Pedal assist sensor in Bafang mid drive

[Valerio]

Hello everyone,
I have a silly question:

is the pedal assist sensor integrated inside bafang mid drives?

I’m considering getting a bafang after 3 years using a 1000 W rear hub and im a bit tired of pedaling so hard when the battery dies...
I have seen a few videos and they all seem to require installing the speed sensor on the spokes, but that would be different than the normal PAS experience I have now with the disc magnet I’m afraid.

please let me know.
Thank you
V

 

[tomjasz]

BBSxx series motors, mid drives, have a speed sensor mounted on the chainstay, reading magnet revolutions. A PAS device with magnets on the BB is essentially doing the same thing.

 

[TomW]

Depends on the bafang motor model, As Thomas mentioned the BBSxx motors have what he says, and this is what you need if you want to use any frame.

But the ultra and a few others have internal motor sensors torque, cadence etc, and only have 1 external measurement which is the speed sensor which is just a magnet on a spoke, but you need a specific frame for these models so it is a little less of a DIY option.

In my experience mid drives tend to have a more natural feeling if that is what you are worried about, and you also have the advantage of putting the power through the gears which gives you more usable power.
But this also has the downside of extra wear on chains, cassettes etc.

 

[Valerio]

Understood, Do you guys think it will also be "lighter" to pedal with the system off like a normal bike?
right now with the hub I feel its really hard and the motor seems to remain "engaged" somehow internally, perhaps its the normal resistance of the internal gear?

 

[TomW]

There is hardly any resitance in the drive with the ultra, except for the extra weight it pedals exactly like any bike.
I expect the BBxxx's are the same. the motor completely disconnect's it has a 2nd freewheel/ pawled clutch in the bottom bracket.

I do not have much experiance with hub motor's but I do believe that most of them are perminantly connected which is why some offer regen charging.

 

[Valerio]

Thank you all for your replies, I'll start my shopping research and I'll might bothering you again for some opinions!
V.

 

[J.R.]

Understood, Do you guys think it will also be "lighter" to pedal with the system off like a normal bike?
right now with the hub I feel its really hard and the motor seems to remain "engaged" somehow internally, perhaps its the normal resistance of the internal gear?

A geared hub is the lightest drive system, unless it's a huge powerful one. It has no drag or cogging while pedaling. A mid drive has almost no drag, some have a little. A BBS will be a little heavier than a 350 to 750 watt geared hub. You likely wouldn't notice. A direct drive hub is the heaviest and it does have cogging drag while pedaling. Sounds like you have a direct drive now. They are beasts. I started with one and its difficult to maintain 10-12 mph on flat ground. I had to do 5 miles once without assist... what a workout!

 

[fooferdoggie]

A geared hub is the lightest drive system, unless it's a huge powerful one. It has no drag or cogging while pedaling. A mid drive has almost no drag, some have a little. A BBS will be a little heavier than a 350 to 750 watt geared hub. You likely wouldn't notice. A direct drive hub is the heaviest and it does have cogging drag while pedaling. Sounds like you have a direct drive now. They are beasts. I started with one and its difficult to maintain 10-12 mph on flat ground. I had to do 5 miles once without assist... what a workout!

well if your taking a the Bafang a bosch or such is lighter as it is lighter in the motor and it only needs a 36v battery.

 

[tomjasz]

it only needs a 36v battery.

While I have older 36V BBS01A motors, they are rather wimpy and require being smart about shifting. Many do manage to overheat them when not shifting coming to a stop and throttling away. BBSHD and newer versions are greatly improved.

 

[Gene02638]

only needs a 36v battery.

I would consider needing a 36v battery to be a negative, not a plus. 52/48 has more capabilities as well as efficiency I believe.

 

[fooferdoggie]

I would consider needing a 36v battery to be a negative, not a plus. 52/48 has more capabilities as well as efficiency I believe.

no you need that bigger battery because the motor is a power hog it adds weight to the bike. my bosch powered bike is really efficient and you get a lot of range out of such a small battery. plus the bike is lighter and that's always a plus.

 

[Clueless]

Understood, Do you guys think it will also be "lighter" to pedal with the system off like a normal bike?
right now with the hub I feel its really hard and the motor seems to remain "engaged" somehow internally, perhaps its the normal resistance of the internal gear?

Hi
If your feeling like your motor is engaged while unpowered then it actually may be just that,my bike had a bad Bafang hub motor and I discovered it quite by accident. Its easy to test just get the wheel off the ground and give it a spin it should spin easily 10 to 20 full revolutions before gently stopping and should not make a noise. Now if you do the same spin in the opposite direction you will hear a low sound and only get about 3 rotations.This will confirm your motor is ok
My bad motor made the low noise while spinning in both directions and only rotated about 3 revolutions.My motor was replaced by the seller and my bike is much faster coasting and easier to pedal.
Cheers

 

[AHicks]

Understood, Do you guys think it will also be "lighter" to pedal with the system off like a normal bike?
right now with the hub I feel its really hard and the motor seems to remain "engaged" somehow internally, perhaps its the normal resistance of the internal gear?

It sounds like the internal clutch in your hub drive is pooched and not releasing. There should be no drag on any geared hub that I'm aware of.