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Sherman-S 3600wh: 100V, 20", suspension, 97lb


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18 hours ago, Unicycle Santa said:

however this does not change anything as that entire unit (upper suspension and battery case) can just be considered one unit that is connected via 4 bolts to the top section of the wheel. 

Just been getting up to speed with Sherman S updates and saw this along with a couple of other comments about the same thing. I haven't actually seen how the top of the legs are attached, do we have any pics/vids showing the area yet?

Tbf the legs are so short they may well 'get away' without the cross brace that is used just above the tyre on MTB forks, but yes they deffo need to be securely and strongly attached at the top. Both would be even better though...

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19 hours ago, Unicycle Santa said:

This is exactly what I have been trying to convey, and what we have been discussing in the eevees telegram chat. However it seems many people are unable to visualize the physics behind what's going on to understand why the current setup is an issue. They argue that the suspension is joined by the axle, but that's only half the equation. The two upper units are independent and will be subject to differing forces due to one being rebound and the other being compression, ultimately transmitting a twisting force through the upper section of the wheel where the motherboard is stored. They then argue that the suspension is secured to the battery cases, however this does not change anything as that entire unit (upper suspension and battery case) can just be considered one unit that is connected via 4 bolts to the top section of the wheel. 

So to answer your question, yes. The two upper suspension units should definitely be bridged above the tire/under the motherboard by a solid 1 piece unit such as the one you posted. They even could have made the motherboard and mudguard both mount onto this bridge, making it a very structurally sound wheel. 

Regarding the rest of the wheel, I haven't seen too many other things that stand out as an issue. The wheel only being 100v kinda bothers me for the price being asked, but other than (and the aforementioned suspension design) I think its a pretty solid wheel.

Where is the telegram chat?

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2 hours ago, Planemo said:

 

Tbf the legs are so short they may well 'get away' without the cross brace that is used just above the tyre on MTB forks, but yes they deffo need to be securely and strongly attached at the top. Both would be even better 

 

Inverted mtb forks do not have or need the brace that is mentioned. Most offroad, dualsport, small adventure bikes don't use it either.  

 

 

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7 minutes ago, Jon Wall said:

 

Inverted mtb forks do not have or need the brace that is mentioned. Most offroad, dualsport, small adventure bikes don't use it either.  

??? Even FastAce's own inverted MTB forks have 3 points of crossbrace - axle, lower and upper headstock.

Most other MTB forks use axle, crossbrace above the tyre and lower headstock. So still 3 points.

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1 hour ago, Jon Wall said:

 

Inverted mtb forks do not have or need the brace that is mentioned. Most offroad, dualsport, small adventure bikes don't use it either.  

 

 

Yeah I'm not sure what you are referring to. Every single suspension setup with dual forks has them solidly connected at the bottom and top. Motorcycles have a triple tree that provides two clamping zones, downhill mountain bikes have the same. No inverted (or regular) suspension setup is joined across the top by 3 separate parts held together by 8 bolts, it's always at least one single metal part. 

Edited by Unicycle Santa
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Yes motorcycle forks have 3 points of connection: the axle, the mid clamp, and the top clamp.

The problem isn't that the Sherman-S only has 2 points of connection. These forks are very short, so that's not an issue. The problem is it's upper point of connection is just to the battery box instead of a solid metal bridge to the other fork. Never mind using 2 clamps, there isn't even 1!

By the way, even if each fork was identical inside with even forces, it's still structurally a terrible way to join the forks. It holds it together but not rigidly, and as seen in WrongWay's video, it's going to flex and rattle the screws lose which makes things even worse.

Using even a single clamp towards the top would make it extremely rigid which should be the goal. As stated already, the motherboard compartment can be bolted on top of the clamp, and the mudguard below the clamp. 

 

Edited by InfiniteWheelie
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15 minutes ago, InfiniteWheelie said:

Yes motorcycle forks have 3 points of connection: the axle, the mid clamp, and the top clamp.

The problem isn't that the Sherman-S only has 2 points of connection. These forks are very short, so that's not an issue. The problem is it's upper point of connection is just to the battery box instead of a solid metal bridge to the other fork. Never mind using 2 clamps, there isn't even 1!

By the way, even if each fork was identical inside with even forces, it's still structurally a terrible way to join the forks. It holds it together but not rigidly, and as seen in WrongWay's video, it's going to flex and rattle the screws lose which makes things even worse.

Using even a single clamp towards the top would make it extremely rigid which should be the goal. As stated already, the motherboard compartment can be bolted on top of the clamp, and the mudguard below the clamp. 

 

Yes, I agree.  Veteran will come out with a Firm ware update to fix this.

Seriously, I don't know if this can be fixed. Changing the wheel structural designs at such a late stage. Maybe the Controller box can be made of a stronger material and reinforced. In addition, this is all new territory, a real suspension forks wrapped by batteries.

Edited by DragonFZ
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2 minutes ago, DragonFZ said:

Yes, I agree.  Veteran will come out with a Firm ware update to fix this.

Seriously, I don't know if this can be fixed. Changing the wheel structural designs. Maybe the Controller box can be made of a stronger material and reinforced.

No matter what the issue is that the force balancing both upper suspension units is being transmitted through two separate junctions held together by bolts. There needs to be a solid member underneath. That being said, it's entirely possible no one will ever notice an issue if the strength of the joints is marginally higher than the force being transmitted, but it doesn't change the fact that it's not an optimal design. Lack of failure =/= proper design.

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Consider a non-suspension euc.

