Adding a second front chainring?

red

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New to ebikes. Been looking for a mid-drive kit. Recommendations are welcome, for conversion kits. I plan to convert a 26" trail bike, for the nice suspension, but I do not plan to go off-roading. So far, the Bafang BBSHD Mid Drive Ebike Kit looks okay, but all mid-drives that I see have only one front chainring. I live in mountain country, and even the somewhat flat roads in town are not really flat. Various sizes of Bafang chainrings are available, so it seems possible that a second chainring could be added with a front derailleur, but I may be missing something. The reviews on the LunaCycle parts pages mention this possibility, but not much is there about the results. I expect to be careful when shifting, with little or no motor power applied for that instant, just normal pedaling. I expect to tinker with the path of the chain, to align the gears and chain properly. Those considerations aside, is there more I should know? Does anybody have experience with this concept and execution? Any pitfalls to avoid? TIA.

 
You can do this with the Bafang BBS kits. You will need a chain ring adapter.

(Turn on the subtitles for English)


Chainring Adapters:

Bafang BBS01/02:

Bafang BBSHD:
 
Anton,

Thanks, I did believe there was a good answer available, and it looks like you have it.
Is anybody here doing this two-chainring mod for the Bafang? Any tips?
I would hope to add two "chainguard" plates to this rig, to prevent dropping the chain to the inside or outside of the chainrings.
This "extra" mod may need longer bolts for the chainrings, but that is not a problem.
Thanks again.
 
I was apprehensive about hills too, but now that my bike conversion is done hills are no problem. Get a powerful motor like a Bafang 750 or 1,000 watt model and you're good to go. I've got a seven speed hybrid bike and the 750-watt Bafang BBS02 with only one 42t chainring in the front (it never had more than one). It soars up hills in 3rd gear with no problem. I pedal up steep hills like I'm pedaling on level terrain. No worries.

You might want to consider a Lekkie chainring though. They position the chain a little better when using the lower gears.
 
Hill,

From somebody with that screen name, I guess I better listen up. Even if I decide otherwise later on, I can always add things if needed. Thanks.
 
Hill,

From somebody with that screen name, I guess I better listen up. Even if I decide otherwise later on, I can always add things if needed. Thanks.
Yeah, hills were my main motivation for going electric.

The thing with front chainrings is that they’re always a compromise. The smaller ones are better at hill climbing; the larger ones give you more top speed. I went with a 42t and it’s great for hills. It tops out around 20 mph on level ground, which is fast enough for me. If you decide you want more speed you can always add another chainring later or try a bigger one. It’s not a big job. A 44t or 46t might also work for you, but I haven’t tried them. Once you go electric though, gearing actually becomes much less critical.

I recommend getting brake sensors and a gear shift sensor. They stop the motor momentarily when you brake or shift. They don’t cost much in the grand scheme of things but they save a lot of wear and tear on the drivetrain. You won’t even notice them doing their thing, but they’re good to have.

Good luck and enjoy the bike.
 
HillAversion,

Thanks, I knew about brake sensors, but a shift sensor sounds good, too. Bit by bit, I'm getting some good help here. Thanks again.
 
I'm 6'1" 240, my BBSHD has just an 8 speed rear cassette..I have a 42t front and can climb ANYTHING ALL DAY. The only hills it can't climb are so steep the limitation is traction and keeping the front wheel down..zero to do with gearing. 2 Chain rings up front is a waste of your time and efforts. and will kill chains when switching back and forth.
 
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