WARNING: Begode T4 has shown the motor stator slippage issue, too! Sudden unexpected crash possible. Be aware and check yours.

[meepmeepmayer]

The T4 has shown the same motor slippage issue that the King Song S22 had. This can crash the rider when the motor suddenly falls apart internally during riding.

Read this topic or the topic linked below (including a link to the original motor stator slippage thread for the S22) for more and for how to identify a dangerous motor (motor labelled ZX):

Edited October 7, 2022 by meepmeepmayer
link fixed

[meepmeepmayer]

Some key quotes:

1 hour ago, supercurio said:

Sadly, I can confirm that the T4 is affected by the exact same stator slippage issue as the S22, as described in this post:

...

This results in an instantaneous cut-out and burns the mainboard. Alternatively, the hall sensor can be pulled off which on a Begode wheel (without sensorless motor control backup like the S22) can result in a cutout at any speed.

...

A riding buddy crashed and broke a finger within 700m of his first T4 ride this week due to this. So, better test before riding.

57 minutes ago, Biggane said:

I just received mine and it seems to have this issue. There’s a noise coming from the motor that sounds like metal rubbing on metal:

https://imgur.com/a/cOqNRA7

28 minutes ago, supercurio said:

Thanks for posting, that's the sound to look for on the T4.

The scraping sound is different than on the S22 and present itself as clicks, I guess against some pattern, but if you ride this your wheel will cutout quickly after, burn its board and send you to the ground.

Edited September 23, 2022 by meepmeepmayer

[Eucner]

So sad. Do Begode and KS have same motor supplier?

[meepmeepmayer]

I think yes, the motors labelled ZX seem to be the problem.

[supercurio]

Thank you @meepmeepmayer for creating this pinned topic!

[meepmeepmayer]

14 minutes ago, supercurio said:

Thank you @meepmeepmayer for creating this pinned topic!

Thank you for being the bearer of excellently presented bad news, once again

If you want to make a T4 topic akin to the S22 one, we can pin that and remove this one. But I figured you already said everything there is to say in your S22 topic.

[supercurio]

Haha yes always here to highlights problems to solve, and hopefully helping in the process 😄
I'm glad you're taking charge of this one, it's already a significant amount of work to drive the effort for the S22 motor.

I can recommend everybody with a T4 to ask their dealer about this issue. A bunch of them know now as we talked about it in the group focused on the S22 motor.

I'm trying to reach out to Begode as well in order to help fast-tracking their troubleshooting for the T4 motors, from lessons learned on the S22. Tips welcome.

[mhpr262]

It's utterly crazy that the stator just seems to have been attached to the hub with nothing but glue, no mechanically interlocking parts as a safety line at all. Just half a dozen small gear teeth on the hub and corresponding grooves in the motor stator around their circumferences would have prevented all that with 100% certainty. Some dude in front of a CAD program wanted to go home for the day and decided to just skip that part. The additional manufacturing cost would have been zero, as those parts seem to be cast, not machined.

Edited September 23, 2022 by mhpr262

[Nick McCutcheon]

1 hour ago, mhpr262 said:

It's utterly crazy that the stator just seems to have been attached to the hub with nothing but glue, no mechanically interlocking parts as a safety line at all. Just half a dozen small gear teeth on the hub and corresponding grooves in the motor stator around their circumferences would have prevented all that with 100% certainty. Some dude in front of a CAD program wanted to go home for the day and decided to just skip that part. The additional manufacturing cost would have been zero, as those parts seem to be cast, not machined.

My thoughts exactly. It's almost like you have to try to f*ck up this hard. I am astounded every day at the incompetency of these Chinese manufacturers.

[Eucner]

4 hours ago, mhpr262 said:

It's utterly crazy that the stator just seems to have been attached to the hub with nothing but glue, no mechanically interlocking parts as a safety line at all. Just half a dozen small gear teeth on the hub and corresponding grooves in the motor stator around their circumferences would have prevented all that with 100% certainty. Some dude in front of a CAD program wanted to go home for the day and decided to just skip that part. The additional manufacturing cost would have been zero, as those parts seem to be cast, not machined.

The cast parts are machined in a lathe for needed assembly tolerances. Teeth would have made it much more difficult to do. A pressure fit is appropriate method to join large diameter moderate torque round parts. Unfortunately it needs some attention to tolerances and temperatures. Glue alone is not enough under vibrations and shock loads in wide temperature range. The stator fitting seems to be tight enough for easy set screw fix. Permanent Loctite should be used to the screws.

[supercurio]

I don't have an answer on that yet (question asked) but there is so far no concrete evidence that glue (or lack thereof) was used for the stator assembly @mhpr262

The microscope view showed us the gap in the stator fit.