It has a pedal hanger, one on each side of the axle. Do the hangers need to be rigidly connected at the top? Why not?

Next, consider a suspended euc, except the suspension is built into each hanger, one on each side. Otherwise, the euc is the same. Only the rider is suspended when standing on the pedals. Do the sprung hangers need to be rigidly connected at the top? Why not?

Does the axle need to be stout? Do the hangers need to be rigidly fastened to the axle? Absolutely in both cases.

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Like Santa and another Rider pointed out, it is the twisting force of having one compression suspension and the other rebound suspension. This is not like the V11 suspension nor non-suspension. There's extra forces (what? up to 84 lbs or more) twisting up while the other want to go down. For MTB, they made it one whole unit by the cross braces.

But then again, this is all speculations. Fastace must have some input on how to make it work

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Keep in mind that when using a metal clamp, it need to be placed high enough on the forks so it doesn't hit the tire when the suspension is compressed. I say this point only to illustrate that it wouldn't be placed just above the tire like that plastic mudguard bridge...

The plastic bridge can be placed so close because it's attached directly to the axle, and therefor moves up and down with the tire. When using a metal clamp you can either continue using the axle-mounted mudguard, or simply place a mudguard under the clamp and let it move up and down in relation to the tire.

You'd then bolt a one-piece metal frame directly on top of the clamp, which acts as the grab bars and a place to attach the lights, seat, trolley handle etc. You'd also bolt on a one-piece metal box directly to the clamp, which houses the controller and charge ports (like the Abrams).

 

Edited by InfiniteWheelie
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28 minutes ago, techyiam said:

Next, consider a suspended euc, except the suspension is built into each hanger, one on each side. Otherwise, the euc is the same. Only the rider is suspended when standing on the pedals. Do the sprung hangers need to be rigidly connected at the top? Why not?

Yes, the sprung hangers need to be rigidly connected at the top, otherwise your feet can independently move up and down on each side! I can't imagine what a nightmare that would be to balance on. Imagine leaning for a turn and your inside pedal dips more than the outside pedal because you shifted your weight. Both sides (pedals) must move in sync with each other.

And if that top connection isn't structurally sound, then those uneven forces (ever-present when riding EUC) will twist and eventually weaken or break the top connection. Which in this case, is the control board box.

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2 hours ago, buffs said:

Thanks!

17 minutes ago, dycus said:

Yes, the sprung hangers need to be rigidly connected at the top, otherwise your feet can independently move up and down on each side! I can't imagine what a nightmare that would be to balance on. Imagine leaning for a turn and your inside pedal dips more than the outside pedal because you shifted your weight. Both sides (pedals) must move in sync with each other.

And if that top connection isn't structurally sound, then those uneven forces (ever-present when riding EUC) will twist and eventually weaken or break the top connection. Which in this case, is the control board box.

No bueno.

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I wish I knew how to use CAD, it would be really fun to design wheels with others on here. Heck, even to show the manufacturers what kind of designs or improvements we want. These are really simple devices so there's not a lot of pieces to model, especially when just trying to convey rough designs and features.

 

Edited by InfiniteWheelie
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Might we be in danger of getting just a little ahead of ourselves here?      Surely the likes of Adam, Bradley and others actually riding and testing the thing might be able to clear this aspect up in the real world,  indeed some like Ian will do 1,000km tests before giving the all clear, and as I mentioned before, I’m sure all manufacturers  wish to avoid a KS S20-type meltdown, I’m guessing that Fastace and Leaperkim have considered this aspect fully also?

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1 hour ago, DragonFZ said:

 There's extra forces (what? up to 84 lbs or more) twisting up while the other want to go down. For MTB, they made it one whole unit by the cross braces.

Thats not how it would work. One doesn't 'want to go up' whilst the other 'wants to go down'. Under compression the non-sprung side will be on it's compression damping so will see resistance just like the sprung side. Not as much, granted, but they are not opposing forces. In any event, the axle interface should tie both stanchions together in terms of vertical action just like any other inverted fork.

My concern is as previously stated - the potential foward/aft flex of both legs not to mention the left-right twisting forces if the legs are not rigidly supported at any point other than the axle. I accept that because they are inverted the upper legs are by default pretty stout, but even so...

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2 hours ago, InfiniteWheelie said:

The problem isn't that the Sherman-S only has 2 points of connection.

Inmo V11 (the first suspension EUC!) has the same need for bracing the left-side slider to the right-side slider. 
They achieved it using a very minimalist cast potmetal top piece. It works; but is vulnerable to crash damage and some riders have broken them accordingly.

IM-V11-TP-MTL-CGE-01-700x700.jpg

Sherm-S' structure using many bolted connections between strong metal components seems study by comparison... time will tell.

 

Edited by RagingGrandpa
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1 hour ago, Tawpie said:

I wonder if the magnesium allow side panels are supposed to help stabilize the top... magnesium allow is rigid to the point of being brittle.

Wouldn’t that depend on the alloy mix?     Istr Jack hammering away at the new S wheel rim, to prove to viewers that it isn’t brittle, unlike the original Sherman rims; I get that it’s not Magnesium, of course, but I feel it serves to illustrate the point.

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1 hour ago, That Guy said:

And now - back to the hype! :-)

I think you got him mixed up with Chooch. 🙂

Granted, there may be some biases here and there, but I thought he explained himself well, provided a solid data point.

Well, on the other hand, the EEVEES review was more like a love fest, minus Lukas's lovefest for the S22. 🙂

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