time in the DIY community, I went to building 11 speed bikes. SRAM GX and NX, with Sunrace CSMS7 clusters (all steel cogs and framework), KMC e11 chains and DT Big Ride or Hybrid hubs, with a steel cassette upgrade on the former (steel is included on the 350 Hybrids). Two of those so far and I described both above. I'll stick with 11s based on my experience thus far. Note the Sunrace CSMX8 is also a good steel 11s cluster despite its alloy framework. My trail wheels for my BFD use one and its been fine.

I also have an eMTB I built with tool steel SRAM EX1 mid drive cluster and derailleur, with a SRAM EX-1 chain (its an 8 spd cluster and chain is 10 spd sized) powered by a roughly 2600w Cyc X1. It all works fine together but I don't have enough miles on the bike to say anything about longevity.

I have never broken a single chain across my entire mid drive 'fleet' and years of daily riding. As I said, I change my 9 spd mids' chains at 3000 miles (along with the whole rear cluster, since I use cheap, 1-pc steel units).

I have not found 11 spd drivetrains to be in any way a detriment. While I primarily pedal, I am not shy about laying in full throttle and flogging the beast. I will say a KMC e11 is priced as if it were being held for ransom. I just snagged a replacement CSMS7 for the eventual day when I wear one of mine out. Cost me $75+ shipping. 9 speed is far cheaper, with an HG400 cluster running about $25-$30 and an e9 being quite a bit cheaper as well. BUT I have come to really appreciate the extra available gears on my cargo bikes, especially the BFD that also sees trail use when I cut the bags off and go and climb hills with it. You can't get all 11 speeds if you are smart about how far you choose to let the chain misalign, but you can get at least 2 more than you could with a 9 spd (1 more up and 1 more down).

In addition to properly designing the drivetrain's alignment and choosing components that are strong enough for the job, riding a mid drive intelligently is the other key ingredient to not having worries about a high powered motor tearing things up. Anyone can jump onto a hub bike and know how to ride it. A mid has a learning curve that - without an instruction book - may never be climbed, with worn out parts the result.

How To Ride a Mid Drive Ebike Without Breaking It

If you can ride a bicycle you already know how to ride a hub drive ebike. Not so a mid drive. Particularly a powerful one that can tear your chain apart. Fear not. The rules are simple.

talesontwowheels.com

 

[jkvt]

Yeah, you know that's a good point about the chainring alignment. It's a big enough deal on regular bikes. I guess we'll see how this goes. I think I won't be cheap on the chain and I'll just be sure to maintain it and see if I can get some life from the 10 speed setup. I'll also see how the 44T chainring that comes with this goes. Again, a lot of the riding is going to be on road. I may bump up the chain ring slightly so I can use more of the middle of the cassette. I read somewhere not to go too high though so you don't heat up the motor on hills. Something like 46 or 48T chainring (max) should be good to keep at upper teens/low 20s mph on the road without using the highest gears. I really don't know how big the largest cog is going to be on the cassette so that might be a deciding factor, at least for the short term. I know with my current bike, on an 8 speed setup, I'm at around 6th going 16-17mph. That's with a 42T chainring.

 

[m@Robertson]

Yeah, you know that's a good point about the chainring alignment. It's a big enough deal on regular bikes. I guess we'll see how this goes. I think I won't be cheap on the chain and I'll just be sure to maintain it and see if I can get some life from the 10 speed setup. I'll also see how the 44T chainring that comes with this goes. Again, a lot of the riding is going to be on road. I may bump up the chain ring slightly so I can use more of the middle of the cassette. I read somewhere not to go too high though so you don't heat up the motor on hills. Something like 46 or 48T chainring (max) should be good to keep at upper teens/low 20s mph on the road without using the highest gears. I really don't know how big the largest cog is going to be on the cassette so that might be a deciding factor, at least for the short term. I know with my current bike, on an 8 speed setup, I'm at around 6th going 16-17mph. That's with a 42T chainring.

Well give it a try first and see where you are. I weigh 250 if I am lying or have skipped breakfast and lunch, and 260 otherwise. I have no problem getting a 160 Nm BBSHD running 30a and a 52v battery up to 30 mph with a 42T front ring, and on top of that I should stay off the 12T ring as it bogs the motor. A 13T gets to the same speed faster.

Thats something you need to spend some time fiddling with. Don't expect to get it right the first time. A 42x11 could be plenty for you unless alignment is off and you need to move inboard, so then and only then should you step up to say a 46 or a 48... because now you are on an 18 or 20 out back. Keep that sucker spinning.

 

[PedalUma]

I respect @m@Robertson's experience. Gotta love the BFD. I still think that the most cost effective way to go is a seven-speed with a long cage and a wide range of gears. My go to bike happens to be a three-speed. With a mid-drive I find that the power means that having many gears is not as needed when I can just adjust power levels. This has been a great discussion. And we have provided @jkvt solid information. Go Team EBR!