Maybe the interest on glue came from the video I linked in the original thread which showed the process of rewinding a tiny RC motor. I wouldn't to as far as extrapolating that EUC motors rely on the same solution tho 😄

Edited September 23, 2022 by supercurio

[Duf]

So excited my T4 with a ZX in the motor code showed up yesterday.  

[bracky72]

It’s a crappy situation but I’ve been riding mine.  So far so good.

 

Comparing it to my Nik Ar+ the power, speed and range is considerable less. But the ride is unlike anything I’ve experienced. It’s a bit disconnected feeling but that makes it so smooth. It took some experimenting to get the pressure right. I weight 175 and now have my psi at 200. Pretty good.

[Biggane]

That was way harder than it should have been, but I finally got my dealer to take back the T4. Good luck to all of you and thanks for quickly identifying the issue @supercurio!

Edited September 27, 2022 by Biggane

[Funky]

I knew it was crap.  Same as S20/22.

Keep testing those new lemons. I will enjoy older wheels, same as fine wine. 

Edited September 27, 2022 by Funky

[supercurio]

5 hours ago, Duf said:

So excited my T4 with a ZX in the motor code showed up yesterday.  

Maybe you can ask your dealer first to see if they're not too opposed to it, but the "landing test" as demonstrated by King Song for the S22 should be effective on the T4 motor too.

The failure rate on T4 motors already seems significantly higher than it has been with the S22, and since people already got hurt in crashes related I wouldn't recommend anybody to ride a T4 before at least trying to validate its motor.

I believe 100% of the T4 ZX motors wil have to be either replaced, or fixed like Russians have been doing with the S22.

@Duf, what about a video of the landing test on the T4? It's the perfect opportunity to combine EUCs and workout in a single activity 😅

Edited September 27, 2022 by supercurio

[zeuc.hu]

On 9/23/2022 at 2:59 PM, meepmeepmayer said:

I think yes, the motors labelled ZX seem to be the problem.

I had a cutoff yesterday because this issue. (Thanx god low speed, no injuries) Motherboard not burned - I can connect with begode app - but it shown: hall failure. Very new only 50km in my wheel. No noise before. Wheel not balancing anymore 

[supercurio]

@zeuc.hu glad it was without injury. I would recommend not turning the wheel on in vertical position, now that there's a problem with the hall sensor  .

Begode mainboards tend to self-destroy when the hall sensor is defective, turning the motor erratically and poof ⚡️

Edited October 5, 2022 by supercurio

[Robse]

The stator is fixed with a combination of pressure and glue - correct? Not that it helps anyone, but since these motors have been manufactured in the same way for many years (by ZX), i´ve got the idea, that the real culprit is the glue.  Something has changed - maybe a result of lockdown or supply chain problems?....  

[techyiam]

14 minutes ago, Robse said:

i´ve got the idea, that the real culprit is the glue.  Something has changed - maybe a result of lockdown or supply chain problems?....

Or, can the other possibility be that the hub material has switched from steel to aluminum alloy?

The V12's have ZX motors, but the hub is made of steel.

[supercurio]

@techyiam interesting theory, were the S22 and T4 ZX's first hollow-bore design? If so, then they failed their transition.

[Funky]

Or maybe because motors have gotten more powerful.. More torque.. They simply break "free".

[supercurio]

32 minutes ago, Funky said:

Or maybe because motors have gotten more powerful.. More torque.. They simply break "free".

Negative, C38 motors with 250A max of phase current from the controller like on the MSP or some newer wheels, depending on firmware version has significantly more torque applied on the stator interface than a C30 at 220A phase current limit as seen on these T4.

Edited October 5, 2022 by supercurio

[Eucner]

8 hours ago, Robse said:

The stator is fixed with a combination of pressure and glue - correct?

I don't know, but I would guess press fit only and problems with tolerances. Glues don't like hot places and impact forces.

8 hours ago, techyiam said:

Or, can the other possibility be that the hub material has switched from steel to aluminum alloy?

Could have a slight impact, but in the better direction. The higher thermal expansion coefficient of aluminium would increase pressure in the joint.

[techyiam]

15 minutes ago, Eucner said:

I don't know, but I would guess press fit only and problems with tolerances. Glues don't like hot places and impact forces.

Could have a slight impact, but in the better direction. The higher thermal expansion coefficient of aluminium would increase pressure in the joint.

Then continue the thought all the through the thermal cycles of heating up and cooling down over and over. And what happens to the stator assembly dimensionally. Does it cool down to its original diameter after being subjected to more hoop stress? Are they using the same glue? Can the glue handle the increase in thermal expansion repeatedly.