BBS02 blown controller?

If you go big on the front, you REALLY need to know exactly what it is you are doing with gearing, your riding style and your terrain. For example, above, I recommended (STRONGLY) going to a 42T ring, and even mentioned a 40T ring and how thats a better choice in some respects (the motor needs to spin fast, period). But of the many BBSHD builds I have, I've got one with a 52T front ring. BUT I only did that after a lot of analysis on that particular bike, how I ride it and where I ride it.
  • Always table-flat land
  • On that table flat land, I only use three gears. The one I normally use, one upshift and one downshift.
  • I have a specific cadence I want to ride in, and using the 52T, I go 4 cogs in to get that optimal cadence, which gives me dead-straight chain line, and the 4 cogs in means I am using a pretty big cog on the back that doesn't bog the motor.
  • Oh and the bike is a 2wd set up so the front motor kicks in first so again the motor doesn't bog since the mid drive never has to grunt the bike up from a dead stop, and acceleration is a team effort so I don't strain the $hit out of the drivetrain coming up to speed off the line.
Those are a lot of planets that have to line up to allow a 52T ring to be a safe, smart choice. I am moving that bike to my home now (vs. then) which has a lot of hills, and the first thing that has to go is that big chainring in favor of a 42T.
View attachment 15328Gear choices on a bike build usually evolve. There's what you think you need, then what it turns out you really need after some riding. I've been doing it long enough to know in advance of a build... mostly. But that was not always the case.

Hmm now I am a bit scared of my other bike. That also has a 52tooth front chainring. But that bike seems to move very well and I am happy with it actually. But maybe I should go down a bit on that one too before something burns up in there? Is there a way to know the optimum gearing some way or do you only use feel and experience when you decide which size you go for here?

The other bike is not a fatbike, it is a 29inch Scott.
 
The easy answer on front chainring is to do the minimum size of a 42T. This is the very short version of the recommendation and I am ignoring things like chainline considerations. 42T will get you the most offset and is the reason for the typical recommendation. Going to 40T requires a replacement motor cover and the smaller sizes lose you the offset you would otherwise gain from the 42T ring. Chainring offset on a BBS02 is also a lot less than it is on a BBSHD so you aren't gaining anywhere near as much, but you are still gaining needed straighter chainline.
So the smaller I go the less offset between the frontring and the motor? So therefore the chain comes closer in towards the bike at the front? Is that correct? I don't know a lot about offset regarding frontrings so I am just curious.

By the way where is the most important to have a straight chain line on these mid drives? At the outermost sprocket ring and highest gear. Or closest to the wheel on the biggest ring at the back?
 
Hmm now I am a bit scared of my other bike. That also has a 52tooth front chainring. But that bike seems to move very well and I am happy with it actually. But maybe I should go down a bit on that one too before something burns up in there?

It all boils down to you should never lug the motor, and the motor should spin fast. If you pump in electrical energy into a motor, energy that does not go to create motion creates heat instead. If you hang around enough ebike DIY builder fora you are going to hear the same thing over and over again: 52T is too big. Now... as I showed above, if you really think it thru, 52T can be used so long as you know exactly what problems you are creating, and you know you are not going overboard... but thats something almost everyone who tries it who is new to the game is going to get wrong.

Is there a way to know the optimum gearing some way or do you only use feel and experience when you decide which size you go for here?
Knowing about gearing is actually what gets you into this mess :) You are using cycling knowledge of gearing but not adding in the limitations of the motor when trying to use said gearing. Instead you want to under-gear the bike so the motor can spin faster. Then, since you want to ride on pedal assist, you have to modify the motor so it gives you a good pedal assist experience, which a factory motor pretty much does the opposite of. Which brings me to another article link :)


I write these to save on re-typing common questions, and do in depth treatments of same, and you are hitting all the right notes to get one after the other.
So the smaller I go the less offset between the frontring and the motor?
Not exactly but thats a decent rule of thumb to follow. The issue is what happens hen the chainring is smaller than the secondary housing. A big chainring is bigger than the housing, so it can have a big inset since it covers the gear housing just like ... a hat, lets say. The smaller the chainring, the tighter the fit of the hat. Until you size it so small the hat can no longer fit, so the offset you gain has to go bye bye simply because there is no more room to get away with it.