 

[jkvt]

Yeah, thanks very much. I appreciate all the help. I agree I'll need to play with it and am probably just overthinking something now that will just be easier to figure out more definitively once the bike gets here, which can't be soon enough. Lots of great tips here though from everyone so thanks again!

 

[jkvt]

btw, @m@Robertson, I just got around to reading your talentontwowheels post. Super helpful Thanks much!

 

[m@Robertson]

I respect @m@Robertson's experience. Gotta love the BFD. I still think that the most cost effective way to go is a seven-speed with a long cage and a wide range of gears. My go to bike happens to be a three-speed. With a mid-drive I find that the power means that having many gears is not as needed when I can just adjust power levels. This has been a great discussion. And we have provided @jkvt solid information. Go Team EBR!

Thx for that!
I do want to say the easier build is 9-speed. The HG400 cluster is a true 1-piece and despite its price going way up in recent times is still $39 or so. The RD-M591 Shimano is a great derailleur and inexpensive as well. My 9spd hub motor'd commuter used a SRAM X.5 which I am just as happy with, and the SRAM shifters take up less real estate on the bars for more flexibility on where you put your throttle. An X.5 is on EBay right now for under $50 with a shifter for $19.99... so once again 9spd is a hell of a lot cheaper.

 

[Mike Burns]

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!

I built a BBSHD 26" fat bike running at around 2000 watts using a SRAM XX1 chain ($46-$51 for an 11-speed), the bike's original SRAM 10-48 cassette and Lekki 42-tooth front and so far the chain looks as it will easily last over 2000 miles before seeing .5% wear. I suspect the cassette will wear out first. I use the same chains on my pedal bikes and they shift beautifully and last forever.

 

[tomjasz]

I built a BBSHD 26"

Connex “ebike chain” on mine.

 

[PedalUma]

I take it down to nine from 11 and use a wider chain. Small increments do not matter much when you have power. Same range. Being robust matters more with power.

 

[mxer]

I run a Shimano E6090 ebike chain on my ultra, 10 speed no issues a year in

 

[TPEHAK]

Has anyone tried single speed Izumi Chain V Super Toughness Track Chain (3/32" or 1/8") with internal gear hub?

https://www.amazon.com/Izumi-Chain-Super-Toughness-Track/dp/B07YZSPBKN

https://www.amazon.com/Izumi-Chain-Super-Toughness-Black/dp/B00BGDSWYG/ref=sr_1_3?crid=2T77QJG3CCJN8&keywords=Izumi+Super+Toughness+3%2F32&qid=1686161022&sprefix=izumi+super+toughness+3%2F32%2Caps%2C135&sr=8-3#customerReviews

My 3000W Innotrace X1 destroyed KMC X8 chain pretty fast (deformed and cut off the rollers withing a few rides!). I know KMC X series chains are not the most durable KMC chains (KMC has more durable like e1, e101, e8, e10 etc) but that Izumi Super Toughness Track chain is about 3 times more expensive than the most durable KMC chains so I am wondering if this price reflects the lifespan under high power. It looks like a reviewer on Amazon uses such chain with 8000W motor without issues!

 

[smorgasbord]

FWIW, the SRAM X01 12-speed chains on our two Ultra powered bikes are doing very well after over 2k miles. I’ve posted the actual stretch in another thread if you’re interested.
That chain came out on top on a pretty in depth test some years ago, even compared to 12 speed chains. I know most people don’t have 12 speeds, though.

 

[TPEHAK]

I think if you deal with high torque mid drive motors like Bafang Innotrace X1 the only option is to use heavy duty single speed chain with gear hub.

KMC eCargo1 EPT also cached my attention. They claim it has "diamond durability" rating and 50% higher tensile strength comparing with industry standard

eCargo1 EPT- KMC

www.kmcchain.com

Anybody tried it? For some reason I can not find this chain for sale.

 

[smorgasbord]

Just to expand with details on my previous post:

1 From this post:

Two bikes with same chain/mileage and the worst is 0.16% stretch, with 0.5% being the Park Tool advice for replacement, so at this rate I've got another 4k miles to go, for 6k total (maybe). Don't ride much in the rain, never in mud.

2. From this 2019 Dec Chain Wear Test:
For 11-speed chains:

Wippermann Connex SX, Wippermann Connex SB, SRAM XX1 Hard Chrome and YBN E-bike as being the 11-speed kings of durability in terms of resistance to elongation wear (take note, the elongation wear qualifier is important, which I’ll soon cover). Coming in just behind, and reaching the .5% wear mark at near 3,000 km were the Shimano Dura-Ace (HG-901), YBN SLA Gold, Campagnolo Chorus, Campagnolo Record, and YBN Anti Corrosion.

