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Potential problem with Master (and other Begode Suspension wheels) shock Bridge


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Yeah yeah, I don't enjoy creating these topics, I have had so many problems with my Master it's not funny, it's currently disassembled and waiting for below replacement part.

Update 1: People have been pointing out that changing suspension geometry might put less stress on this part but I changed geometry before even going on the first ride, I have Kuba/Torque links with a Rockshox Monarch RT3 at 210PSI and suspension wasn't always stiff it came over time.

Update 2: Kebye Gotway has responded on my Facebook post that they will improve this part.

Background:

I noticed in the past month that my suspension system was pretty stiff no matter what I did to tune it, I disassembled it twice to check every moving part, bushings, etc, after many hours of troubleshooting I discovered that each suspension piston (left and right side) moved fine with minimal friction on their own on the suspension pipes but once I connected both of the via the bridge that holds them together there was a lot of friction which was very odd.

Finally I investigating the bridge closer and it looked like it had some flex in it causing the two pistons to not be straight, this is something that must have happened over time because my suspension was not like this before.

Note: Due to various problems with my Master I have not ridden it a lot and I have not done any extreme riding, I have done some stairs at most but not a lot of stairs riding either, so this wheel has not been abused or stressed.

So with both pistons attached to the bridge I put some gentle force with my hands on it just trying to see if I could flex it back in the other direction a little bit, I wasn't really pushing hard when the whole thing just bent and cracked! As you can see the areas that broke are both very very thin.

bridge1.thumb.jpg.8a25847e4155fa8eb928e7b475ec5efd.jpg

20230114_110857.jpg.475d26986413260100dd64e33f336adc.jpg20230114_110905.thumb.jpg.20c5e1ac1e9859795307260fc651dae7.jpg20230114_110911.thumb.jpg.142afe72d9e12ad48d2ec400619998ef.jpg

While waiting for the replacement part it got me thinking how it would flex in the first place, well knowing these weak-points and thinking about how the suspension works it's not difficult to imagine the forces at play that could have caused this:

bridge2.thumb.jpg.4b71eb4bc2f38318f5b8e021f65d9ca2.jpg

So if your Master or other Begode wheel with similar suspension system feels very stiff and you can't find the problem no matter how much you try to tune it this might be why.

Edited by Rawnei
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Looking at Master X teardown at ecodrift it's difficult to see but it appears to be the exact same bridge on this model:

https://ecodrift-ru.translate.goog/2022/10/24/master-x-razbiraem-plus-video/?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=sv&_x_tr_pto=wapp

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Just now, bracky72 said:

I notice it’s on the side that only has two bolts attaching the fork.  This had looked like a weak point to me. 

Yes exactly, as you can see both the side with the screws and the other side that has a cable channel are both very very thin

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Time to contact the Russians! Their aftermarket CNC made parts should offer a better fix to this problem, after all, replacing one broken Begode part with another may be described as being akin to insanity, according to one definition? 🤔

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3 minutes ago, Freeforester said:

Time to contact the Russians! Their aftermarket CNC made parts should offer a better fix to this problem, after all, replacing one broken Begode part with another may be described as being akin to insanity, according to one definition? 🤔

I have had enough of this wheel so I will fix it up tip top shape with new part and sell it and be done with it honestly with all the problems I had it's enough. I don't think just looking at material is enough I think the thin parts need to be thicker as well because there are a lot of stress put in place there.

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Please read to the end!!
I strongly suspect that most of this failure is due to the poor stock suspension geometry, which requires that the shock is significantly over inflated for minimal functionality, and thus over torqueing on those parts, causing the observed failure.
 
The shock on the Master is very similar to a MTN Bike's rear suspension. Except where a mountain bike would require maybe a 300lb/in to 500lb/in rated spring, the Master (because of its bad stock linkage geometry) requires closer to 2000lb/in of force!!!
 
I have long speculated that it was just a matter of time where we would start to see the collateral damage from the absurd amounts of force the stock geometry puts on all the supporting components.
 
So, yes, the parts in the photos would benefit from a slightly more robust design. However, the real solution is a simple suspension linkage upgrade.
**While the stock suspension links may apply 1500lb/in to 2500lb/in of force to these components, an upgraded suspension linkage might only apply 300lb/in to 500lb/in!!
Edited by Phi1osopher
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10 minutes ago, Phi1osopher said:
Please read to the end!!
I strongly suspect that most of this failure is due to the poor stock suspension geometry, which requires that the shock is significantly over inflated for minimal functionality, and thus over torqueing on those parts, causing the observed failure.
 
The shock on the Master is very similar to a MTN Bike's rear suspension. Except where a mountain bike would require maybe a 300lb/in to 500lb/in rated spring, the Master (because of its bad stock linkage geometry) requires closer to 2000lb/in of force!!!
 
I have long speculated that it was just a matter of time where we would start to see the collateral damage from the absurd amounts of force the stock geometry puts on all the supporting components.
 
So, yes, the parts in the photos would benefit from a slightly more robust design. However, the real solution is a simple suspension linkage upgrade.
**While the stock suspension links may apply 1500lb/in to 2500lb/in of force to these components, an upgraded suspension linkage might only apply 300lb/in to 500lb/in!!

I replied on facebook also. 😁

I have Kuba linkage on mine with a Rockshox Monarch RT3 at 210 PSI so while you have a point about geometry I changed my geometry from day 1 but I don't think it changes the fact that this part is too weak for the stress it has to handle

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Very sorry / disappointed to hear it of course, and I don't blame you @Rawnei for abandoning the Master. I think I probably would sell it too if I'd had that many problems with mine. But thank you for reporting so the rest of us know what to watch for.

