The Tongxin Motor thread

[frank9755]

[
Sorry to hear about your troubles, it sounds like a frustrating series of problems. When my motor died I was on a fairly smooth strectch of tarmac. The indicator lights stayed on &, later, I discovered that power stilled flowed to the motor and without load - wheel off the ground - it would spin under power, but nowhere near the rpm it should be spinning and no hope of turning with me on the bike.

In my 900 odd km of commuting I've hit some pretty nasty bumps, but not enough to lose control like you describe. My guess is that repeated thumps have caused a stress fracture that finally gave up. Actually it was pretty bad timing cos I'd just smoked a lycra clad guy on a regular bike and then had to suffer the humiliation of him passing me.

Interesting - thanks. Mine sounds different as it is completely dead, with wheel off the ground, wheel already spinning, etc - no noise or anything. A guy on the pedelec.co.uk forum was pretty sure that means its electrical not mechanical (ie the controller).

Bad luck on your timing! I use my bike for commuting in London along one of the main routes and there are dozens of road bikes going at 20mph+. With the Tongxin, for a few short days, I had their measure! But good luck on having support from a local dealer. You may have paid a mark-up for that but you are getting value for it now. Hope you're fixed up and back on the road soon!

Frank

[Timbo]

As an aside, there was a Vectrix on display in the shop. First chance I've had to check one out at close quarters. Sweet! I've been resisting the urge to take one for a test ride because I know I'll want one......

Resist! There are a few owners over on the V and they're having problems. Bad enough to the point to where they're considering ditching them and spending the money on something else.

Interesting. Where is this 'V' you speak of?? $15K is too much to spend if bad problems are likely.....

[Johnbear]

V =V is for voltage. http://visforvoltage.org. My second tongxin controller died today.

[Johnbear]

So I now have had a total of 33km of mileage on 2 controllers.

[Timbo]

Here's a quick update on where I'm at. Haven't been riding too much recently because of starting a new job & having to lug gear in the car and also some crazy hot weather. But I've put about 100km on the odo with the new motor & controller - both replaced gratis by EV.

Initially I was pleased that I seemed to be getting a bit more speed from the new equipment - like about 2-3 km/h - but I think it may be at the expense of range. Previously I could bet on 40km, maybe a couple more, but last weekend I ran out of go-juice at only 31. Luckily I was on the final straight & almost home, otherwise I would have been steaming!

Apparently there have been ongoing quality problems with the Tongxin and EV will be switching to another manufacturer shortly. Here's what Scott had to say in an email after I put him on to endless sphere and this thread in particular:

Thanks for this have read this one. These have been a bit of a nightmare for us. Great motor. Concept etc. Just too many quality issues. So we have a new motor we are moving to as of next container. However I have ensured all parts are available for your motor. Should you have another motor failure I will replace with the BF model. We have used the wider version of these for 4 years without any issues. 3 failure out of 200 units, so pretty good. Any how hope all is ok with your unit now. Stay in touch.

One of the other guys said that there had been some problems with earlier controllers and then went on to point out a date stamp on the back of the new controller: 080216, which I take to read as Feb 16 2008. If anyone's having controller problems maybe it's worth checking this.

[Freddyflatfoot]

Timbo,
That BF motor is really good! I have mine running at 36V, and it pulls really well. Have been 42 kph mounted in a 20" wheel. Had same motor in a 26" wheel, and it topped out closer to 50 kph, but with less torque.
It a bit heavier than the Tongxin though, at about 3 kg.
Dunno what my range is, haven't drained the battery yet, but have gotten 35 k and battery still feels strong, so I reckon I should get 40?
Anyway, interesting you say that Scott is pulling away from Tongxin. Maybe they could start getting the ezee motors!
As an aside, I am actually thinking of getting a small 24v front hub motor, to mate up with my 24v LiFePo4 pack, which is currently going unused!

[Mathurin]

Timbo uses item "Dran's Feather"! +3 increase to Spd! Lycra uses special move "Dash"! Lycra rolls attack die! 12 damage to Ego!