For 12-speed chains:

Shimano’s new XTR 12-speed chain proved to be outstanding in this regard and aligns perfectly with what Shimano claims as far as improved durability. However, and as Kerin points out, the new chains feature a totally new plate shaping that’s designed to improve shift performance, but in turn, makes it a poor fit for other drivetrains.

...the results of SRAM’s high-end Eagle chains are simply mind-blowing. The top-tier X01 and XX1 Eagle chains both beat Kerin’s 5,000 km test and only recorded 70% of the allowed elongation wear at the time of doing so. Extrapolated out, these chains would likely have hit 7,000 km with the terrible control chain lube. They’re so durable, in fact, that they had started to wear through the cogs from pure abrasion before measuring as worn. Keep in mind that the control lubricant was intentionally abrasive, and so you can expect great life from your SRAM Eagle drivetrain if you keep it clean.

“SRAM claim the world’s longest-lasting chain with their XX1, and they are not kidding,” Kerin said. “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.”

Interestingly, they also tested 8, 9, and 10 speed chains and found that the 11 and 12 speed chains were MORE durable!

It seems that with each gear added, durability has improved. And at least for Shimano chains, 10-speed saw a significant jump in durability from 9- and 8-speed, and Shimano’s latest 12-speed XTR mountain bike chain rules the roost as Shimano’s most durable offering.

So it would seem the conventional wisdom that the wider the chain the stronger it is. This testing indicates that newer chain materials/designs win out over raw width (which in actuality only makes the rollers longer, not the walls thicker).

 

[TPEHAK]

I found that my Bafang starts destroying the chain before it is even stretched up to the 0.5 wear mark. What basically happens is it has so much torque it crushes the rollers of the chain. The chain is still fine according to the chain checker, but the rollers look deformed (squished) after just a few rides. It squishes the rollers so much that the rollers start to spread the links walls causing stiff links. And then eventually some rollers just disintegrate from the chain exposing the necks of the links and pins. No matter how clean and lubricated you keep the chain, it is purely mechanical pressure between the parts and the sprocket teeth just cut into the chain rollers.

I guess at such high torque abrasion becomes the minor factor and the major factor is mechanical yield of the material.

For the eCargo1 EPT chain they mention about increased tensile strength. I am not sure if it translates to higher compression strength of the rollers but those rollers should have higher compression strength comparing with regular chain rollers to be able to withstand higher forces of high torque motors.

 

[AHicks]

I found that my Bafang starts destroying the chain before it is even stretched up to the 0.5 wear mark. What basically happens is it has so much torque it crushes the rollers of the chain. The chain is still fine according to the chain checker, but the rollers look deformed (squished) after just a few rides. It squishes the rollers so much that the rollers start to spread the links walls causing stiff links. And then eventually some rollers just disintegrate from the chain exposing the necks of the links and pins. No matter how clean and lubricated you keep the chain, it is purely mechanical pressure between the parts and the sprocket teeth just cut into the chain rollers.

I guess at such high torque abrasion becomes the minor factor and the major factor is mechanical yield of the material.

For the eCargo1 EPT chain they mention about increased tensile strength. I am not sure if it translates to higher compression strength of the rollers but those rollers should have higher compression strength comparing with regular chain rollers to be able to withstand higher forces of high torque motors.

Curious the percentage of time you are spending with the chain on an 11 or 12 tooth rear cluster gear? I found myself on the 11t too often, and not wanting to cause any more wear than necessary, installed a larger front gear. This move allowed me to maintain the same speed as before, while avoiding that 11t that's so well known for causing high amounts of wear. It's still there if I want/need it, but now rarely used....

 

[smorgasbord]

It’s a good idea, with the hopefully obvious caveat that if you currently use your lowest gear a lot, that gear will also become higher. If you make this change, do it before you install a new chain as it probably will need to be longer than your old one for optimum shifting.

 

[AHicks]

It’s a good idea, with the hopefully obvious caveat that if you currently use your lowest gear a lot, that gear will also become higher. If you make this change, do it before you install a new chain as it probably will need to be longer than your old one for optimum shifting.

While there is certainly that chance, there's nothing written in stone. I've done this (larger front gear) on a couple of bikes now, and a buddy has done the same, while using the original chain length. Still shifting just fine. Agreed though, the need for a little longer chain is something to keep in mind when making this move.

 

[TPEHAK]

Curious the percentage of time you are spending with the chain on an 11 or 12 tooth rear cluster gear? I found myself on the 11t too often, and not wanting to cause any more wear than necessary, installed a larger front gear. This move allowed me to maintain the same speed as before, while avoiding that 11t that's so well known for causing high amounts of wear. It's still there if I want/need it, but now rarely used....

I use 44T standard Bafang steel chainring (the biggest the frame allows) and 14T Shimano steel 3/32" cog. I could use bigger cog but that would increase the stress on the gear hub I would like to avoid because of the gear hub is the most expensive part of the drivetrain.