So therefore the chain comes closer in towards the bike at the front? Is that correct? I don't know a lot about offset regarding frontrings so I am just curious.
Yes thats it you have the idea.

Here lookit: See this 28T chainring? See how much smaller it is than the gear housing? Not much offset possible on that puppy.

20240406_180449.jpg


Now here's a 42T ring. Its bigger so it fits over the motor cover (which is one of those special Lekkie covers that allows a 40T to fit). A chainring like this can be inset to cover the motor like a hat and bring chainline in.

20231106_125513.jpg


And... all of this is for a BBSHD. For a BBS02, there is much less 'push-out- of the secondary housing from the frame, so the amount of offset you can get from a BBS02 chainring is a lot less. The principles are all the same, but where I can get 20mm back on a BBSHD ring, the best you are going to get is maybe 8mm. And you will go down from there with the littler rings.

By the way where is the most important to have a straight chain line on these mid drives? At the outermost sprocket ring and highest gear. Or closest to the wheel on the biggest ring at the back?
Neither. You want it dead center in the cluster. That way you have the most chance of using the gears inboard (lower and bigger) or outboard (smaller and higher) without tweaking the bejesus out of the chainline. This image came from Lekkie. They gave me permission to re-use it in one of my articles so I'll link it here. It comes from one of their user manuals.

lekkie_chainline[1].png



But also know that part of your decision process when gearing a bike is to say to yourself: "Self, I will be working up steep hills and on flat land not so much. So I want to bias my chainline further in from the middle so I can get to the bigger cogs. I need the bigger ones more than the little ones."

So if thats your reality when you are planning out your bike, maybe you fiddle with your chainring offset and buy one that gives a little more or a little less offset to better meet your goals. A Deruiz 42T ring has 15mm of offset. A Gustavo 42T has 18.8mm. A Luna Eclipse 42T has about 22.18mm and a Lekkie 40T Pro has just over 22mm. Thats a lot of variation to pick from.
 

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But also know that part of your decision process when gearing a bike is to say to yourself: "Self, I will be working up steep hills and on flat land not so much. So I want to bias my chainline further in from the middle so I can get to the bigger cogs. I need the bigger ones more than the little ones."

So if thats your reality when you are planning out your bike, maybe you fiddle with your chainring offset and buy one that gives a little more or a little less offset to better meet your goals. A Deruiz 42T ring has 15mm of offset. A Gustavo 42T has 18.8mm. A Luna Eclipse 42T has about 22.18mm and a Lekkie 40T Pro has just over 22mm. Thats a lot of variation to pick from.
Hmm my chainline looks like this on the Scott bike. So would not hurt to go down to let's say 46teeth right?

Hard to see on the picture and create the right angle with my s**tty camera :)
 

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Not exactly but thats a decent rule of thumb to follow. The issue is what happens hen the chainring is smaller than the secondary housing. A big chainring is bigger than the housing, so it can have a big inset since it covers the gear housing just like ... a hat, lets say. The smaller the chainring, the tighter the fit of the hat. Until you size it so small the hat can no longer fit, so the offset you gain has to go bye bye simply because there is no more room to get away with it.
This is the hat correct? The green part of the chainring? Which takes the chainline closer in towards the motor, right?
 

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But also know that part of your decision process when gearing a bike is to say to yourself: "Self, I will be working up steep hills and on flat land not so much. So I want to bias my chainline further in from the middle so I can get to the bigger cogs. I need the bigger ones more than the little ones."

So if thats your reality when you are planning out your bike, maybe you fiddle with your chainring offset and buy one that gives a little more or a little less offset to better meet your goals. A Deruiz 42T ring has 15mm of offset. A Gustavo 42T has 18.8mm. A Luna Eclipse 42T has about 22.18mm and a Lekkie 40T Pro has just over 22mm. Thats a lot of variation to pick from.
The offset takes the chain closer in towards the bike, right? Have I understood that correctly?

