80mm Tongxin question

[AndyOfTheSouth]

Hi folks

Does anyone know anything about the 80mm Tongxin? Does it have the same torque and level of reliability as the 100mm version?

Thanks

Andy

 

[jerrysimon]

Andy I almost purchased one from Frank in Germany. I really want the 100mm one though. If you mail Frank he replies really quickly and can probably comfirm for you.

Google Translate

He doesn't have any 100mm ones, so I have emailed the manufacture in hope they might sell me a 100mm one but no luck yet after a day or so

Regards

Jerry

 

[AndyOfTheSouth]

Thanks, Jerry - I've been in touch with him. I'd wondered if anyone had had any experience of the 80mm version.

 

[flecc]

http://translate.google.com/translate?hl=en&sl=de&tl=en&u=http%3A%2F%2Fdas-elektrorad.de%2Ftechnik.htm

I have emailed the manufacture in hope they might sell me a 100mm one but no luck yet after a day or so

Jerry

Tongxin briefly supplied direct some while ago but then stopped, saying that all personal sales must be through national agents. Their communications to individuals are often slow or absent.
.

 

[AndyOfTheSouth]

Another question. Can an 80mm motor be fitted without harm to a 100mm fork? Would it be a matter of using washers or bending the fork? If the fork is narrowed, could it be bent back?

 

[flecc]

At first sight, with only a centimetre each side to take up, a combination of spacers/washers and a slight fork tensioning inwards could be ok. That small amount of springing in after adding some washers wouldn't alter the forks, they'd just spring back as the wheel nuts were loosened.

However, the Tongxin motor uniquely has a two piece spindle which has had the odd failures, so it might be important that it's supported inboard by the forks close against the motor. Therefore I'd advise some expert opinion on this query.
.

 

[jerrysimon]

Can an 80mm motor be fitted without harm to a 100mm fork?

Thats the exact question I asked in another thread and another thing mentioned, was that you wouldn't want to bend them in too much if the fork faces were then not sitting square on motor/washer faces.

However, the Tongxin motor uniquely has a two piece spindle which has had the odd failures
.

I took my Suzhou Bafang SWXB hub apart when I replaced the motor and that has a two piece spindle which bolts on each side of the motor as well.

It seems Frank is the only place we can get the 80mm ones at a reasonable cost. Flecc is correct I have emailed Tongxin
a couple of days ago both from their web site and seperately and have yet to receive a response

Regards

Jerry

 

[flecc]

I've seen the figures of the 80 mm motor which suggest a peak output of 350 watts, but the 100 mm one had a previously published peak output of a little over 400 watts, so it seems there is some power difference which will be reflected in the torque as well no doubt. Not serious amounts of course.
.

 

[jerrysimon]

Another question. Can an 80mm motor be fitted without harm to a 100mm fork?

I just found this. Though its a transalation, I am not sure it is a definative answer

Google Translate

Jerry

 

[flecc]

I'd agree with a summary of those replies Jerry. Using nuts threaded on as spacers is preferable since if tightened they became spindle enlargers extending the load out to the frame.

I'm not entirely happy with spacers otherwise though, due to their two part spindle which is different from that Bafang one you mention, in that it's attachment arrangement is internal and much weaker. I prefer to see the support of the fork close to the motor bearings.
.

 

[jerrysimon]

Interesting Flecc I didn't understand that bit thanks for explaining.

I use washer/spacers with my Bafang and as I said that has a two part spindle but bolted fairly securely to motor alloy casing inside. I keep meaning to post some pics of it's inside.

Regards

Jerry

 

[apshamlton]

We have done extensive testing of the 80mm vs 100mm tonxgin motors and can supply both as part of our Freedom Ebikes kits.

Freedom E-Bikes - Home

The 80mm motor has about 10% less peak power but this is not significant in practice because peak power is only obtained from start up (ie low RPM).
Once you're moving the back EMF of the rotating motor limits power and the 100mm and 80mm motors perform almost identically.


Our Freedom Ebikes kits use the 80mm & 100mm versions of the tonxgin 36V motor combined with the latest nano-technology lithium batteries and some other design improvements to create what I believe is the world's lightest serious ebike kit. Its only 3.2kg (7lbs) including battery and I can testify that the battery is good for hilly city commutes up to 15km. The battery system is modular so extra batteries can be added for extra range if needed.

It also fits on the Brompton and other narrow fork folders without the need for new forks.

 

[AndyOfTheSouth]

Congratulations on your enterprise - it looks good.

Where are you based - would it be possible to collect a kit, for example? What speed motors do you use?

It will be very interesting to see how the business progresses. I particularly like the small, low weight battery approach. I wonder what other forum members think?

 

[daniel.weck]

What speed motors do you use?

The 36V Tongxin is a 180W 190RPM motor unit. Am I right ?

By the way, I do not want to cross-post, so just in case you've missed this message:

http://www.pedelecs.co.uk/forum/electric-bicycles/4642-nano-brompton-2.html#post59198

 

[daniel.weck]

Yes, I am using the 80mm Tongxin in my Dahon folding bike.
It is a 24V motor but I use it with 28V battery for a bit more speed.

Using the 24V Tongxin with a 36V battery and controller is a risky strategy. The maximum current draw should be set to a reasonable value (e.g. 10Ah, 30.5V, 80% power delivery). It also depends on the controller itself. My 36V Tongxin will be controlled by a e-Crazyman unit, not the original weak Tongxin controller. See here for details:

http://www.pedelecs.co.uk/forum/electric-bicycles/4682-diy-stage-1-received-bafang-tongxin-kits-photos.html#post59183

 

[RobinC]

We have done extensive testing of the 80mm vs 100mm tonxgin motors and can supply both as part of our Freedom Ebikes kits.

Freedom E-Bikes - Home

Looks interesting. Are you using standard Tongxin controllers? I notice you are putting these inside a Brompton bag so I might be concerned the standard controller would overheat. Since you also have outlets in Australia & Israel I guess they should be a good test ground for heat stress.

Robin

 

[apshamlton]

Hi Robin,
yes, we've tested the controller in the bag design in 35+ degree heat and it was fine under heavier than normal load.

The motors come in a range of RPMs to suit the various wheel sizes. We use 260rpm 80mm for 16" Brompton and 160 or 190 rpm 100mm for full size bikes.

 

[daniel.weck]

The motors come in a range of RPMs to suit the various wheel sizes. We use 260rpm 80mm for 16" Brompton and 160 or 190 rpm 100mm for full size bikes.

Shame I couldn't source 36V 260RPM 80mm Tongxin motors anywhere
(I have a 36V 190RPM 80mm, 180W ... which is very slow on a 16" wheel)

Are you selling them individually, or do you have minimum requirements as for how many components of the kit can be sold together ?

Regards, Dan
(in south-east England...where 35C never happens )

 

[apshamlton]

Hi Daniel, although we prefer to sell a complete kit because we've tested that everything works well together, we are prepared to sell individual components to hobbyists like yourself.
If you need a 36V 260 rpm 80mm Tonxgin motor then we can supply one.

Email me at: andrew@freedomebikes.com

 

[jerrysimon]

This all looks good. I can't even get Tongxin to reply to emails so its nice to see someone with the full range in stock being helpfull to hobbyists here.

On a 700c wheel I thought the preffered Tongxin was 175 rpm ?

Also is your single pack batttery 2300 or 4600 mAh, I am guessing 2300 given the low weight ?

Regards

Jerry