Bafang BBS02B (which chainring)

K

Kapper911

New Member
Region
Europe
Hi,
I just bought a new grand canyon mtb
I planning to install a Bafang BBS02B Mid Drive motor on it.
My mtb has shimano Deore, 12-speed (10-51)
I'm a little in doubt which chainring I shall choose. I think the range is 42 to 52.
i'm only going to use it on normal road to work, no offroad, dirtroad, or steep hills.
Which chainring size will you recommend for my setup?
Thanks,
Kasper Denmark
 
Kapper911 said:
Hi,
I just bought a new grand canyon mtb
I planning to install a Bafang BBS02B Mid Drive motor on it.
My mtb has shimano Deore, 12-speed (10-51)
I'm a little in doubt which chainring I shall choose. I think the range is 42 to 52.
i'm only going to use it on normal road to work, no offroad, dirtroad, or steep hills.
Which chainring size will you recommend for my setup?
Thanks,
Kasper Denmark
Click to expand...
For reference.. I mostly ride paved rail trails with a fair amount of hills and I've tried the 44t and 46t with my 7sp (13-28) and I prefer the 46t.
I think with your rear spread you can make anything work.
 
rocket...I've been having a blast with the BBSHD on my SC Nomad lately, and I'm considering a BBS02 for another build. This chainring/chainline issue is of interest to me. I had to use the Luna Eclipse 42T for my BBSHD on the 73mm BB on the Santa Cruz, and it achieved a factory chainline with this component. I've done some reading and trying to see internet picture detail on the chainline and chainring options for the BBS02 in a mountain bike application but haven't found what I was looking for.

From seeing parts options for the BBS02 like these adapters for 104 chainrings, can I assume the 02 doesn't have the chainline issue of the HD? Apparently the drive sits closer into the frame, correct? My application will be on a 68mm BB full suspension MTB, and I'm guessing I can run one of these 104 chainring adapters and run a good, 30'ish tooth chainring but still have good chainline. There's no opportunity to see a BBS02 in the flesh around here, and I haven't see a good enough picture of one with one of these 104 adapters to be sure. Can you or any other forum member confirm this?
 
TNC said:
rocket...I've been having a blast with the BBSHD on my SC Nomad lately, and I'm considering a BBS02 for another build. This chainring/chainline issue is of interest to me. I had to use the Luna Eclipse 42T for my BBSHD on the 73mm BB on the Santa Cruz, and it achieved a factory chainline with this component. I've done some reading and trying to see internet picture detail on the chainline and chainring options for the BBS02 in a mountain bike application but haven't found what I was looking for.

From seeing parts options for the BBS02 like these adapters for 104 chainrings, can I assume the 02 doesn't have the chainline issue of the HD? Apparently the drive sits closer into the frame, correct? My application will be on a 68mm BB full suspension MTB, and I'm guessing I can run one of these 104 chainring adapters and run a good, 30'ish tooth chainring but still have good chainline. There's no opportunity to see a BBS02 in the flesh around here, and I haven't see a good enough picture of one with one of these 104 adapters to be sure. Can you or any other forum member confirm this?
Click to expand...
With the stock Bafang chainring on a fsmtb w/68mm bb my chainline was dead center of a 7sp. The stock ring I believe has a 5mm offset towards the motor.
IMG_20210609_154456_287.JPG
So on a 68mm bb the chainline with the stock rings are 50mm from the center of the bike. (reference first # of D and F)
IMG_20210609_160225_950.JPG

Those 104 adapters are flat and won't work without spacers behind them as the chainring bolts hit the plastic gear housing. I think you need to add 1-2mm but it still leaves the ring much further out.
IMG_20210609_154426_666.JPG
If you mount the ring on the outside of the 104, it puts the ring about 13mm out from the stock ring.
IMG_20210609_154344_268.JPG

In my opinion... The only other ring that might work is one of the expensive Lekkie Bling Rings.. But that will probably require spacers as well.
 
Thank you gentlemen for the detailed info. That's disappointing. And apparently there's not a fix like the 42T Luna Eclipse for the BBS02, correct?...only fits the HD? That 42 Luna worked wonders on my Nomad. I was hoping there was a narrower profile on the 02. So in many ways there's not much advantage over the HD.
 