Which is the best one of these small ones for gaining offset? Lekkie? The gustavo on Ali I find different offsets for them. 2mm for 32-36t and 14mm for the 42-52t.
 
Hard to see on the picture and create the right angle with by s**tty camera :)
To me, it kind of looks like your chain is already angled inward, and it would get worse if you downshift to a bigger cog. Here's a set of pics I did for that same white bike. I took my pics from the back. Left to right they are all the way in (big cog), all the way out and smack in the middle.

20230422_150119.jpg
20230422_150305.jpg
20230422_150428.jpg


I went thru multiple iterations of drivetrain on that bike before I was satisfied with it. Here's a chart comparing the Plan B chainring, which was a Lekkie Pro 40T. Worth noting I originally built this bike as a 9 spd and then, since I had an Advent X drivetrain on a shelf in my shop, switched to that and, once I experienced it for the first time, kept it. Green is good chain line, yellow is acceptable and red is a no-no. These chartsd come from my Bullitt build series on my site.
clusterf[1].png


So once I decided the 10s system was preferred as it gave me more green options, I was still not quite satisfied. I had a Luna Eclipse ring in my parts pile and swapped it in to replace the Lekkie 40T. This is how it shook out
chainring_PlanC[1].jpg


The yellower yellow on the top group means "less acceptable but still barely acceptable" The Luna ring also has longer teeth that makes it hold onto the chain better in bad alignment situations, and since good chain line means more to me on the bigger cogs, thats why I stuck with the Luna.

You don't need to make charts and buy different parts to do the same sort of thinking on your bike build. But this kind of thought should go into the decision process when gearing your bike.

Hmm my chainline looks like this on the Scott bike. So would not hurt to go down to let's say 46teeth right?
Chain line is not what you should be worrying about. Your 52T ring is too big and will damage your motor (and maybe has already done so, albeit probably not permanently). So, forget about offset and focus on shrinking that fokker. Since you own a 44T ring, you can just put it on. Once you change the ring then start concerning yourself with the finer points about whether its fitment can be improved, and what you can buy to do that.

This is the hat correct? The green part of the chainring? Which takes the chainline closer in towards the motor, right?
Yes although that is not much offset to be calling a hat. This is more like it but you can't get this kind of offset on a BBS02

61v6Ys4slgL._AC_SL1000_[1].jpg


The offset takes the chain closer in towards the bike, right? Have I understood that correctly?
Yes. Its called offset but maybe its easier to understand if you call it 'inset'.
Which is the best one of these small ones for gaining offset? Lekkie? The gustavo on Ali I find different offsets for them. 2mm for 32-36t and 14mm for the 42-52t.
Well, more offset is more better. But what if its so much it hits your chainstay? Then you have to put spacers behind the ring to move it back out again, which also means longer bolts and is generally something to avoid if you can. Figuring this all out is part of your individual build process. Worth mentioning: 14mm sounds like a lot for a BBS02 ring. Although I do know the Gustavo 42T ring for the BBSHD is 18.8mm (when measured properly which Ali sellers seldom do) so maybe 14mm is correct.
 
To me, it kind of looks like your chain is already angled inward, and it would get worse if you downshift to a bigger cog. Here's a set of pics I did for that same white bike. I took my pics from the back. Left to right they are all the way in (big cog), all the way out and smack in the middle.

View attachment 15342View attachment 15343View attachment 15344

I went thru multiple iterations of drivetrain on that bike before I was satisfied with it. Here's a chart comparing the Plan B chainring, which was a Lekkie Pro 40T. Worth noting I originally built this bike as a 9 spd and then, since I had an Advent X drivetrain on a shelf in my shop, switched to that and, once I experienced it for the first time, kept it. Green is good chain line, yellow is acceptable and red is a no-no. These chartsd come from my Bullitt build series on my site.
View attachment 15345

So once I decided the 10s system was preferred as it gave me more green options, I was still not quite satisfied. I had a Luna Eclipse ring in my parts pile and swapped it in to replace the Lekkie 40T. This is how it shook out
View attachment 15346

The yellower yellow on the top group means "less acceptable but still barely acceptable" The Luna ring also has longer teeth that makes it hold onto the chain better in bad alignment situations, and since good chain line means more to me on the bigger cogs, thats why I stuck with the Luna.

