Suzhou Bafang Motor compare to Tongxin Motor

[flecc]

I side with fishingpaul on this Mr Ching, and I think you miss the point of why so many of us like the Panasonic system.

Time after time, people have posted in here that they enjoy cycling and just want a bit of help on hills etc, but not high power and weight. They want a bike that still rides like the ordinary bike they've always enjoyed.

As good as your bikes are, they just don't do that. Like all hub motor bikes, they either operate like motor vehicles on a throttle, while accompanied by pedalling, or they operate on a pedelec system that is vastly inferior to the Panasonic one, supplying power in a fashion that isn't well related to the cycling effort.

Each type of bike has it's own value for different likes and uses, but you make a big mistake in repeatedly inferring that those of us who like the Panasonic system must be stupid or ignorant.

We're not. We are well aware of the system's power input, we've ridden them for years after all, more than you've done. We just enjoy true cycling like all cycling enthusiasts, and like the way in which the Panasonic system doubles the power of each pedal stroke while remaining true to pure cycling, not in any way a motor vehicle.

On the newest units, the fact that there is now a switchable higher power mode which, despite your protestations, gives a very real boost to the power provided on each pedal stroke, is now an added benefit while still retaining the same cycling quality.

In addition, as you've conceded in part, there's the little matter of quality and reliability, the Panasonic powered bikes being the most dependable and reliable of any e-bikes in any road and weather conditions.

And as if all this is not enough, the central power unit and battery makes the bike far better balanced and gives the considerable benefit of normal cycle wheels with correspondingly easy puncture repairs and tube and tyre replacements.

Of course the extra range comes from our cycling input, that's the whole point, a bicycle that's efficient enough to use our cycling input more effectively than hub motor bikes do. It's got nothing to do with us imagining power, and for you to say so is insulting.

Instead of this recent regular attack on the competition which does you no credit, surely it would be better if you concentrated on further improvements in your own bikes to match at least some of the qualities I speak of? We would all really welcome that.
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[frank9755]

I'll also side with Fishingpaul and Flecc.

I think the Ezee range has a lot of strengths but the key area where it appears not to score as highly is quality of the cycling experience and ability to enhance rather than replace the power of the rider. The Ezee bikes seem to me to be aiming for the light moped / cruiser model, with a powerful motor but reduced cycling qualities. The changes to the new Torq strengthened my view of this. While there's nothing wrong with that; there is clearly a market for a quality high-powered cruiser style bike. However, there are other segments of the market containing customers who are looking for much more of the 'enhanced cycling' model.

The Panasonic motor clearly delivers that, hence its success.

My short ride yesterday on my Tongxing powered bike showed me that it gives an experience of that sort too. We were all very sceptical of the AtoB review of the Brompton Nano, which uses the Tongxin motor, many of us pointing out that the rider was spending most of the time cycling above the cut-out speed of the motor. Riding the Tongxin yesterday, I was able to do the same, and it brought it home to me that that is just the point, as on brushless hub motor powered bikes, you simply can't cycle with pedal power above the cut-off speed. The motor resistance is too high. This is the case on my Powacycle and Wisper, and i've read others say the same of Ezee bikes such as the Torq. You could do this on my old Powabyke, which has a brushed motor - and that made it a better cycling experience. I'm sure you can on other brushed motors such as Heinzmann, and probably the Ezee Liv - which its owners seem to rave about.

So, Mr Ching, I think what you say is valid but only for part of the market. There is a significant segment that actually wants what the Panasonic and Tongxin deliver better than a higher powered brushless hub motor in a cruiser style bike can. Maybe we just need to buy other products, but if I were you and were looking to add to my existing range, this would be the obvious gap I would look to fill!

 

[flecc]

So, Mr Ching, I think what you say is valid but only for part of the market. There is a significant segment that actually wants what the Panasonic and Tongxin deliver better than a higher powered brushless hub motor in a cruiser style bike can. - - - - - - - - - - - - but if I were you and were looking to add to my existing range, this would be the obvious gap I would look to fill!

