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GW MCM4 is Unsafe?


Jason McNeil

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On 12/25/2015 at 10:51 PM, John Eucist said:

Thanks for sharing that video.  It didn't look uphill though?

It wasn't too uphill, maybe 20-25% grade or 15 degrees. However, I'm about 180cm and 75kg, so it's a little too easy to torque it.

 

I added more details to that original post (on page 2 of this thread) as to how I fell, if anyone's interested. If I have time I'll try to make a dedicated thread for it.

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5 hours ago, csmyers said:

It wasn't too uphill, maybe 20-25% grade or 15 degrees. However, I'm about 180cm and 75kg, so it's a little too easy to torque it.

 

I added more details to that original post (on page 2 of this thread) as to how I fell, if anyone's interested. If I have time I'll try to make a dedicated thread for it.

Strange.  It looked like flat or at most 5 degrees.  Must be an optical illusion heh.
https://www.youtube.com/watch?v=_svdD0f1reE

 

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On 24. Dezember 2015 at 6:16 PM, Jason McNeil said:

Thanks everyone for your kind words:D Maybe my assessment of the MCM4 is wrong & I received a wonky Wheel. What I don't understand is that (as Gimlet said) the older MCM2 had a considerably higher cut-out speeds than GW's new flagship product (QC tag is only 3 weeks old), which was in development for months. How can you make a Wheel slower, with less power safety margin than the previous generation?! I'm not trying to denigrate the brand, the MSuper is of course a much safer Wheel & GW were the first to introduce many firsts, but from my painful experience, they need to improve the safety of this model. 

The irony is that because my knees were also bashed up, I'm more dependent on the Wheel than ever for getting around. Obvious conclusion people draw when they see me bandaged up is that it is the Wheel that I'm riding (or even worse, the irresponsible rider!) is intrinsically unsafe. I've been riding for nearly 2.5 years & although the early IPSs had a much lower cut-out threshold, the speed was sufficiently low that running off was a certainty. 

 

We got note in the German G+ eWheels.org usergroup that a German MCM2 rider got such a cut out: 2 damaged teeth, lips damaged, arm broken. He was driving at 27 km/h at the limit and was catched by physics and a bad control system from Gotway. With a proper tilt back you can set this riders a limit which works. But you need someone programming it into the firmware.

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8 minutes ago, OliverH said:

We got note in the German G+ eWheels.org usergroup that a German MCM2 rider got such a cut out: 2 damaged teeth, lips damaged, arm broken. He was driving at 27 km/h at the limit and was catched by physics and a bad control system from Gotway. With a proper tilt back you can set this riders a limit which works. But you need someone programming it into the firmware.

I wonder why people need to drive to the limits. Cars have limits but has anybody here driven all the way to the max available speed of their car? Be safe, drive moderately. Otherwise this hobby will be considered dangerous by authorities and might be totally banned.

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I have a park dedicated to bicycle close to my house. Is it possible to drive @30km/h if your wheel can reach safety that speed. 

The issue with GW that they communicate on safety and engine power but the original version was not at the level. I hope the new version "High Speed" is better.

 

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5 minutes ago, SlowMo said:

I wonder why people need to drive at the limits. Cars have limits but has anybody here speed all the way to the limit of their car? Be safe, drive moderately.

Limits are good. My car is also limited to 260 km/h ;)

Seeing the new wheels hitting 40 km/h I think we'll get bad reputation. The first heavy crash resulting in a rider sitting in a wheel chair or a death rider will put us on the first page in newspapers. I'm more a safety guy and would nail it down to 20/25 km/h

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On the french forum we have the first feedback of mcm4hs owner:

The link in french of course : 

http://trottinetteselectriques.heberg-forum.fr/ftopic2663_compte-rendu-nouvelle-mcm4-hs-high-speed-quot.html

Improvements:

Pedals raised: no more problems for tight curve.

New shell: the tire do no touch anymore even in high pressure. Longer and more comfortable side pads

Speed : some owners have reach 35 km/h but... you can only set the tiltback to max 24km/h in the app . If you want want to go faster you must desactivate it ! 