You don't need to make charts and buy different parts to do the same sort of thinking on your bike build. But this kind of thought should go into the decision process when gearing your bike.


Chain line is not what you should be worrying about. Your 52T ring is too big and will damage your motor (and maybe has already done so, albeit probably not permanently). So, forget about offset and focus on shrinking that fokker. Since you own a 44T ring, you can just put it on. Once you change the ring then start concerning yourself with the finer points about whether its fitment can be improved, and what you can buy to do that.


Yes although that is not much offset to be calling a hat. This is more like it but you can't get this kind of offswet on a BBS02

View attachment 15347


Yes. Its called offset but maybe its easier to understand if you call it 'inset'.

Well, more offset is more better. But what if its so much it hits your chainstay? Then you have to put spacers behind the ring to move it back out again, which also means longer bolts and is generally something to avoid if you can. Figuring this all out is part of your individual build process. Worth mentioning: 14mm sounds like a lot for a BBS02 ring. Although I do know the Gustavo 42T ring for the BBSHD is 18.8mm (when measured properly which Ali sellers seldom do) so maybe 14mm is correct.
Great :) thanks.

What do you think about 44 for the fatbike and 46 for the Scott? I ordered a 46tooth to the Scott as well because I got so paranoid about spinning the motor and stuff :)

But do you think I should go even lower on that bike too? From 46 to 44? That is more of my main bike which I ride in the city to work and stuff. Cruising around kind of. Although there is a lot of hills where I live so pretty often slopes and steep hills also on asfalt.

The fatbike I am also going to open up but waiting for some nylon gears and a clutch before I put my work pants on for that one. So I have some time to brainstorm about different solutions for it. Fatbike is for fishing and things like that.
 
Great :) thanks.

What do you think about 44 for the fatbike and 46 for the Scott? I ordered a 46tooth to the Scott as well because I got so paranoid about spinning the motor and stuff :)

But do you think I should go even lower on that bike too? From 46 to 44? That is more of my main bike which I ride in the city to work and stuff. Cruising around kind of. Although there is a lot of hills where I live so pretty often slopes and steep hills also on asfalt.

The fatbike I am also going to open up but waiting for some nylon gears and a clutch before I put my work pants on for that one. So I have some time to brainstorm about different solutions for it. Fatbike is for fishing and things like that.
Also, I dont find a suitable chain guard for the gustavos. Any idea if there are any? Regarding offset which one of the ones above, that you mentioned, do you prefer yourself? Of the smaller ones I mean. Like 36-40s.
 
Great :) thanks.

What do you think about 44 for the fatbike and 46 for the Scott? I ordered a 46tooth to the Scott as well because I got so paranoid about spinning the motor and stuff :)
I think 44 and 46 are almost certainly too big. 42T is the go-to standard you will hear recommended over and over on DIY build groups for a reason. And 42 is recommended for the much more robust BBSHD. For a BBS02, that is not so strong, and is capable of being fried if you lug it too much, the smaller rings are definitely more highly recommended. And since less than 42 means you lose the offset for the reasons I described above, 42 is not just the max, its the minimum as well.
But do you think I should go even lower on that bike too? From 46 to 44? That is more of my main bike which I ride in the city to work and stuff. Cruising around kind of. Although there is a lot of hills where I live so pretty often slopes and steep hills also on asfalt.
See above. If hills then 42T, compounded by the fact its just a poor little BBS02.

If you want to deviate from that 42T default, you should have specific reasons why, informed by knowledge of the negatives (all of which are equipment related) and knowing that what you are doing will mitigate or erase that. Thats how I came to use a 52T ring. 52T is very bad, but I had an awd bike that really eliminated the motor lugging issue, and I knew I was going to stay in the middle of the cluster and never use the small cogs, which on its own also largely eliminated said lugging.