In light of @Phi1osopher's reply though, it becomes more interesting that Begode recently felt the need to release CAD drawings of new suspension linkages - I wonder if these do eliminate or mitigate the stress on that part if CNC'd and fitted instead ? And then, if they do, we gotta find out where we get those made...

But if, as Rawnei says he has had alternative linkages since day 1, then I guess we're all in trouble, and need to be looking for a stronger version of the part that broke on his !

Edited by Cerbera
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11 minutes ago, Cerbera said:

Very sorry / disappointed to hear it of course, and I don't blame you @Rawnei for abandoning the Master. I think I probably would sell it too if I'd had that many problems with mine. But thank you for reporting so the rest of us know what to watch for.

In light of @Phi1osopher's reply though, it becomes more interesting that Begode recently felt the need to released CAD drawings of new suspension lankages - I wonder if these do eliminate or mitigate the stress on that part if CNC'd and fitted instead ? And then, if they do, we gotta find out where we get those made...

As I wrote just above your post I changed my geometry before even the first ride by installing Kuba/Torque Pads linkage with a rockshox shock so unfortunately changing the geometry didn't help in my case.

Edited by Rawnei
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Do EUC manufacturers actually employ an engineer(s) when designing wheels?

Would this weakness have been identified by a qualified engineer, in the design stage?

How much faith/trust would there be, in a new revised Begode replacement/new part?

 

Just look at how close to the edge those holes are drilled......

 

Begode quality.......

 

 

Edited by Paul A
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3 minutes ago, Paul A said:

Do EUC manufacturers actually employ an engineer(s) when designing wheels?

Would this weakness have been identified by a qualified engineer, in the design stage?

How much faith/trust would there be, in a new revised Begode replacement/new part?

Just look at how close to the edge those holes are drilled......

Begode quality.......

I think it doesn't even take an engineer to spot those weaknesses, initial reaction from people designing it should be "ok we clearly need to make this section thicker" then maybe an engineer could chime in how thick it actually needs to be

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1 hour ago, Paul A said:

Just look at how close to the edge those holes are drilled......

Yeah it baffles me that anyone could think that was fine...

AND it looks like it's made of what my mate used to call 'Chinese Bastard metal'; that really low quality grainy stuff that cracks when looked at wrong... sigh.

I'm glad I haven't been doing huge step runs and bump-ups on mine. Looks like I won't be doing them anytime soon either !

Edited by Cerbera
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Just need to check. Have you ever crashed it @Rawnei or is this all, as I fear, from regular riding ? And may I also ask how heavy are you, and do you do much seated riding, though don't know if that makes any difference at all, just wondered if it might ?

Edited by Cerbera
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Just now, Cerbera said:

Just need to check. Have you ever crashed it @Rawnei or is this all, as I fear, from regular riding ?

Just regular riding, nothing extreme, barely even rode it since I had so many problems (broken battery pack etc), treated it like a baby.

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Eurgh.... cheers. FFS. Just written to my dealer to a) notify them and b) order that part (hopefully an alternative or fixed part by begode) in advance of mine breaking.

Edited by Cerbera
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51 minutes ago, Paul A said:

Do EUC manufacturers actually employ an engineer(s) when designing wheels?

Would this weakness have been identified by a qualified engineer, in the design stage?

How much faith/trust would there be, in a new revised Begode replacement/new part?

 

Just look at how close to the edge those holes are drilled......

 

Begode quality.......

 

 

It should be noted at this point in time none of the current suspension designs (🤔) are fully tested or have been found to be beyond reproach (I’ve just ordered myself a Sherman S, by the way, but have no illusions as to the shortcomings of its bridge ‘solution’). I consider the S’s setup to be the least worst, that’s all!

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From Facebook just now:

image.thumb.png.2e941779fbb17dd3dc38993491c59839.png

27 minutes ago, Cerbera said:

Eurgh.... cheers. FFS. Just written to my dealer to a) notify them and b) order that part (hopefully an alternative or fixed part by begode) in advance of mine breaking.

Might want to ask them to delay that since Begode will update the part.

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Since I've almost decided to order the Master shortly and am doing some serious research for the first time, the list of upgrades Begode has yet to do is getting longer and longer. 🤮

 

- Aluminum battery case

- Battery holder/lid also made of aluminum

- fixed linkage geometry

- usable front and rear light

- accurate bushings in the sliders

- reinforced upper frame

- rim (if the tire problem is true) 

- reinforced shock bridge 

WTF, It seems no Master in 2023 for me. 

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20 minutes ago, EUC Custom Power-Pads said:

Since I've almost decided to order the Master shortly and am doing some serious research for the first time, the list of upgrades Begode has yet to do is getting longer and longer. 🤮

 

- Aluminum battery case

- Battery holder/lid also made of aluminum

- fixed linkage geometry

- usable front and rear light

- accurate bushings in the sliders

- reinforced upper frame

- rim (if the tire problem is true) 

- reinforced shock bridge 

WTF, It seems no Master in 2023 for me. 

With all the new models coming out one has to wonder how long they will support and update the master, from experience we know that they abandon old models pretty quickly in favor of new models, the one saving grace could be weightclass but who knows how they reason about this.

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Thinking more about how they would improve this part it seems more challenging than one could first expect, this part moves up and down between the battery boxes so there is not a whole lot of real estate there to make it thicker, would have to redesign everything or possibly redesign the battery boxes to create more space in between them, might be more complex task to solve than first expected.

Making it taller is not great either that will eat away at the travel length

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If we delve into the force lines of the structure, an overloading impact on this node can only come from the jamming of the shock absorber. The shock stroke ends before the sliders themselves reach the bottom. If the shock absorber is working normally, such impacts should not occur in the middle of the bridge. Have you measured that the travel of the shock absorber and linkage is at least as long as the sliders!?

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