Just like the mcm2 in high speed you  only have the bips and at  last the final cut out ... the safety policy of gotway is totaly incomprehensible...

 

 

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12 minutes ago, Philfree said:

On the french forum we have the first feedback of mcm4hs owner:

The link in french of course : 

http://trottinetteselectriques.heberg-forum.fr/ftopic2663_compte-rendu-nouvelle-mcm4-hs-high-speed-quot.html

Improvements:

Pedals raised: no more problems for tight curve.

New shell: the tire do no touch anymore even in high pressure. Longer and more comfortable side pads

Speed : some owners have reach 35 km/h but... you can only set the tiltback to max 24km/h in the app . If you want want to go faster you must desactivate it ! 

Just like the mcm2 in high speed you  only have the bips and at  last the final cut out ... the safety policy of gotway is totaly incomprehensible...

 

 

I read this report yesterday night.

I think they could fix the tilt-back issue with an update of the new coming software IOS.

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13 minutes ago, Nono said:

I read this report yesterday night.

I think they could fix the tilt-back issue with an update of the new coming software IOS.

Why participate on a field test/ beta program and pay the full amount? Banana products - getting ready at the customer.

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50 minutes ago, Philfree said:

On the french forum we have the first feedback of mcm4hs owner:

The link in french of course : 

http://trottinetteselectriques.heberg-forum.fr/ftopic2663_compte-rendu-nouvelle-mcm4-hs-high-speed-quot.html

Improvements:

Pedals raised: no more problems for tight curve.

New shell: the tire do no touch anymore even in high pressure. Longer and more comfortable side pads

Speed : some owners have reach 35 km/h but... you can only set the tiltback to max 24km/h in the app . If you want want to go faster you must desactivate it ! 

Just like the mcm2 in high speed you  only have the bips and at  last the final cut out ... the safety policy of gotway is totaly incomprehensible...

 

 

Is that real 35 km/h or "Gotway App 35 km/h"?  They typically inflate about 20% in the app compared to real speed.  The "24 km/h tiltback" in the app is really only 20 km/h in real life.  Also, is the "pedal raised" actually raised or just the ANGLE raised (more "v") or both?

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They launched the original version in november earlier for sure ; the HS version for X-mas.

But, they seem have heard the customer needs and the main criticisms...

I loved my Gotway MCM2s... I have to go to Paris and Bordeaux (FRANCE) in couple days and I decided to test this wheel...

I will make my own opinion... I discussed with a french dealers ; They tested it and Max real speed 27-28km/h with tilt-back. They are on vocation at the moment... wait and see...

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3 hours ago, SlowMo said:

I wonder why people need to drive to the limits. Cars have limits but has anybody here driven all the way to the max available speed of their car?

This is relatively easy to explain. (a) in contrast to EUCs, the limits of most cars are far beyond of what is easy to push. (b) most of the times cars are used as means to the end. 

I believe I would find myself consistently pushing the limits if my EUC had a max speed of 12km/h. Not so much for 22km/h anymore, but that's just my personal preference.

2 hours ago, Philfree said:

Just like the mcm2 in high speed you  only have the bips and at  last the final cut out ... the safety policy of gotway is totaly incomprehensible...

My MCM2s exhibits a pronounced change in behavior, namely a softening (only "tested" in madden mode), when pushed towards the limit. 

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1 hour ago, Tomek said:

@Jason McNeil do you have a theory about the reason of your crazy cut-off? was it the battery issue (wonder what cells does GW use), or the controller hardware/firmware issue?

Good question. A datalogger connected to the battery pack is an effective means of diagnosing insufficient power issues. I can only speculate, but from chatting with John Niem, who has also owned a MCM4 at one time, leads me to believe that it's more likely a case (that despite advertisement claims to the contrary) the motor is wired for torque & stalls out around the 25kph range. 

