80mm Tongxin question

[Pedalo]

When the slippage occurs, does it cause any damage to the motor?

 

[AndyOfTheSouth]

Flecc - good point about how Cytronex might avoid the slippage problem, but we still don't know if they are using what now seem to be the earlier, more powerful versions.

 

[flecc]

When the slippage occurs, does it cause any damage to the motor?

It hasn't appeared to normally, the slippage usually only being momentary. In the earlier days there was a problem at times with their two piece spindle which might have been related to more sustained slippage, since this was mainly in the USA where the applications were usually with large wheeled bikes using lower revs motor versions. We don't seem to be suffering in this way in Europe.
.

 

[HarryB]

Very interesting thread, this. I wonder if Didi has any comments from a German perspective or his own experience of the Tongxin clone?

Harry - isn't the onus on Cytronex to sort out your bike? That power reduction must be maddening!

More generally, if Tongxin has reduced the power of the motors intended for 26" and 700c wheels, wouldn't this have implications for Cytronex? Unless they use different versions and perhaps deal with slippage problems differently eg via customised controllers.

I do find it annoying that I have ended up with a bike differently to the one I originally test rode. The annoyance factor is that it was pretty much perfect before and I was so happy riding it. However I don't think it is in any way the fault of Cytronex. Mark has been very upfront about it and these are the motors that Tongxin are supplying and there is nothing he can do about it. I could buy a 190rpm motor but that may end up being too fast and reduce the range - £235 is a lot of money to spend on an experiment. I have other plans for the money, a little nice ebike project.

The latest generation of Cytronex have pedelec sensors so you will naturally pedal before the power kicks in so avoiding slippage. The latest motors don't really slip anyway so I cannot see there being a problem. Cytronex use standard controllers not customised ones by the way.

Yes I too would be interested in the Mini-FWF. I would prefer the power and find other method of avoiding the drive slippage.

 

[didi28]

Very interesting thread, this. I wonder if Didi has any comments from a German perspective or his own experience of the Tongxin clone?

I don `t know, whether I have a "German" perspective, but I have one of my own !

The Tongxin/FWF is in some way constructed for a controlled slipping above a defined torque. The steal sun-wheel is a little bit elliptic and sun-wheel and the planet-wheels are embedded in grease and pressed together by the hollow wheel.

So you have two ways of power transmission:
If you start with full speed without pedaling or other brutal force treatments the elliptic sun-wheel transmits most of the motor-power only when the longer part of the elliptic sun-wheel passes one of the planet-wheels, the rest it will slip.
After you have gained speed or treat the system normally, the sun-wheel transmits power with the narrow part of the elliptic sun-wheel also.

The big advantage of this propulsion is, that this (small and almost noiseless) motor can easily reach a good rotation speed, which should be about 80 % of the rated rotation speed, what is quiete efficient. But you shouldn `t stay too long in the slipping part of the transmission. The motor will get too hot, the grease will burn etc. That`s why this nice little motor is nothing for non-comform (too much volt or ampere) use.

I drive the 36V-motor now more than 1000km with the programmable 3-speed-switch controller from Das Elektrorad von Frank Scheftlein: Komplette Pedelec- / Elektrofahrrad Umbausätze und Ersatzteile von Bafang, Puma (eZee), Tongxin u.a..

The 3-speed-controller is functioning in PAS-mode in a "creeping in" manner of motor-support, when not using the throttle. This fits perfectly to Tongxin/FWF. 10 Amax is programmed and I use a 36V battery für the 36V-motor. It is even build in a 28" wheel and it works fine. But I want to ride bicycle with some motor-support and not ride a moped with the opportunity of cycling .

And the best: Really no one sees or hears, that I use a motor .

 

[HarryB]

can you remind me which motor you fitted to your 28 inch wheel, 190rpm or thereabouts?

 

[didi28]

I didn`ask for special data from Frank, but the motor is originally for a 26" wheel. In 28", full 36V battery (42V) and no-load the motor is running ca. 32km/h. You feel good motor-support `til ca. 28km/h. In Germany this is very likely within the legal tolerance, which is important for me.

 

[HarryB]

sounds like 190rpm then.

 

[AndyOfTheSouth]

Lots of interesting and useful stuff - thanks, folks.

One question which has been lost is Erik's on what freedomebikes experience has been with the performance on 20" wheels.

A supplementary on that is whether the Dahon 80mm fork can be safely bent (and bent back) to accommodate a 100mm motor.

 

[jerrysimon]

A supplementary on that is whether the Dahon 80mm fork can be safely bent (and bent back) to accommodate a 100mm motor.

Surely the answer is to use a 80mm Tongxin ?

Regards

Jerry

 

[AndyOfTheSouth]

Fair point, Jerry. It's because I'll probably use a 100mm motor (Tongxin or the new Bafang) in a 26" wheeled bike first. If its performance in that is unsatisfactory, I would like to move it to a 20" wheeler and wondered if that were feasible.

Oh5rm - thanks for the comments on the Dahon. I tried a couple a day or so ago and was impressed. The problem about electric motors is that they are all more or less OK on the flat, but what really sorts them out is the hills. I wouldn't expect a Tongxin or clone to give much support - if any - on a very steep (12% or more) hill in a 26" wheel. Andrew of Freedomebikes has written convincingly of their success in Bromptons with their 16" wheels. Erick had asked if he had equivalent experience with them in 20" wheels.

 

[didi28]

I wouldn't expect a Tongxin or clone to give much support - if any - on a very steep (12% or more) hill in a 26" wheel.

The support is no soo bad, but if you live in a mountainous region it is not the appropriate motor. Sooner or later it would kill the motor. Bafang is better for such things, but in a realistic point of view hub-motors in 26" or 28" wheels are nothing for long and steep hills. A chain-motor is much better for this purpose.

 

[apshamlton]

Freedom Ebikes uses both the 80mm and 100mm version of the Tonxgin motor.
In our testing the 80mm motor is slightly less powerful in the 0-5kmph rpm range (at startoff) but is the same for the 5-25kmph rpm range.

We have found it reliable with only very occasional ring failures.
Each motor has its ring individually checked out of the factory these days.

We should soon have the capability to replace any broken rings and thus repair the motor.
Parts pricing is now available on the website Freedom E-Bikes - Home