...

I honestly have no idea were that came from...

Pretty sure it starts with a P, ends with an n. EG:

[docnjoj]

Sorry but I had to stick in my 2 watts worth! Had an early Tongxin, went 4.5 miles and died! Used a Crystalite 20 amp controller and had mechanical failure of motor! Brett did the honorable thing and rep[laced it with a P2A, which is now going on 3.5 years ar 1000 mi/year! Tongxin sucks! My humble opinion! Brett is a Prince among men for his business practice!
Doc

[Johnbear]

I have a tongxin 3 controllers later it works, but poorly. The gear slips & the top speed is 20kph 12mph - after that it feels like you are pedaling a tank.

[fitek]

What's this p2a motor you speak of?

[Mathurin]

http://www.users.bigpond.com/solarbbq/P2-A.htm
"no longer available" May be possible to get a used one by asking on power-assist, tho?

[Freddyflatfoot]

There are other geared hub motors that are available that as good, if not better than the P2a.
Ezee comes to mind, as does Puma/BMC.
I personally use a BF motor from Suzhou Bafang P/L from China.
Feel free to contact Brett and solarbbq, he is very helpful.

[Johnbear]

After 3 controllers, the tongxin motor finally gave up. After taking it apart a bit it seems as though the ring that holds the press fit bearing is cracked. This motor and controller is crap. 2 thumbs way down.

[HTB_Terry]

The Tongxin motor is a good motor if used within specifications. It is the smallest and lightest motor out there, naturally it will not be as strong as a larger, heavier motor. It does have limitations and can not be abused. It is particularly good on smaller bikes where weight is at a premium. Schwinn uses this motor on their fullsized ebikes. They did make some improvements about 2 years ago. The weak point is a metal ring which compresses the roller bearings. If the motor is stressed beyond what it is designed for, the ring can develop a stress fracture around the mounting holes. This can be repaired however. We (http://www.hightekbikes.com) are a factory authorized and trained repair center for Tongxin and have the spare rings in stock along with the required tool to replace them. If anyone here has this issue, you can contact us (service@hightekbikes.com) to arrange to have it repaired, good as new. We also have spare controllers in stock. FYI, the new version of this motor is even thinner, and is sensorless for more efficiency. One note on the controllers, they are vulunerable to high levels of back EMF. If you go down a steep hill, the voltage generated by the motor will burn up the mosfets, I suspect because the internal diodes are conducting. The work around is to add some protection diodes on the three motor leads, to GND and Batt+. We have done this for several customers and have not heard back. Since this will pump the voltage into the battery, it will need to have over voltage and current protection (if Lithium).

[Johnbear]

The Tongxin motor is a good motor if used within specifications. It is the smallest and lightest motor out there, naturally it will not be as strong as a larger, heavier motor. It does have limitations and can not be abused. It is particularly good on smaller bikes where weight is at a premium. Schwinn uses this motor on their fullsized ebikes. They did make some improvements about 2 years ago. The weak point is a metal ring which compresses the roller bearings. If the motor is stressed beyond what it is designed for, the ring can develop a stress fracture around the mounting holes. This can be repaired however. We (http://www.hightekbikes.com) are a factory authorized and trained repair center for Tongxin and have the spare rings in stock along with the required tool to replace them. If anyone here has this issue, you can contact us (service@hightekbikes.com) to arrange to have it repaired, good as new. We also have spare controllers in stock. FYI, the new version of this motor is even thinner, and is sensorless for more efficiency. One note on the controllers, they are vulunerable to high levels of back EMF. If you go down a steep hill, the voltage generated by the motor will burn up the mosfets, I suspect because the internal diodes are conducting. The work around is to add some protection diodes on the three motor leads, to GND and Batt+. We have done this for several customers and have not heard back. Since this will pump the voltage into the battery, it will need to have over voltage and current protection (if Lithium).