The MCM4 I had was the 680Wh model, there ought to be plenty of reserve power to maintain that cruising speed...

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3 minutes ago, Jason McNeil said:

Good question. A datalogger connected to the battery pack is an effective means of diagnosing insufficient power issues. I can only speculate, but from chatting with John Niem, who has also owned a MCM4 at one time, leads me to believe that it's more likely a case (that despite advertisement claims to the contrary) the motor is wired for torque & stalls out around the 25kph range. 

The MCM4 I had was the 680Wh model, there ought to be plenty of reserve power to maintain that cruising speed...

If it's wired for torque, you could have just reached the maximum speed for the voltage. If the driving bridges cannot give higher voltage than the back-emf generated by the motor, the motor cannot run any faster (AFAIK).

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1 minute ago, Jason McNeil said:

Good question. A datalogger connected to the battery pack is an effective means of diagnosing insufficient power issues. I can only speculate, but from chatting with John Niem, who has also owned a MCM4 at one time, leads me to believe that it's more likely a case (that despite advertisement claims to the contrary) the motor is wired for torque & stalls out around the 25kph range. 

Hmm, that probably means that the more recent MCM4 HS version with max speed @35km/h (read - stall speed) and tilt-back fixed at ~22km/h is what the "basic" version should have been from the start.

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Just now, esaj said:

If it's wired for torque, you could have just reached the maximum speed for the voltage. If the driving bridges cannot give higher voltage than the back-emf generated by the motor, the motor cannot run any faster.

Exactly as Esaj says, once you're on the right side of the operating window of the motor's design speed, you're in trouble. There's definitely a correlation between the lift-cut-out rotational speed & the cut-out-speed while riding. 

http://lancet.mit.edu/motors/colorTS2.jpg
colorTS2.jpg

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are there any known cases of cut-offs on the new MCM4 HS models? from what I read (and as annoying and irresponsible as it is that GW has initially released a seriously buggy wheel) it seems that the new HS model solves all serious problems of the first release (except the unchanged low max tilt-back speed)... 

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20 minutes ago, Tomek said:

are there any known cases of cut-offs on the new MCM4 HS models? from what I read (and as annoying and irresponsible as it is that GW has initially released a seriously buggy wheel) it seems that the new HS model solves all serious problems of the first release (except the unchanged low max tilt-back speed)... 

Don't buy the MCM4 it will not be safe with your riding style.

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too late, it's on its way, I acted on an impulse .') I like to ride on the safe side though and am ok with a tiltback at 20km/h (unless it's for testing, when properly geared up)

@SlowMo I thought you (and your wife) were happy with yours?

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54 minutes ago, Tomek said:

too late, it's on its way, I acted on an impulse .') I like to ride on the safe side though and am ok with a tiltback at 20km/h (unless it's for testing, when properly geared up)

@SlowMo I thought you (and your wife) were happy with yours?

Yes we are. It's now our favourite. Hope you will like it too because there's no turning back now. :D

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On December 25, 2015 at 8:26 PM, csmyers said:

EDIT: Watching the video in slomo shows my foot touched the ground but my forward momentum carried my upper body over. So my right foot touched down, then my right arm/shoulder hit the ground as I curled up. After I rolled across from my right shoulder blade to my left hip, I used my left leg as a lever to disperse my momentum and turn horizontal momentum into upwards momentum so I could stand up. Of course I didn't actively think of these steps, but I've trained my muscle memory to do this.

I have a couple years of experience falling off skateboards at high speeds (downhill longboarding) so I've practiced the art of falling. I would suggest everyone do the same...

Video is terrible quality and it cuts out before I am able to get up, but you can see in the last frame that I'm basically already up.

https://www.youtube.com/watch?v=_svdD0f1reE

Do you have any tips on how to train to bail out of falls? That is a well executed roll. 

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When my son (test pilot) is testing upper limits of wheels he always rides with slightly bent knees rathe than locking them out straight. This is how he is able to run off high speed failures without the use of falling techniques.

He still has the odd fall when riding normally day to day though.

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