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GW MCM4 is Unsafe?


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Today @h00ktern & I took the MCM4 & KS14 out to a park to do a range test of the Wheels. Both Wheels were fully charged, I was on the MCM4 (I am about 70kg). We were cruising around the 22-25k

Well, I need to chime in on Jason's behalf... I have ridden with him the past three weekends, and am lucky to have gotten to know him in that time. He is extremely intelligent, and passionate about pu

Jason definitely goes above and beyond to research the euc behavior at his own risk, and shares his knowledge with the community. Most of us dont, we prefer to ask questions on the forum, in the comfo

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Good luck with your injury that the skin comes back fast.

But let me say I'm not happy with such a sentence when a KS distributor tell such a story about a competitor product. Even if you hurt yourself and if the story is true (why not) but it has a bad taste. That's the first report on this issue. So never install a 9b1 firmware on a Gotway ;)

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45 minutes ago, OliverH said:

That's the first report on this issue. 

I'm an independent distributor & can stock any brand I want. The point of the exercise was to evaluate if the MCM4 was any good for distribution. To advertise an operating speed of 35kph & cut-out at 25kph under perfect conditions, is in my opinion, not acceptable—like it or not, those are the facts. 

At the time was recording the run on a ActionCam, but the impact stopped the recording & the last critical couple seconds were buffered & not recorded to flash. At least it gives the viewer a sense of the speed to avoid... 

https://www.youtube.com/watch?v=yVChVQIq5yM

On another thread, these four users also report MCM4 cut-outs under normal conditions. edwin_rm, Dominique B., Jurgen, Swissfonda

 

 

Edited by Jason McNeil
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@Jason McNeil, i am very sorry to hear about the nasty fall. Looking at those pics makes me want to wear wrist guards, which i havent been. Hope you can get better soon

the downfall of the wheels is there is no safety based on the redundancy in eucs. Only 1 tire, 1 motor, and any fault be it electrical or mechanical or any other will cause a fall. Its good to keep track of these accounts of the wheels cutting out so that the design can be perfected and people are forewarned

no wheel is totally safe for that matter - there have been a few reports of kingsong cutting out too, sadly.

Just watched the video...why was the wheel beeping like crazy though? It sounds like it was saying : slow down? Should this beep be on at 25kph?

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2 hours ago, OliverH said:

Good luck with your injury that the skin comes back fast.

But let me say I'm not happy with such a sentence when a KS distributor tell such a story about a competitor product. Even if you hurt yourself and if the story is true (why not) but it has a bad taste. That's the first report on this issue. So never install a 9b1 firmware on a Gotway ;)

While one person's better experience with one brand over the other cannot be used as statistical evidence, i can't blame Jason for praising kingsong over gotway is this particular instance. Both brands have had cutouts, but if i had just fallen off , say, kingsong,  id be cursing out the brand and would probably be in the mood to say its the worst brand in the world as opposed to another one i hve never had a problem with. I personally dont know which brand is more prone to cutouts but we are all human and hve an affinity to generalize based on personal experience.

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Jason, wish you fill less hart now. 

In power electronic design practice, the control part and the driving part are always separated, photocouplers are used to passing the control signals. Not only having it own power supply, the controller is usually in a sealed steel box to prevent external electromagnetic interference. 

Unfortunately, EUs cannot afford this kind design now.  A strong electric noise spike may cause the control board reboot or lock-up. 

Wish a few generations later, a high end EUs can have a more reliable design, at least use a small battery (or a super cap) to keep it working uninterruptedly. 

Edited by Jimicycle
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OUCH! Sorry to hear about this Jason. I wear a pair of fingerless gloves and they've saved the palms of my hands a couple of times. That's a pretty tough spot to have road rash, but you might try either Tegaderm or a Manuka Honey bandage. I've used both and they will stop any scarring without being really bulky or annoying like gauze.

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Ouch!! I wish you a very quick recovery!

 

One main point to take from this...

Wear the necessary protection regardless of which wheel you ride! I've made a point to put on every piece of protection every single time.. and that's for a "hover"board! EUCs go way faster and everyone should take care to protect themselves.. just in case! I'm just glad it was only skin coming off this time, Jason!

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I posted the following back in November 4th.  This wheel is not made to go faster than 20 km/h.  If it shuts down at 28 km/h under no load (lift test) it is not surprising for it to cut out on you at around 25 km/h if you had the over-speed tilt-back disabled.  Wish you a speedy recovery!

Quote: MCM4, at the highest speed tilt-back setting, tilts back at 20 km/h (inflated to "24 km/h" in the app).  In a lift test the motor shuts at 28 km/h ("33 km/h" in app).  With KS14-800W the motor shuts at 41 km/h in the same lift test.  Tilt can be programmed in at as high as 32 km/h with the app.  These are the hard figures.  I don't want to burn any bridges but I'll just say that I am not keeping my MCM4.

Original comment link:
http://forum.electricunicycle.org/topic/1566-photo-gotway-mcm4-vs-king-song-14-inch-800w-physical-comparison/?page=2#comment-17706

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Has anyone successfully "run off" a euc at around 25 km/h for whatever reason?  Just wondering if it's the "unexpected" factor that causes the inability to run off or is 25 km/h just too darn fast to run off in the case of a motor shut down?

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12 minutes ago, John Eucist said:

I posted the following back in November 4th.  This wheel is not made to go faster than 20 km/h.  If it shuts down at 28 km/h under no load (lift test) it is not surprising for it to cut out on you at around 25 km/h if you had the over-speed tilt-back disabled.  Wish you a speedy recovery!

