Bafang BBS02 resistance

[tomjasz]

but not excessive, and as he describes,

Sadly there is no measurement to use. I've seen this a number of times. There is drag. The motor isn't designed for acoustic pedaling. It's an assistive device. The fella needs to sort his mileage and not get stuck pedaling. ALL motors have drag. Some less some more. My BBSHD was more difficult than my BBS02. The BBS02 has more drag than my BBS01. But none are enjoyable pedaling without power. My DD drives are horrible and my GD hubs are somewhat better but for my gimpy legs all are nearly impossible.

 

[AHicks]

I've never seen or ridden a bafang mid drive. If it is like the tongsheng with the one way bearings there shouldn't be any motor drag, should there? When pedaling with the motor off or faster than the motor is running assist the one way bearing in the nylon gear that runs the reduction gear disengages the motor, is that not correct? In that case the only added drag would be due to bearing and gear friction which is certainly more than a simple bottom bracket cartridge (as seen in the posted videos) but not excessive, and as he describes, unless there is some unusual bearing or gear problem that only manifests when pedaling under load. Added weight of the motor and battery definitely makes a difference to me but to OP discounts that.

100% correct, TS and Bafang set up the same. Agreed, the only resistance should be the drag created by the bearings.

 

[tomjasz]

100% correct, TS and Bafang set up the same. Agreed, the only resistance should be the drag created by the bearings.

There are internal components turning. Look at the design again. It's not just an axle and bearings. How does your ultra pedal without power?

 

[AHicks]

There are internal components turning. Look at the design again. It's not just an axle and bearings. How does your ultra pedal without power?

Expand a little please. If the motor clutch is released, what is turning internally?
Forgot, the Ultra rides like a big heavy bike riding on 2.8" wide tires when the power is shut down.

There are no expectations of it acting like a light weight analog with tire inflated to 90psi. -Al

 

[EMGX]

For the tongsheng the only things turning and subject to friction and inertia to overcome (when assist is off or when pedaling beyond the assist support) are the axle/axle bearings (no different than a standard bottom bracket cartridge), the large and heavy main gear the small reduction gear and the one way bearing in the nylon gear that runs off of the motor shaft,. None of that is noticeable as increased effort to me when riding, the overall weight is definitely noticeable though. I don't see how the Bafang mid drive would be any different as it has essentially the same component array, at least as I understand it.

 

[tomjasz]

at least as I understand it.

So if you pedal power off you have zero resistance? Not theoretical, what do you experience? I donated my TSDZ2 bike build but I'm certain I experienced resistance with power off.

 

[tomjasz]

the Ultra rides like a big heavy bike riding on 2.8" wide tires when the power is shut down

Like EVERY Bafang mid.Regardless of tire size. RESISTANCE. There's no escape!

 

[EMGX]

So if you pedal power off you have zero resistance? Not theoretical, what do you experience? I donated my TSDZ2 bike build but I'm certain I experienced resistance with power off.

No such thing as zero resistance. Even a standard bottom bracket cartridge has resistance, it is just very low. With assist off I feel no additional resistance riding the tongsheng. If you spin the cranks on a stand there is a definite difference, a good twirl spins many times in either rotational direction with a standard cartridge and chain removed, the TSDZ2 will spin a slightly less when spun in reverse where the sprag clutch is disengaged, spun forward it doesn't spin as well - then it has to overcome stationary inertia of the large main gear (which weighs about a pound and a half in and of itself) as well as friction with the meshing and turning of the gear - less so with the small reduction gear and the one way bearing (disengaged). I don't see why a Bafang would be any different unless the main gear is heavier and/or the bearings are tighter. The motor shouldn't be turning at all pedaling with assist off. The luna video I posted shows how hard it would be if the one way bearing is jammed, then you are trying to turn the motor over at a whatever rpm the reduction ratio dictates.

