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WARNING! Gotway ACM V2 / Monster PEDAL BREAKAGE Incident


houseofjob

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18 minutes ago, EvenOdd said:

My ACM will be here Wednesday. I guess I won't be jumping any curbs :(. Sucks because I jump up and down them all the time with my IPS191. 

With the Monster breakage (it uses the same pedal design as the ACM), I was later able to observe how he rides the Monster, and his feet are on the outside of the pedal. I think that contributed to the break because of the added leverage on the pedals.

When I ride my Monster and ACM, my feet are against the body of the wheel so I think there's a lot less stress on the pedals since your feet are much closer to the pivot point of the pedal.

If that's how you also ride you probably won't have any issues. There are only two known breaks - I don't think you have much to worry about.

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6 minutes ago, Marty Backe said:

With the Monster breakage (it uses the same pedal design as the ACM), I was later able to observe how he rides the Monster, and his feet are on the outside of the pedal. I think that contributed to the break because of the added leverage on the pedals.

When I ride my Monster and ACM, my feet are against the body of the wheel so I think there's a lot less stress on the pedals since your feet are much closer to the pivot point of the pedal.

If that's how you also ride you probably won't have any issues. There are only two known breaks - I don't think you have much to worry about.

Thanks for the info, Not sure how I will ride with the ACM...on my IPS the pedals are not very wide, so my feet are close to the body. I imagine I will continue to ride like this since I'm used to it. 

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On 3/29/2017 at 11:59 PM, meepmeepmayer said:

Do you have any more details on that? Did it happen to your wheel?

Not mine, but another russian euc community hardcore winter rider :). Here's the disassembly video, he found it at the end 

 

A

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  • 1 year later...
On 3/13/2017 at 5:55 AM, captainwells said:

Not any more!

One of the pedals broke off of my Monster today when I dropped off a standard 6" curb.  I ran it off with no injury.  My riding weight is 82 kg.  I got the Monster a month ago and have put 518 km of mostly paved bike paths on it.  There are no stress fractures or visible signs of distress on the other pedal.

 

I've been riding for 1.5 years and have hopped countless curbs.  My knees were bent and I always try to land as softly as possible.

 

I think that might be the problem.  I'm not sure what kind of alloy this is, but it doesn't look very strong at all and there are numerous little air bubbles.

 

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Thanks for quality pics, these say a lot!

I think everything from the material choices to the forging process itself bare some blame here, heck I say design is too weak to begin with especially knowing you will use the cheapest China alu alloy you can possibly get your hands on for next to nothing, you can even see the dirt in the alloy as well as unacceptable amount of air trapped in the forging process, although could also be from burning out non metallic crap that does not belong in the alloy leaving these hollow rooms. I do work with metals but not an expert on any of the casting techniques used so leave that up to someone else to determine exactly what we are looking at?

I don't know how to translate it but for sure this is what we would call a "smutsig legering", translates directly to something like "dirty alloy" but surely the English speaking nations have another word for it and it is true, this is not a clean alloy I don't need a electron microscope to tell me that, material fatigue in combination with choosing a dirty alloy like this and perhaps not a superb design to begin with..? If anyone of you have got free access to electron microscope please send a piece there and post the results would be very interesting nevertheless?

I mean even a standard 6005 aluminum alloy is not that expensive, will be over 97% aluminum, a pinch of iron, copper, zink, silicon etc and tensile strength of some 200MPa or more and strength would go up quite a lot from just that material choice alone using same design and molds. Normally you go hollow (weight and cost savings) where you can and solid and strengthen at/near attachment points where the load is, if not fully solid at least much thinker walls and a good design where majority of the force is applied. Would also look much cleaner and uniform when braking a 6005 alloy looking at the exposed area.   I was always  worried about the pins holding the pedals to the arms, but seams I should not now I need to consider the whole shebang hehe, jokes aside minimum inspections every now and then for cracks or beginnings of material fatigue (which could for ex look like tiny lines along the surface where the force is applied, almost like micro cracks.)

Yes could be localized incidents, but still not what you want to see.

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@Electroman it's not an isolated incident, we've had riders here in NYC break or show signs of breakage on their ACM-style pedals.