That is what happened to mine. The metal ring that compresses the roller bearings cracked. At the time I was running a 36v 10amp controller I don't think I overstressed the motor. How much is the repair? I could mail you the motor. Are the replacement rings better than the stock rings? Thanks!

[HTB_Terry]

John,

The repair charge is $50 USD plus shipping. Locals can bring the bike or wheel by the shop. Obviously, for shipping the unmounted motor is best, but you can send the wheel. Our mailing address is on the website (Commerce Blvd). I assume Tongxin improved the ring as they were aware of the issue, but I don't have the details on the improvements. Stressing the motor would be a 200 pound guy going up a hill. 36 V at 10 amps is no problem. The controllers are rated at 15A. A comfortable load for this motor would draw 8-10 amps cruising on level ground.

Terry

[Timbo]

Timbo,
That BF motor is really good! I have mine running at 36V, and it pulls really well. Have been 42 kph mounted in a 20" wheel. Had same motor in a 26" wheel, and it topped out closer to 50 kph, but with less torque.
It a bit heavier than the Tongxin though, at about 3 kg.
Dunno what my range is, haven't drained the battery yet, but have gotten 35 k and battery still feels strong, so I reckon I should get 40?

What controller are you using? With the BF I'm getting extrodinary range - more than 50km - but my speed tops out at 26km/hr. I miss the wind in my face.

[Timbo]

John,

The repair charge is $50 USD plus shipping. Locals can bring the bike or wheel by the shop. Obviously, for shipping the unmounted motor is best, but you can send the wheel. Our mailing address is on the website (Commerce Blvd). I assume Tongxin improved the ring as they were aware of the issue, but I don't have the details on the improvements. Stressing the motor would be a 200 pound guy going up a hill. 36 V at 10 amps is no problem. The controllers are rated at 15A. A comfortable load for this motor would draw 8-10 amps cruising on level ground.

I think 'level ground' is a significant point. Although my commute was always on the road or sealed bike paths, potholes and uneven blacktop were an ongoing concern on rigid forks - sometimes they can't be avoided and I reckon that this stressed the first motor until it finally gave up - and the same thing was happening to the second. I weigh less than 60kg & used the thottle sparingly when setting off.

[Johnbear]

There are alot of hills here, a big reason I like my motor! But the tongxin cannot cut it. As much as I enjoyed the 4 times the motor worked, the 4 break downs sucked, riding 15km home with batteries was a bit heavy, but I made it. The tongxin may have a total of 150kms on it. My luyuan direct drive brushless motor has over 5000kms. My crystalyte over 1000km, various other direct drive motors roughly another 3000km. No problems with any of the motors except the tongxin.

[docnjoj]

I and my trike weigh> 300 lbs, so it is not surprising that the Tongxin failed! The Bafang has been excellent, but would not work well with Xlyte analog 20 amp controller! With Infineon it is wonderful!
otherDoc

[Johnbear]

The bafang is very tempting, I may buy one, I want at least on lightweight bike! Is it quiet?

[docnjoj]

Very quiet and I am a lunatic for quiet! At speed (> 8 mph ) u cant hear the gears. + 1 for Nylon!
otherDoc

[HTB_Terry]

The symptom for the cracked ring on the Tongxin is that you will hear the motor spinning, but the wheel doesn't turn. If you lift the wheel, it might turn slowly. No reason to junk the motor when it can be repaired. All readers of this forum will receive a 20% discount on the repair, so the cost is $40. If you have already opted for a bigger motor and want to sell the broken Tongxin, contact me.

One other thing to watch for is that the axle can bind on one side. If the nut gets loose on one side, the axle can spin. As someone mentioned, this motor has a split axle, the left and right sides are two different pieces so if one side turns and the other doesn't, the motor will jam. So if the motor quits, first loosen then tighten both nuts.

[The Stig]

Is there any chance things have changed now that 6 months have gone by. Any design changes? Anyone who has run the tongxin at 48v? 20A?

[The Stig]

Bump