Bafang BBS01/02 on a bike with hub gear and footbrakes?

[Watt]

Hey,

I want to build a Bafang BBS01/02 (is there another difference but 250W/750W here?) on a beautiful locally produced bike. It has different options of Shimano hub gears. I have read that pedal assist on crank drive is a bad idea with hub gear. Does anyone know if this is true? If so, is it easy to only use the throttle on the BBS0X and disable pedal assist?

And does the crank drive make the bike a "fixie" (meaning that the crank motor would make the pedal spin whenever it is in use)? Or can I still have the pedal still while rolling downhill/throtteling?

I could build both with footbrakes and handbrakes. Is there a reason that a footbrake would be a bad idea? Just thinking that it could be some complications with the brakes being implemented in the motor system that I can't figure out...


thanks!

 

[ErikDK]

The freewheel allowing the motor to keep on driving while the crank is not turning (no it's not a fixie) also makes the use of a coaster/foot brake impossible.

If you have no mechanical feeling and shift gears on a hub gear while the motor is pulling, you will destroy it in short order.

Having a motor to assist means you wont be shifting gears nearly as often as without a motor.

If you can get a hub gear with roller brake, you will save yourself a lot of work on brake maintenance.

 

[teslanv]

I want to build a Bafang BBS01/02 (is there another difference but 250W/750W here?)

I know the BBS0X series comes in at least three different versions - BBS01 36V 350W, BBS02 48V 500W & BBS02 48V 750W.

 

[turbo1889]

Back pedal brake and mid-drive do not mix well together, Almost an IMPOSSIBLE combination. If your going to do a mid-drive then go with hand brakes.

Almost ALL internal hub gear boxes do not shift well under load. You must release motor throttle and stop pedaling for a second while shifting and then gently pedal into the gear and ensure its "set" before applying motor power. At least that is the shifting procedure I would recommend.

As to how well an internal hub gear box will handle the extra motor loads. It all depends on how much motor power you intend to put through it and to a certain extent how strong you intend to pedal along with the motor when its is being used and what specific internal gear hub you use. I personally have destroyed some internal hub gear boxes under pedal power alone. Where as other hub gear boxes have been able to withstand all kinds of abuse. I hesitate to mention specific ones in each category since my results being somewhat dated (to say the least) may not reflect the current production offerings and are more limited then others results who you can get by searching this forum.

 

[tomjasz]

I'm doing the same thing. From the dozens of other threads I've read, others find they don't shift much. But rather usually set the gearing, on a three speed for example, in 3rd and leave it alone. Workable?

 

[teslanv]

I'm doing the same thing. From the dozens of other threads I've read, others find they don't shift much. But rather usually set the gearing, on a three speed for example, in 3rd and leave it alone. Workable?

If you are choosing a Mid Drive you will be doing MUCH shifting. That is both a benefit and drawback of the mid-drive system. - Benefit because you can use low gears to climb steel inclines and high gears for high speed on flats and downhill. Drawback, because if you have hilly terrain like I do, you are constantly shifting, and the motor takes its toll on the drivetrain because of this.

Also, with a mid-drive, you generally loose the second and third chainrings, since that space is taken up by the motor pulley/gear. - So most Mid-drives only have use of one chainring gear. - Not a hug deal, actually, since really all you are losing are the very lowest gears from a typical 21+ speed drivetrain, which are not needed when you have 750W between your legs.

In contrast, a Hub motor is a single speed set-up from Zero to 30 mph+. In these set-ups most users may or may not shift. Some will keep their gear in high, and just pedal along once they are up to full cruising speed.

 

[samsavvas]

I'm doing the same thing. From the dozens of other threads I've read, others find they don't shift much. But rather usually set the gearing, on a three speed for example, in 3rd and leave it alone. Workable?

If you have no big or really steep hills I think this is perfectly workable. I have the 250w BBS01 on a 20" Moulton TSR with an 8 speed rear cassette and 56/11T top gearing. I ride it to work and my 'hills' are just the sort of inclines you'd find in a seaside/harbour environment - a few roads over what's left of the coastal sandhills and a couple of bridges. My gears and drive get left in high (56/11T) and PAS mode most of the time with an occasional shift down a couple of gears to ease the load on the motor a bit. I could just as easily leave it in high and pedal a bit more! I can easily cruise on 28km/h and 34km/h is not hard with a little effort. Both are actually quite fast in a busy urban environment.

In really hilly terrain the story may well be different of course and the 750W version may also be a different kettle of fish. I reckon though that for most flat(tish) city dwellers outside San Fancisco or Sao Paulo (ie; big hills) 1-3 gears are all that's needed with the 250W BBS01.

So with a little care I think a 3 speed IGH will work fine. Just don't shift under load (pretend you're driving a '30s Morris with a 'crunch' gear box) and you may have to experiment with rear sprockets a bit. I'm about to build up an old 'F-frame' Moulton Mk1 with a BBS01. It'll have an old Sachs Torpedo 3 speed and probably a 60T chainwheel. No back-pedal ('coaster') brake though. As far as I can see that's not possible with the BBSxx because of it's double internal freewheels. I'm afraid that the OP will have to lose that idea. ErikDK's suggestion of hub brakes is probably the best way to go and very much in keeping with a 3-speed's simplicity and reliability. I too have found Shimano roller brakes to be pretty good but so are S/Archer if you can get them.

Savvas.

 

[jateureka]

If going with the IGH then you can fit a gear sensor to help smooth out the shifting on the BBS01 and BBS02, but they are not cheap.
http://www.gearsensor.com

 

[teslanv]

I think a 3-speed would work great on the BBS0X Kits. At higher PAS settings, I find myself shifting 2 or 3 gears at a shot. All you need is Low, Medium & "VERY HIGH"' GEAR.

 

[tomjasz]

If going with the IGH then you can fit a gear sensor to help smooth out the shifting on the BBS01 and BBS02, but they are not cheap.
http://www.gearsensor.com

You found a price?

 

[jateureka]

I emailed them and they gave me their OEM/dealer pricing details, and the sample pricing, but the exchange rate for Euro to Australian dollars is not good, $1.50 to 1 Euro, so I haven't persued it further. The IGH sensor with BBS01 connector was around 30 Euro plus tax plus freight for small/sample lots.
I am still evaluating my 350W BBS01 and as yet have not found the cost justified. But for someone in Europe with IGH, or for BBS02 that are stripping gears then it may be worth while.

 

[samsavvas]

I am still evaluating my 350W BBS01 and as yet have not found the cost justified. But for someone in Europe with IGH, or for BBS02 that are stripping gears then it may be worth while.

I bet you could cobble one of these up using the cheaply priced brake cable movement detectors sold by EM3ev, BMS and GBK. Same principle init?

Savvas.