Quote: MCM4, at the highest speed tilt-back setting, tilts back at 20 km/h (inflated to "24 km/h" in the app).  In a lift test the motor shuts at 28 km/h ("33 km/h" in app).  With KS14-800W the motor shuts at 41 km/h in the same lift test.  Tilt can be programmed in at as high as 32 km/h with the app.  These are the hard figures.  I don't want to burn any bridges but I'll just say that I am not keeping my MCM4.

Original comment link:
http://forum.electricunicycle.org/topic/1566-photo-gotway-mcm4-vs-king-song-14-inch-800w-physical-comparison/?page=2#comment-17706

Wow, that's huge. Why would the MCM4 claim a much higher top speed then? I'm so glad then that I decided not to buy a MCM4 but the decision was taken based on the pedal issues.

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12 minutes ago, John Eucist said:

 Has anyone successfully "run off" a euc at around 25 km/h for whatever reason?  Just wondering if it's the "unexpected" factor that causes the inability to run off or is 25 km/h just too darn fast to run off in the case of a motor shut down?

Yea I saw  @Pagsy run off close to this speed but it wasn't a motor shut down. It was a bump that did it.

Edited by logos122
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17 minutes ago, John Eucist said:

I posted the following back in November 4th.  This wheel is not made to go faster than 20 km/h.  If it shuts down at 28 km/h under no load (lift test) it is not surprising for it to cut out on you at around 25 km/h if you had the over-speed tilt-back disabled.  Wish you a speedy recovery!

Quote: MCM4, at the highest speed tilt-back setting, tilts back at 20 km/h (inflated to "24 km/h" in the app).  In a lift test the motor shuts at 28 km/h ("33 km/h" in app).  With KS14-800W the motor shuts at 41 km/h in the same lift test.  Tilt can be programmed in at as high as 32 km/h with the app.  These are the hard figures.  I don't want to burn any bridges but I'll just say that I am not keeping my MCM4.

Original comment link:
http://forum.electricunicycle.org/topic/1566-photo-gotway-mcm4-vs-king-song-14-inch-800w-physical-comparison/?page=2#comment-17706

If that's true looks like Gotway is trying to pass off a cheap generic unicycle as a higher end unit.  Ugh

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23 minutes ago, playdad said:

Wow, that's huge. Why would the MCM4 claim a much higher top speed then? I'm so glad then that I decided not to buy a MCM4 but the decision was taken based on the pedal issues.

Yeah I was hyped up and then disappointed.  The pedals also scrape the floor doing tighter turns.  Increasing the "V" angle for the set of pedals by placing a material on the hinge helped a bit.

20 minutes ago, logos122 said:

Yea I saw  @Pagsy run off close to this speed but it wasn't a motor shut down. It was a bump that did it.

That's the thing.  I'm thinking MAYBE a bump or pothole makes it easier to run off because the jolt instantly alerts you.  Perhaps a motor shutdown is too "smooth" so you don't have time to react.  Just speculating.

21 minutes ago, BA-B8 said:

If that's true looks like Gotway is trying to pass off a cheap generic unicycle as a higher end unit.  Ugh

Yeah I dunno.  Some say the normal MCM4 is high torque.  @Verachai Chanthabunloet claims he has a "high speed" version that goes 45 km/h and tested at 42 km/h so I dunno.

Source: https://www.facebook.com/groups/ElectricUnicycle/permalink/914390371992260/

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9 minutes ago, John Eucist said:

That's the thing.  I'm thinking MAYBE a bump or pothole makes it easier to run off because the jolt instantly alerts you.  Perhaps a motor shutdown is too "smooth" so you don't have time to react.  Just speculating.

That actually makes a lot of sense. Riders are actually pretty alert and can feel everything through the legs. The sharp feedback from a hole or sharp bump probably alert you enough and trigger the instinct to do a last second save. I've had that happen several times even though I could not anticipate something was going to happen.

 

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11 hours ago, Cloud said:

While one person's better experience with one brand over the other cannot be used as statistical evidence, i can't blame Jason for praising kingsong over gotway is this particular instance. Both brands have had cutouts, but if i had just fallen off , say, kingsong,  id be cursing out the brand and would probably be in the mood to say its the worst brand in the world as opposed to another one i hve never had a problem with. I personally dont know which brand is more prone to cutouts but we are all human and hve an affinity to generalize based on personal experience.

The Ninebot One has so many failures but nobody generalized it as totally unsafe. The thing is it might be only this unit that has a mechanical defect which is just the same argument of the Ninebot One owners. Generally speaking, riding a single wheel motorized vehicle at 25km/h is considered unsafe and should be done only with full protective gears. 

@Jason McNeil Sorry to hear about your injury and hope for your fast healing .  

Edited by SlowMo
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13 hours ago, OliverH said:

I'm not happy with such a sentence when a KS distributor tell such a story about a competitor product. Even if you hurt yourself and if the story is true (why not) but it has a bad taste. That's the first report on this issue.

When I met Jason to purchase my wheel it was a toss up between the KS-14 and an IPS wheel, both of which Jason stocked. He did not push me in the direction of either wheel and, actually, it is what I'd previously read and studied on this forum that decided me on the KS (so thank you all for your brilliant input here :-) ).

I would agree with OliverH that it is only one example and it could be a one-off fault, but that is no reason whatsoever for someone with Jason's skill and experience not to report on it on his forum, indeed quite the reverse.

One other lesson comes out of this as well: even the best of us can get hurt. If you are going faster then you can run (probably about 5kph in my case :-{ ) protection is a very good idea.

Have a happy and safe holidays everyone.

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