And that of course is exactly what 50cycles did, fill the gap Frank speaks of with the Kalkhoff-Panasonic brand, complementing the eZee brand to provide a more complete range of electric bike types to suit both types of customer.
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[Jeremy]

What's really needed is intelligent pedelec control, I think, much as was discussed on another thread here. I'm trying to find a way to do this at the moment. What I hope to achieve is an add-on control system that can make any suitable motor behave in a fairly similarly to the way I believe the Panasonic system does.

The key seems to be getting a simple way to measure pedal torque and timing, without using one of the "sprung bottom bracket" pedelec systems. Non-contact chain tension sensing seems a reasonably good way to do this.

If a controller kit was available that did what I'm trying to do I'm sure it would be popular, as I doubt many of us really want the hassle of a throttle control.

Jeremy

 

[flecc]

I agree Jeremy, such a control could greatly improve some hub motors, though many might need redesign of their planetary gears to withstand the power pulsing stresses. The helical gears in the Panasonic unit are beautifully made motor cycle like precision parts probably for just this reason:

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[Leonardo]

I too think that what Mr. Ching says about the Panasonic powered bicycles and the Nano-Brompton doesn’t help correct information. The experiences we have on the Italian forum with the Biketech Flyer completely confirm what Flecc and the others say about the Kalkhoff, and our first experiences with a Nano-Brompton give even better results than the A to B test.

By the way, we have some video of the fitting of the Nano-Brompton and of some tests of it, also running uphill >20-25%. Files are quite big and slow to download (and in Italian), but for someone really interested they are the only ones of this kind, as far as I know. And here is an additional report of a journey on the Alps, more than 1000m gradient.

 

[frank9755]

I've just noticed the label on my Wisper 905se motor and it is a Suzhou Bafang.

Frank

 

[Grizzly Bear]

Hi guys
am I right to assume that seeing that my Tongxin is now approaching 2000 miles, that it is about to give up the ghost on me any day now? How am I to tell when this is about to happen? as it's going just as good now as when I first used it. I think you are bias towards a bike that is not legal in this country even restricted, do so at your own peril!
One point that you may think about:- If it wasn't for speeding motorists, we would not have speed cameras, sleeping policemen etc. We are in control of our own destiny. Yes the Tongxin does not have the performance of the Torq, but at least it's legal, think about it! Stay within the law.

Griz

 

[flecc]

I'm not biassed against it Griz, but I've just taken note of the reports of failure of the roller drive system, plus some minor part failures elsewhere.

If the roller drive system can be made to be reliable in all examples and applications, I'm strongly in favour of it's advantages of low friction losses and silence.

It doesn't seem to be there yet though, especially in applications that give the greatest starting resistance.
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[Grizzly Bear]

Hi Flecc
Well I'm still waiting for it to happen, I can't wait to have a look inside my one because I can't see as it has the type of drive you say, I am an engineer by profession and I can't see how it would work, as I say "I can't wait for a look inside" but not until it breaks. The rollers I guess are part of the free wheel, simular to a motorcycle starter clutch.

Regards Peter

 

[flecc]

I believe it's just like a normal hub motor Peter, except rollers in place of gears. An orbital smooth track in the hub casing, a centre drum, and a set of caged rollers between them, all under pressure to maintain traction, so presumably a taper involved. The potential is there, locomotives pull 500 tons or so that way, with just steel on steel friction, so if the engagement pressure can match the load over time, it could be ok. It's that last bit that concerns me, over time.

I've got the same question mark over the NuVinci hub gear, also using steel on steel small area friction drive, with some very questionable fluid compression involved as well.
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[Grizzly Bear]

Well how does it free wheel? This will only be resolved when I strip my motor I think, and I will, not tonight of course as I have have to get to work in the morning no that should be a

The forces required to do as you say would be quite considerable, and will have considerable resistance, this is not evident on my example anyway.