Get on one of the many DIY and Bafang-specific DIY groups on Facebook with thousands of members each, and you will hear 42T as a mantra. But in a much shorter 2-sentence format thanks to the limitations of the platform.
 
Also, I dont find a suitable chain guard for the gustavos. Any idea if there are any?
I never do chain guards. If I am riding with long pants, which is almost never, I use a velcro cinch strap on my legs. I keep them on the bike wrapped around something so I am never without them even if I seldom use them.
Regarding offset which one of the ones above, that you mentioned, do you prefer yourself? Of the smaller ones I mean. Like 36-40s.
It depends on the bike and the job it does. lets see...

  • On the Big Fat Dummy I have downsized from 46T (Luna Eclipse and 130 BCD adapter with a Wolftooth chainring)) when riding it as a street daily driver, to 42T when it was still a street bike, to 36T Lekkie when it got to dedicated use as a wilderness bike to, now, 28T Lekkie. That bike with its 188-link chain has such long stays that offset is a minimal issue and cadence is the governor there.
  • On the white Bullitt, it started out with a Lekkie HD Pro 40T with the full 22.25mm offset, to the Luna Eclipse 42T.
  • For the green Bullitt, 52T Lekkie but when I get it home from its storage in Fresno, its probably going to get my other Luna Eclipse 42T which is hanging on a wall in my kitchen (yes really I have chainrings as wall decorations).
    20240511_114139[1].jpg
  • For my Mongoose Envoy, which is another longtail with reduced need for offset, I have a Deruiz 42T like I pictured in a previous post. That one measures out to about 15mm offset.
  • For the Stormtrooper and 2Fat, both have Lekkie 42T which has 2mm less offset than the Lekkie Pro 40T
  • The Apostate has a 40T Lekkie (not the Pro version)
  • The Smash has a 36T Wolftooth ring. Or maybe its a 34. Different situation there as its motor is a Cyc X1 Pro that uses a whole different build technique.
  • As a backup I'll use later, I have a Gustavo 42T, and a 130 BCD adapter with a Stone 48T ring that I don't plan on using.
So... there is no such thing as a single favorite. You use what works best for your build after measuring things out and thinking them thru.

20240511_122224-EDIT[1].jpg
 
I never do chain guards. If I am riding with long pants, which is almost never, I use a velcro cinch strap on my legs. I keep them on the bike wrapped around something so I am never without them even if I seldom use them.

It depends on the bike and the job it does. lets see...

  • On the Big Fat Dummy I have downsized from 46T (Luna Eclipse and 130 BCD adapter with a Wolftooth chainring)) when riding it as a street daily driver, to 42T when it was still a street bike, to 36T Lekkie when it got to dedicated use as a wilderness bike to, now, 28T Lekkie. That bike with its 188-link chain has such long stays that offset is a minimal issue and cadence is the governor there.
  • On the white Bullitt, it started out with a Lekkie HD Pro 40T with the full 22.25mm offset, to the Luna Eclipse 42T.
  • For the green Bullitt, 52T Lekkie but when I get it home from its storage in Fresno, its probably going to get my other Luna Eclipse 42T which is hanging on a wall in my kitchen (yes really I have chainrings as wall decorations).
    View attachment 15370
  • For my Mongoose Envoy, which is another longtail with reduced need for offset, I have a Deruiz 42T like I pictured in a previous post. That one measures out to about 15mm offset.
  • For the Stormtrooper and 2Fat, both have Lekkie 42T which has 2mm less offset than the Lekkie Pro 40T
  • The Apostate has a 40T Lekkie (not the Pro version)
  • The Smash has a 36T Wolftooth ring. Or maybe its a 34. Different situation there as its motor is a Cyc X1 Pro that uses a whole different build technique.
  • As a backup I'll use later, I have a Gustavo 42T, and a 130 BCD adapter with a Stone 48T ring that I don't plan on using.
So... there is no such thing as a single favorite. You use what works best for your build after measuring things out and thinking them thru.