There are errors here, the Lekkie 42T offset is 18.5mm

BBSHD Chainring offset guide - Electricbike.com Ebike Forum

Because of the presence of the motor taking up space, the point where a chainring would mount onto the motor is pushed out to the right from where a chainring would normally be. Offset is defined as how much distance you are able to bring the sprocket closer towards the frame. This results in a...
electricbike.com
 
TNC said:
Thank you gentlemen for the detailed info. That's disappointing. And apparently there's not a fix like the 42T Luna Eclipse for the BBS02, correct?...only fits the HD? That 42 Luna worked wonders on my Nomad. I was hoping there was a narrower profile on the 02. So in many ways there's not much advantage over the HD.
Click to expand...
I think the HD may be easier to work with chainring as there are more adapters and rings already available for it.
The BBS02B is a bit of a stepchild when it comes to this.
That said.. The stock ring was dead on for me.
 
Gionnirocket said:
The BBS02B is a bit of a stepchild when it comes to this.
Click to expand...
Yeah, 02B motor sales are quite slow.(one customer an LBS is convinced the 500W versions are the most reliable) There were Luna eclipse rings for 01 & 02 versions a few years back.
 
One weak spot is the 12-speed. These chains are narrow, so not as robust as a 9-speed. The cogs are also narrower and not as robust. Also even with a Bling Ring you are prone to drop the chain at the front when using low gear. The cross chaining will be too great. You might consider popping on a 9-speed cassette, shifter and derailleur.
 
tomjasz said:
Yeah, 02B motor sales are quite slow.(one customer an LBS is convinced the 500W versions are the most reliable) There were Luna eclipse rings for 01 & 02 versions a few years back.
Click to expand...
Funny thing is... When I first did the install, I did it with a pretty worn chain and freewheel... Not a single chain drop.
A few months in when the chain was done, I changed it along with the chainring and freewheel... Of course then I started getting drops in the lowest gear so I searched around for options. After realizing there was much that would easily work in my preferred 44t - 46t ring I diy'd a chain guide. After about 2 months I noticed I was getting a little bit of chain gurgle and thought it might be my guide so I removed it. Still got a bit of gurgle but the chain no longer drops. It's as if it prefers worn chains 🤣
If I boeshield the chain every 100mi..the gurgle is hardly noticeable. Son na ma bitch!
PedalUma said:
One weak spot is the 12-speed. These chains are narrow, so not as robust as a 9-speed. The cogs are also narrower and not as robust. Also even with a Bling Ring you are prone to drop the chain at the front when using low gear. The cross chaining will be too great. You might consider popping on a 9-speed cassette, shifter and derailleur.
Click to expand...
I concur.
I started shopping for next spring and the Frey CC is a consideration. First thing I asked was.. what are my options below 10sp.
 
tomjasz said:
I found the 42T Lekkie if you want to try it. It would cost you the price of first class postage to return. It’s an ugly gold. If not I’ll put it up for sale.
Click to expand...
Much thanks Santo Bafango 🌟 😇 🌟
But I think the 44t - 46t world is where I prefer. Also the offset on that ring is greater than stock so I'd end up having to go with spacers. Not the end of the world.. but I think I'm satisfied with where I am. I went with the next level up on the KMC chain for the next replacement so I'll see if that solves the gurgling.... or perhaps I'll just run (stretch) the current one long enough that it is quite like the original install was 🙃
 
tomjasz said:
I f

I found the 42T Lekkie if you want to try it. It would cost you the price of first class postage to return. It’s an ugly gold. If not I’ll put it up for sale.
Click to expand...
I got ambitious and have been feeling stronger with the nice weather we've been having so I swapped out the 44t back to the 46t. Gurgle gone!
I first thought it was the new chain, but it seems the 44t ring was either defective or a poorly executed knockoff. I couldn't see anything wrong with it and the teeth spacing looked to be exactly as the 46t... but the 46t is quiet and marginally smoother when pushing it hard.
 
Gionnirocket said:
I got ambitious and have been feeling stronger with the nice weather we've been having so I swapped out the 44t back to the 46t. Gurgle gone!
I first thought it was the new chain, but it seems the 44t ring was either defective or a poorly executed knockoff. I couldn't see anything wrong with it and the teeth spacing looked to be exactly as the 46t... but the 46t is quiet and marginally smoother when pushing it hard.
Click to expand...
Confirming question: This is a narrow wide 46-t Biling Ring? Glad to hear of the improvement.
 
PedalUma said:
Confirming question: This is a narrow wide 46-t Biling Ring? Glad to hear of the improvement.
Click to expand...
Nope... Both Bafang rings as the 5mm offset lines up perfectly with my rear gearset.
I believe that the Lekkie would require 4mm of spacers to maintain the same. Screenshot_20210617-143437.png
 
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