They're just not engineered very well, to little structural support, combined with being too wide (i.e. distance of the pedal perpendicularly away from the EUC body), which creates more torque on the pedals themselves.

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24 minutes ago, houseofjob said:

@Electroman it's not an isolated incident, we've had riders here in NYC break or show signs of breakage on their ACM-style pedals.

They're just not engineered very well, to little structural support, combined with being too wide (i.e. distance of the pedal perpendicularly away from the EUC body), which creates more torque on the pedals themselves.

Thanks, suspected just did not want to go there pre mature.

I believe understand what is happening to the pedals in terms on breaking down, just not the language to express it. My English is not too bad, well I suppose that is relative too but it is indeed limited. Great explanation, thanks.

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  • 4 weeks later...
On 2/25/2017 at 2:38 PM, Pingouin said:

How is this possible, the footplates are metal but they look plasticy on these pictures..

Scary if this happens at high speed, I'll check them before each ride from now on, thanks !

Very good decision, I will start doing it to even though on the Msuper pedals (I have the ACM too so) cause in my experience a company like Gotway will follow same design language, use the same cast Aluminum and likely only very small estetic differences as possible all in the name of cost savings and not having to redesign a full pedal from scratch. Besides I highly doubt Gotway do any real simulations on tensile strength over a pedals life time, these types of companies do not operate like this imho it's too expensive of a process.

Very good spot (especially if not working with metals at all), the grainy edges do indeed make it look a bit like plastics, but just case of the casting alloy and process and on top of that a dirt quality alloy, not very clean.

Hard to say, Alu is classified and treated in a number of ways to reach desired result and I often let the eye fool me about compositions and I work the field + the wrought and cast Aluminum number designating system will reveal there is a ton of information to extract here in regards to workability, weldability, tensile strength and just behaviour of the alloy ion general etc.. and  on top of all this we have quality which is not even baked in here. It goes something like xxxx for wrought and xxx.x for cast Alu where first number reveal what main element it's alloyed with, 5xxx would be the one for Magnesium, 6xxx the one for Magnesium and Silicon but I reserve myself to be wrong here, memory is not what it used to be I suppose and somehow seam to get worse with every year haha..

 

Regarding that quality..

China almost always = lesser quality, now I understand not everyone want to hear this but I should know, our company deliberately choose not to go there.

US = higher quality (I am in the EU), we have quality here too I say us cause they are big here and got some mighty knowledge in regards to Alu alloys

There's Alu alloys stuffed together world wide, like places such as South Africa and Russia and believe it or not the Russians actually know this material well and not too expensive, hint hint Gotway.. :)

Ohh there is an exception from first number being alloy element and that is 1xxx Alus cause 1xxx = minimum 99 pure, raw Alu so we start to move away from alloys here. Rest of numbers are arbitrary (like series info etc) and there also a temper designation system to follow the numbers but I but I admit I do not have it in memory, if need to check up on this I go check when need to do so.

On 2/25/2017 at 7:31 PM, One said:

Looks like they are made of magnesium - same material used in skateboard axes. Had some of them broken and it looked similar. No fun, even at lower speed... 

My knowledge does not stretch as far as to skate board axis I must admit, but I good point there should be something to lean here since skateboards have been around for some time and been popular, hence should have rooted out worst problems with designing light and durable axis

On 2/25/2017 at 8:55 PM, Mono said:

probably an aluminium-magnesium alloy, no?

Could very well be, again this would make it 5xx.x something (possibly a 6xx.x), or perhaps you think of a hybrid in which case I am clueless and don't listen to me hehe.

Ohh I forgot so edit:  If this is indeed a 5xx.x alloy welding is possible, if you know how the typical (but not all) diamond plates feel and is to work with then you likely know about something like EN AW 5754 H144, A quality found in industrial spaces with quite a aggressive environment even and a bit all over. But comparing to the Gotway pedal I would say no, probably not but then again I have yet to see one cracked open all I see is the treated surfaces of the pedal and I am no expert in Aluminum so could not tell? If this is China's answer to 5754 H244 it is much worse then I first imagined, cause those feel very though to work with just put an angle grinder to it cutting it will realize the cutting disks are eaten up fast, do not crack to easy and bend way before it crack if forced to.

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