TONGXIN Datasheet/Dimensions/technical drawings ...

[Scottyf]

Shame you couldn't do something like this...
Disk brake sprocket adaptor - YouTube

 

[kitchenman]

nice find! ..

 

[Deleted member 4366]

It's all getting a bit complicated. I've two suggestions:
1. Sell the motor on ebay and but a more suitable one. Everything that makes a Tongxin good as a hub motor is wasted when using it as a crank drive.
2 Take the cover plate off, pull out the core and drill fixing holes for the sprocket. If there's enough thickness, tap a thread in them otherwise countersink from the inside and fix the sprocket with countersunk screws before re-assembling the motor. Which side do you want the sprocket - cover-plate side or the wire side?

 

[kitchenman]

I dont want to do either of those things! .. I've just completed a year of cycling with the Tongxin and I've got all the stats for all my journeys! and its been brilliant... If I succeed in using it as a crank drive or a chain drive for my recumbent then I am interested to know how it will perform .. if I dont succeed or if it doesn't perform well then I'll be putting it back in a wheel - so definitely dont what to sell it! ...
Regarding opening it up ... well .. if I have to then I will .... but at the moment I'm exploring ways of attaching a sprocket without doing that ... hence the clamp experiments ... d8veh, are these, in your opinion, going to fly? .... (probably not the best expression to use as I can see my HAC flying all over the place! >..
I'd like to know what you think about the seat clamp idea? The aluminum collar on the wire side is about 2mm . So , something like this:


For crank drive I'll use wire side. For chain drive I'll use the other side and 2 sprockets.

I forgot about this! :
http://www.jensonusa.com/store/product/BR605Z00-Problem+Solvers+Adapter+-+Ctr+Lock+To+Is.aspx

 

[Deleted member 4366]

My Bafang is really good as a crank drive. It pulled me up our steep test hill without pedalling 44/14 was chainwheel/rear sprocket, so that's not a very low first gear. I think an ebike with a motor that powerful on the crank would satisfy everyone and is to me how the power/torque should be. I would say loads more pulling power than a Panasonic and a bit more torque, though less power than a Bosch. It's better because it doesn't use a stupid torque sensor that makes pedalling hard work. I haven't done any top speed runs because the motor jumps the sprocket in top gear, but I guess the spped just depends on the gearing, wind and hills. It would pull downhill at any speed, which would give a lot more speed than a hub motor.

Opening up your motor is not a big job. It took me about 5mins to open my Cute, which is more or less the same.

I think your clamp arrangement might work as far as being able to test the potential, but I would prefer something more compact and robust as a permanent solution. I was surprised at how much force my motor made at a small radius. A rough calculation says about 30kg on the chain, so your clamping system needs to be pretty tight to resist that.

 

[kitchenman]

Thanks .. Thats encouraging ... and I am having fun thinking about the various clamping configuration.. What do you think about using something like the CTR Lock To Is Adapter? .. Obvioulsy there is no cassette to connect to and I'm not sure of the diameter but what if notches were cut into the 2mm aluminuim collar to provide some binding for it or a similar device? .. Then you would have clamping and fixing? ...

just looked at a cassette that I have on a hub on my desk and the diameter is the same as the seat post clamp. So... the CTR Lock To Is Adapter should fit nicely as well .... Looking at the ridge pattern on the cassette the ridges are about 1 mm so it seems feasible (to me) to emulate this by cutting the same ridges in the 2mm collar on the wire side of the Tongxin ...

 

[Deleted member 4366]

I don't think it'll be enough to resist the motor torque, and if it slips, It'll make a mess of your motor. Looks like you're going to have to drill through that motor casing sooner or later. That clamp'll make a nice drill-jig for the hole positions.

 

[indalo]

It's better because it doesn't use a stupid torque sensor that makes pedalling hard work.

And there was me thinking all along that a torque sensor was an intelligent piece of kit! I can't say pedalling is hard work with power switched on but it sure is when I meet a hill unpowered.

Indalo

 

[oigoi]

I dont want to do either of those things! .. I've just completed a year of cycling with the Tongxin and I've got all the stats for all my journeys! and its been brilliant... If I succeed in using it as a crank drive or a chain drive for my recumbent then I am interested to know how it will perform .. if I dont succeed or if it doesn't perform well then I'll be putting it back in a wheel - so definitely dont what to sell it! ...
Regarding opening it up ... well .. if I have to then I will .... but at the moment I'm exploring ways of attaching a sprocket without doing that ... hence the clamp experiments ... d8veh, are these, in your opinion, going to fly? .... (probably not the best expression to use as I can see my HAC flying all over the place! >..
I'd like to know what you think about the seat clamp idea? The aluminum collar on the wire side is about 2mm . So , something like this:
View attachment 2710

For crank drive I'll use wire side. For chain drive I'll use the other side and 2 sprockets.

I forgot about this! :
Problem Solvers Adapter - CTR Lock To Is at JensonUSA.com

Alan, in my opinion a clamp arrangement like the seat clamp on its own will not handle the torque and it will just spin and damage your motor. You need something to provide a positive lock for the sprocket, bolts, keys, dowels.something to stop the clamp turning. Not sure what thicknesses of metal you've got to work with, but if I were you I would be pulling the motor apart to get more ideas for what is possible.

For example you

 

[kitchenman]

I don't think it'll be enough to resist the motor torque, and if it slips, It'll make a mess of your motor. Looks like you're going to have to drill through that motor casing sooner or later. That clamp'll make a nice drill-jig for the hole positions.

I knew it would come in useful! ...

 

[kitchenman]

thanks oigoi. I haven;t totally given up on the idea of using the spoke holes. So a clamp with spider legs fixed to the spoke holes ...

 

[kitchenman]

Or.... a hub adapter collar (HAC) !!! - hopefully cut from a 103 mm diameter aluminium tube with a 7mm wall! .... and then tapped for spoke holes or new holes ....

Good day! ... here are some photos showing what I have been up to:

Crank - a set on Flickr

Sorted out battery location and solved some minor problems (quick release in the way, battery bottles hanging need strapping) ...
Fitted crank for stoke monkey solution .. (got it off a Raleigh that was at the tip - £8!)
Drilled holes in my new "forks"
Mocked up the HAC using some plumbing tubing and some food bag ties! ..

Tomorrow I'll get the motor in place after I make some drop outs! ... and take some more photos... start planning the cable swap over and start doing it! ...

 

[oigoi]

Looks good so far Alan thanks for sharing the pics

 

[kitchenman]

Thanks ... I'll use the "stokemonkey" thread for further updates ...