 

[flecc]

On a normal hub motor the freewheel is in the motor to orbital gear drive, so the orbital gears are always engaged with the hub, only the motor freewheeled. I assume the Tongxin is the same. There shouldn't be too much resistance if the track accuracy is high, as bearings aren't involved, just surface rolling.

I drew a representation and explanation of this on my Torq site here.
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[Sagittarius]

Hello,

Just for information, Rabeneick / Epple / Kreidler and probably Alu Rex bikes commercialized in Germany by Cycle Union GmbH are equipped with Suzhou Bafang hub motors.
I bought last december a Rabeneick model Vitality Pro. There is also some other 2008 models from this german brand (same with Kreidler).
I have to say that for the moment, I'm quite convinced.

 

[Leonardo]

The Alu-Rex 36V, the Kreidler and Rabeneick e-bike and the 26" Epple e-bike are special versions of the "Dinghi" made by the Italian "Tecnocarbur": do you think they are using the Suzhou motor as well?

 

[flecc]

Enlargement shows the casing is the same in every detail Leonardo, but the surface finish appears to be lower grade if the photo hasn't been changed in some way that alters it. Therefore it may not be an identical model.
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[Sagittarius]

The Alu-Rex 36V, the Kreidler and Rabeneick e-bike and the 26" Epple e-bike are special versions of the "Dinghi" made by the Italian "Tecnocarbur": do you think they are using the Suzhou motor as well?

I've tried to find a Dinghi model but the website seems to be out of order.
Getting some images on google, it seems theses models have a rear motor not a front one ?

I think the 28" Rabeneick Vitality Pro / Kreidler Limoges are quite different (Phylion Lithium 10 Ah 36 V 400 cycles battery, Alu 7005 frame, SRAM Spectro 7 ...).

Here is mine ;-) Leonardo:

 

[Letmann]

how is "steel friction" working

"The Tongxin motor doesn't use planetary gears, instead it has a planetary roller drive relying on steel on steel friction to avoid slipping."

Hi,

Can somebody explain how "steel friction" is working.
wenn gears are used i can understand it,
but wenn there are no "teeth" how can they stop slip.


Letmann

 

[flecc]

"The Tongxin motor doesn't use planetary gears, instead it has a planetary roller drive relying on steel on steel friction to avoid slipping."

Hi,

Can somebody explain how "steel friction" is working.
wenn gears are used i can understand it,
but wenn there are no "teeth" how can they stop slip.


Letmann

I haven't the exact details of the internal construction, but it's pressure on the rollers that maintains the drive. In fact on high torque applications such as when high geared in a large wheel, the drive does momentarily slip if powered from a standstill.

The NuVinci continuously variable hub gear uses steel balls to transmit the drive via point contact and that works ok, again there's pressure involved to maintain contact.

The principle of using pressure is the same as the case of a railway locomotive where weight provides the pressure to enable drive on smooth rails.
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[rog_london]

Well how does it free wheel? This will only be resolved when I strip my motor I think, and I will, not tonight of course as I have have to get to work in the morning no that should be a

The forces required to do as you say would be quite considerable, and will have considerable resistance, this is not evident on my example anyway.

There are some splendid free-wheel arrangements which look just like roller bearings - I first came across those many years ago. When you look at the thing carefully some of the rollers are not quite round - they have slight corners to them - and there can be more than one shape used. They're assembled in a particular order, and what happens is that when the thrust is in one direction it acts just like a roller bearing should, except the 'odd' rollers slide but don't revolve relative to the races. Apply thrust the other way though and the thing jams and locks up solid. A beautiful piece of lateral thinking on the part of a clever mechanical engineer.

They're sometimes referred to as roller clutches. They're totally silent and mechanically very robust indeed.

Honda use a variation on that for the free wheel used on some of their starter motors on motorbikes. Those cope with a serious load, and probably you wouldn't get away with a tooth and pawl free wheel (apart from the noise!)

Rog.