Bafang BB xx dual chainring mod

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opperpanter   100 W

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Re: Bafang BB xx dual chainring mod

Post by opperpanter » Feb 06 2015 2:57pm

Here's a video of a French guy with a dual chain ring mod.
Not sure where to by this adapter.
He also uses only 6 gears on the rear to keep a better chain line.
http://youtu.be/bpBxfhn0Px0

leo99   100 W

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Re: Bafang BB xx dual chainring mod

Post by leo99 » Feb 07 2015 8:29am

here is the link to the page for the adapter
iz would seem that you have to manualy change the front chainring and you can only reach the 3 last rear chainring when on the big front chainring

http://www.ozo-vehiculeselectriques.com ... r-pedalier
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Warren   100 kW

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Re: Bafang BB xx dual chainring mod

Post by Warren » Feb 07 2015 11:55am

If you use the front derailleur adapter for fat bikes, you can shift dual chainrings. The chainline will not be an issue for bikes with a long chain run...cargo bikes, and recumbents.

sanzo   100 µW

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Re: Bafang BB xx dual chainring mod

Post by sanzo » Feb 08 2015 7:45pm


egosphere   1 mW

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Re: Bafang BB xx dual chainring mod

Post by egosphere » Jun 10 2015 1:18pm

Any one ever try one of these: http://www.edibike.it/prodotto/corona-d ... trale-bbs/
It's a double chain ring machined especially for Bafang BB0x. I suppose it's made to wrap around the motor like the stock rings to get the right offset -- which you wouldn't get from attaching multiple chainrings on a spider. A bit pricy though.

opperpanter   100 W

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Re: Bafang BB xx dual chainring mod

Post by opperpanter » Jun 13 2015 2:02pm

egosphere wrote:Any one ever try one of these: http://www.edibike.it/prodotto/corona-d ... trale-bbs/
It's a double chain ring machined especially for Bafang BB0x. I suppose it's made to wrap around the motor like the stock rings to get the right offset -- which you wouldn't get from attaching multiple chainrings on a spider. A bit pricy though.
It looks like this:

Image

And I am curious too!

Would have been better to have a 38/48T, but that would move out both rings out a lot.
In the picture it looks like the 42T wraps around the motor, so it's moved inwards quite a bit compared to the stock chain ring.

tinasdude   100 W

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Re: Bafang BB xx dual chainring mod

Post by tinasdude » Jul 11 2015 3:16pm

The inner ring appears to be dished like the Lekkie

tinasdude   100 W

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Re: Bafang BB xx dual chainring mod

Post by tinasdude » Jul 17 2015 7:25am

Alcedo Italia makes a 38T that does no require an adapter. Piggy back it on their offset 41T

NFN01   1 mW

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Re: Bafang BB xx dual chainring mod

Post by NFN01 » Jul 28 2015 3:49pm

Samd wrote:I had a customer send me some info recently of a dual chainring on his BBS powered recumbent.

He used one of my 104BCD chainring adapters and a dual chainring in conjunction with a fatbike (100mm) derailleur setup to shift it all outboard a bit. Seemed pretty happy and sent me a rundown as he felt it was a useful option for the adapters.

He now runs both 48T and 32T on his BBS setup. Torque and speed options.
20141014_154516.jpg
Yep, that's my KMX trike.

Just to confirm Samd supplied the adapter. My mate bought a spider that came with a 3.2mm spacer disc from some in Australia. I bought the spacer from him and that allowed the double setup you see.
The dual setup has been running without a hitch as gives the BBS02 a new lease of life when hill climbing the really steep ones. The front 48T/38T now drives a nuVinci N360 CVP controlled by their Harmony Intelligent Electronic Shift System. The road speed at a cadence of 100rpm is 37.5mph on the 48T to 18T hub sprocket with the hub on full over-drive.
I very rarely use the 38T, only for uphill gradients greater than 15%. The system runs really well on the 48T for pretty much most riding and terrain conditions. I am consider upsizing both chain rings by 2 maybe 4 teeth (I cannot exceed a 10T difference between the two chain rings due to limitations in the chain tensioning system).

It will only work well on bikes where the distance between the crank and rear axle is 1 metre or greater. I.E. Longtails, cargo bikes, recumbent bikes/trikes.
It WILL NOT WORK on standard diamond frame style bikes due to the large amount of chain deflection outside of the normal chain line outer limit, for it to reach over to the chain rings.
I know. My mate who supplied me the spacer tried it as an experiment on his MTB. He couldn't fit a front derailleur because he did not have a fat bike adapter. He manually placed the chain on each chain ring in turn and did some test rides with it. He found that from the third largest to the largest rear sprocket when using the small front chain ring the, chain kept jumping off the sprockets. On the large chain ring he could only use the three smallest sprockets else the chain kept jumping off. His plan to double stopped there, hence my ownership of the spacer.

The double setup on the BBS01/02 will work well for those who have the right type bike to install it on.

N

pn_day   1 µW

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Re: Bafang BB xx dual chainring mod

Post by pn_day » Aug 08 2015 5:12am

Very interesting discussion - and great to hear of a working solution for recumbents.

NFN01   1 mW

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Re: Bafang BB xx dual chainring mod

Post by NFN01 » Jun 22 2017 12:19pm

Samd wrote:I had a customer send me some info recently of a dual chainring on his BBS powered recumbent.

He used one of my 104BCD chainring adapters and a dual chainring in conjunction with a fatbike (100mm) derailleur setup to shift it all outboard a bit. Seemed pretty happy and sent me a rundown as he felt it was a useful option for the adapters.

He now runs both 48T and 32T on his BBS setup. Torque and speed options.
The attachment 20141014_154516.jpg is no longer available
Well. Over 3800 miles done on the old setup. Chain rings and rear sprocket 'shark toothed' and chain about half an inch longer than it was, when I bought the trike.
So an entire change of drive train parts and an upgrade on the chain rings to 42T and 58T and a 5 arm 130 BCD adapter. Rear transmission was also upgraded to an electronically controlled nuVinci N360 CVP hub. Which is still working perfectly after the all mileage it now has on it.
20170620_190319small.jpg
20170620_190319small.jpg (62.1 KiB) Viewed 1785 times

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