 

[tomjasz]

No such thing as zero resistance. Even a standard bottom bracket cartridge has resistance, it is just very low. With assist off I feel no additional resistance riding the tongsheng. If you spin the cranks on a stand there is a definite difference, a good twirl spins many times in either rotational direction with a standard cartridge and chain removed, the TSDZ2 will spin a slightly less when spun in reverse where the sprag clutch is disengaged, spun forward it doesn't spin as well - then it has to overcome stationary inertia of the large main gear (which weighs about a pound and a half in and of itself) as well as friction with the meshing and turning of the gear - less so with the small reduction gear and the one way bearing (disengaged). I don't see why a Bafang would be any different unless the main gear is heavier and/or the bearings are tighter. The motor shouldn't be turning at all pedaling with assist off. The luna video I posted shows how hard it would be if the one way bearing is jammed, then you are trying to turn the motor over at a whatever rpm the reduction ratio dictates.

it's a matter of perception IMO. i thought my TSDZ2 was just as resistant with power out as my 2014 bbs01 motors. my bbshd motors were far less than my DD motors, but NO motor was designed for the low resistance of an acoustic bike. These are assistive devices designed to power with batteries. NOT pedal bikes! It's a ridiculous argument and complaint.

 

[Tom@WashDC]

No such thing as zero resistance. Even a standard bottom bracket cartridge has resistance, it is just very low. With assist off I feel no additional resistance riding the tongsheng. If you spin the cranks on a stand there is a definite difference, a good twirl spins many times in either rotational direction with a standard cartridge and chain removed, the TSDZ2 will spin a slightly less when spun in reverse where the sprag clutch is disengaged, spun forward it doesn't spin as well - then it has to overcome stationary inertia of the large main gear (which weighs about a pound and a half in and of itself) as well as friction with the meshing and turning of the gear - less so with the small reduction gear and the one way bearing (disengaged). I don't see why a Bafang would be any different unless the main gear is heavier and/or the bearings are tighter. The motor shouldn't be turning at all pedaling with assist off. The luna video I posted shows how hard it would be if the one way bearing is jammed, then you are trying to turn the motor over at a whatever rpm the reduction ratio dictates.

Definitely pedal resistance on the Ultra Motor w/o power. Enough to make it unenjoyable.

 

[EMGX]

I ride without assist regularly and use assist liberally but as little as I'm able when I want it. I'd be interested in trying a Bafang for comparison but probably never will. I can say that my Yamaha PW-SE bike performs very similarly to the tongsheng. As I said, the big issue for me is weight. I've installed and then removed the tongsheng from 6 of my bikes. Bikes without the extra weight are much more pleasant to ride - until I want or need assist. With neither the Yamaha nor tongsheng does any extra effort pedaling without assist seem significant or even noticeable (although if ridden back to back with and without motors it might be more noticeable).

 

[EMGX]

Definitely pedal resistance on the Ultra Motor w/o power. Enough to make it unenjoyable.

Then I guess that I'm not interested in trying a bafang mid drive after all. Tongsheng offers a pretty high end riding experience at a relative bargain price (compared to Yamaha, at least).

 

[tomjasz]

Then I guess that I'm not interested in trying a bafang mid drive after all. Tongsheng offers a pretty high end riding experience at a relative bargain price (compared to Yamaha, at least).

To bad. It’s different but a good motor. That said I’ve completely done a 360 and gor many the TSDZ2 may be a better choice. But both are resistant in power out.

I may have just talked myself into a new TSDZ2 for my second trike.

It’s all good if you have realistic expectations,

Ride it like you stole it,
Tomjasz!

 

[rccarguy]

Thankfully I got a refund with the kit. I'd be pretty annoyed paying for product like that.
The resistance feels like riding a MTB through 1" soft mud that the tyre is sinking into.

On a flat road, keeping to the same mph requires a lot of effort. I've carried 30kg in a rucksack and it's worse than that (to keep speed up it really doesn't make much difference, as power resistance is low on regular bike)

Hard to quantify, as it's only under load, not in the work stand. As I said you can use your pinky and spin the cranks. It does feel slightly more than a regular decent BB but not a lot.

If I need to buy a new motor it would be from a UK supplier, go into the shop, let them ride my bike requiring their motors aren't like that.