View attachment 15369
I have investigated further and it seems the actual offset of the Gustavo 42t is 18mm. Since it is a copy of the Lekkie bling 42t, according to a member on another forum. Do you think this one might suit both of my bikes man? Especially the fatbike perhaps? Since I am going fishing with that one, and I eventually hope to go hunting with it as well. If it works well.

Yeah, where I live chainguards are almost a must :) . Since I live in Scandinavia and I bike year round. I mostly drive mid drives during the 8 months when the winter here is not too bad. In the coldest months I usually switch to a hub-motored bike, since the chain and drive train age like milk then anyway, what ever I do :).

But it would be nice to have some chain guard anyway since it rains a lot here as well. Perhaps I could fit one of those flinger ones, on the outside. They are just fastened via the screw threads that goes into the cranck arm: https://www.accord.com.tw/DISC-COVER-pd49694355.html

Since the Gustavo does not have any screw holes to fit a chain guard I mean.

As a side question: can the offset ever get too big ? Or is that very unlikely?
 
I have investigated further and it seems the actual offset of the Gustavo 42t is 18mm. Since it is a copy of the Lekkie bling 42t, according to a member on another forum. Do you think this one might suit both of my bikes man? Especially the fatbike perhaps? Since I am going fishing with that one, and I eventually hope to go hunting with it as well. If it works well.
You are mixing up BBSHD and BBS02 rings. the Gustavo BBSHD ring is 18.8mm. The Lekkie 42T BBSHD is 18.3mm. But the Lekkie BBS02 42T is only 9mm. Remember what I said above on lesser BBS02 offset? You are looking at the wrong motor's chainrings.
But it would be nice to have some chain guard anyway since it rains a lot here as well. Perhaps I could fit one of those flinger ones, on the outside. They are just fastened via the screw threads that goes into the cranck arm: https://www.accord.com.tw/DISC-COVER-pd49694355.html
I have seen people 3d-print BBSxx chain guards. I even have one that I bought from someone who was selling them for the cost of materials on Facebook but its not something I have ever used.
Since the Gustavo does not have any screw holes to fit a chain guard I mean.
What people have done is print a guard that uses the same bolt holes and then just use longer bolts and maybe a layer of washers for a spacer.
As a side question: can the offset ever get too big ? Or is that very unlikely?
Not unlikely at all. I bought my Luna Eclipse in 2018 for my 2Fat build but the offset was so heavy it hit the chainstay. It wouldn't work on my Stormtrooper either, and it wasn't until I think I built the Envoy that I had a bike it could fit on.
 
I thought so... It didn't take too much to find two out of the three needed measurements to calc a Gustavo BBS02 42T chainring offset.

First of all, here's your blueprint for properly calculating chainring offset.


Next, here is a schematic of a Gustavo 42T BBS02 ring. NOTE: Gustavo sellers advertise a 14mm offset, and once you know how offset is calculated, you know the 14mm claim is bull$hit :

Sff274aa41068404988457b60e1e6404fd.png


So from the outside top to the bottom is 14.2mm which is where the 14mm claim comes from. But you are also supposed to subtract half the width of the wide tooth, which in this case is 1.9mm. So we are down to 12.3mm and we haven't even gotten to the part where we have to subtract the thickness of the center base. That measurement is not given, but I typically see about 6mm. So... 12.3mm minus 6mm gives you a for-reals 6.3mm offset for the Gustavo 42T BBS02 ring.

So maybe its a mm or two more offset than that. Or maybe not. 6-8mm of offset is what you should expect for a BBS02 ring in that size.
 
So maybe its a mm or two more offset than that. Or maybe not. 6-8mm of offset is what you should expect for a BBS02 ring in that size.
I think I will order one. And perhaps go with 44 or 46 on the other one. This could be a good fit perhaps?

But over all you prefer the Lekkie over the Gustavo, right? Bigger offset and better quality? Only thing is the Gustavo is a lot cheaper so if I picked the wrong ring it would be easier to order a new one and so on. Shipping to Europe for a lot of this Lekkie stuff is not worth it so I normally go via Ali.
 
You are mixing up BBSHD and BBS02 rings. the Gustavo BBSHD ring is 18.8mm. The Lekkie 42T BBSHD is 18.3mm. But the Lekkie BBS02 42T is only 9mm. Remember what I said above on lesser BBS02 offset? You are looking at the wrong motor's chainrings.
In the kits for bbshd they also offer a 42 tooth with a guard. Not sure if this is any good. But if I order a new bbshd in the future, when I have the money, this might be a good one right? Not sure what the offset is on their own ring that comes along with the motor.

So the Gustavo for bbs02 is only around 9mm at best. What is the lekkie for bbs02? I am sure you have mentioned it already but I mix it up in my head.
 
I think I will order one. And perhaps go with 44 or 46 on the other one. This could be a good fit perhaps?
See above. I don't recommend anything other than a 42 for a newbie. Especially one running in hills on a BBS02. If you change from that you need to have a clear understanding of why you are deviating and some experience under your belt on wear and tear.
But over all you prefer the Lekkie over the Gustavo, right?
Nope. I use anything I can get my hands on. The Gustavo I own just arrived and has not yet been used. But I do have several Lekkies and if you can stomach the price, you won't be disappointed. But same goes for the Luna Eclipse, and that Deruiz has been fine in terms of wear.
Bigger offset and better quality?
Offset varies by model even within the same manufacturer. You have to look at what they say and decide if that offset is good, bad or indifferent to your individual job. One advantage of going with a Gustavo is if it is a bad choice you are only out a small amount of money.
Only thing is the Gustavo is a lot cheaper so if I picked the wrong ring it would be easier to order a new one and so on.
Yes. Scuttlebutt I hear is the Gustavos last long enough to make them worth the money, but not as long as a Lekkie.\
 
So the Gustavo for bbs02 is only around 9mm at best. What is the lekkie for bbs02? I am sure you have mentioned it already but I mix it up in my head.
Lekkie is about the same. Go to the Lekkie web site they list the offset right there. I knew the 14mm thing was BS just by reading it because the lesser offset requirement of the BBS02 comes from the motor. No chainring can do better no matter who makes it.
 
See above. I don't recommend anything other than a 42 for a newbie. Especially one running in hills on a BBS02. If you change from that you need to have a clear understanding of why you are deviating and some experience under your belt on wear and tear.
Well I do have some experience with destroying bike parts :) I have opened these motors up before several times and changed stuff and so on. So for the cruiser bike I might take my chances and go with the 46 tooth. And the fatbike probably 42, since that one seems to be heavy as s**t going uphill.

But although I will go with the 46 tooth for the cruise bike I will also read your manual thoroughly on how to drive a mid drive carefully. Never do the highest gear going uphill and so on. It was a very helpful article. A lot of common sense basically but sometimes someone has to write that down for you to understand it better.
 
I'll throw my 2 cents in on this topic. Tire size is a factor as well when making gearing choices. Example - On my BBSO2 powered delta trike I have a 52 tooth front gear, but it runs 20" wheels. That large gear was necessary to be able to get a speed range that tops out at the legal limit here in Canada of 32 kph. Note I usually run the middle gear at the back since my average speed is closer to a 20kph limit which works better on the bike paths here and sometimes slower due to the foot and bike traffic.

My other delta also with 20" wheels has a 500 watt geared Bafang front hub motor. My power runs the left rear wheel. This trike had a 56 tooth front gear. Again normally pedal 18 to 20 kph. But I sometimes ride with a very strong pedaler who likes to go fast when we find long safe stretches of road or trail. So I have purchased a 75 tooth front gear. By using the largest gear at the back the ratio will be similar to the 56 and down hills or with the wind I can get a bit more speed. Note where I live it is flat with wind being the biggest factor.

I am always aware electric motors need to be kept spinning at higher rpm's and lugging them kills them. My BBSHD runs a 42 tooth and on the singletrack trails is always on the largest or 2nd largest gear at the back. Ridden with care to keep the revs up has meant it has been running well for 9 years now. FYI speed on the singletracks I ride is usually 6 to 10 kph due to the many turns and trees.
 
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