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2007 Proton Jumbuck GLi running Nissan eNV200 Gear
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Discussion Starter · #61 ·
Nice build thread. I have a 15' leaf and sort of think about using it for a conversion with a resolve ev controller. Your info is helpful and entertaining. Thank you
More than welcome mate, hopefully if I get time in the next few days and the weather plays nice, I'll start wiring the loom for the controller
 

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One option I've seen is that being 50x50x5 box, some people are inserting a 40x40x5 box through the centre going full width, and also welding a 50x50x5 box between then, essentially making it a trailing solid axle.

When I have a few hours I could CAD it up, but essentially joining the two arms at the trailing edge.

Why people do this on trailers, I'm not exactly sure, but I've seen it on car trailers, likely because the loads vary and they want a "predictable" system.
If you connect the trailing arms with a beam to make them into one part, the effect depend on the location of the beam.
  1. At the pivot axis, the system is still an independent trailing arm suspension, with the beam twisting as an anti-sway (stabilizer) bar and keeping the arms from changing in toe; my Toyota Sienna has this, but the first generation of VW Golf/Rabbit was the first one that I remember seeing.
  2. At the axle line, the system becomes a beam axle (not independent at all), and trailing arm portions must be able to twist to allow roll; when this is done a track rod is usually added (in cars, but not in heavy truck trailers).
  3. Midway between pivot axis and axle line, the system has a compromise between beam axle and independent geometry; this was the most common rear suspension design on inexpensive front wheel drive vehicles for many years.
In any position, integrating the two trailing arms into one large component requires parts of that component to flex for the wheels to travel different amounts (meaning that the vehicle is leaning), and resistance to that flexing provides roll stiffness. A 50 x 50 mm box is very stiff, and no production car uses something like that near the pivot axis (where it is required to twist); usually they use a C-channel with enough bending stiffness to maintain alignment but not so much torsional stiffness.

Integrating the arms together also means that the resulting arm/axle/beam only needs to pivot on two frame mounts. If the frame mounts are designed appropriately, as lateral force shifts the assembly left or right due to bushing compliance it moves one side forward and the other side rearward to "steer" the whole assembly into the turn for stability.
 

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Yeah that could be an option to me, absolutely, I'm just concerned about restricting the travel of the trailing arm is all, as there is very little room under the car.
I understand why the shock absorbers are tilted, but if you have equal height available ahead of and behind the axle line (as it appears you do), tilting them forward instead of rearward still allows the same travel and provides better geometry.
 

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2007 Proton Jumbuck GLi running Nissan eNV200 Gear
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Discussion Starter · #65 ·
I understand why the shock absorbers are tilted, but if you have equal height available ahead of and behind the axle line (as it appears you do), tilting them forward instead of rearward still allows the same travel and provides better geometry.
Interesting, as the manufacturer shows these always going rearwards.

 

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Interesting, as the manufacturer shows these always going rearwards.

Yes, the Australian trailer suspensions routinely have that shock mounting. That doesn't make it right, it just means that nothing has forced them to improve it. Given that they're competing (in the trailer market) with leaf-sprung beam axles and with rubber-sprung trailing arm suspensions with about 75 mm of total travel and no shocks, by just having long independent arms they still come out on top.

If you look at the image that Cruisemaster uses for the web page for the XT, you can see that tilting the shocks forward would interfere with the springs and structural bracing... and there we see why they put them rearward.
 

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Discussion Starter · #67 ·
Yes, the Australian trailer suspensions routinely have that shock mounting. That doesn't make it right, it just means that nothing has forced them to improve it. Given that they're competing (in the trailer market) with leaf-sprung beam axles and with rubber-sprung trailing arm suspensions with about 75 mm of total travel and no shocks, by just having long independent arms they still come out on top.

If you look at the image that Cruisemaster uses for the web page for the XT, you can see that tilting the shocks forward would interfere with the springs and structural bracing... and there we see why they put them rearward.
Yeah so I'll still have that issue sadly, as there's not a great deal of room under there.

Maybe I'll be better off tossing the stock ones in the bin and going a decent remote reservoir model like the Amada Extreme or something?


I suppose once I've got it ticked off, I can do what I want with it to improve it, as long as I don't "fundamentally change the design"
 

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Yeah so I'll still have that issue sadly, as there's not a great deal of room under there.
Unlike the Cruisemaster XT example, you will have coil springs instead of much wider air springs, so if you mount the shocks inboard enough they could lean forward pass by the springs.

Another alternative would be to mount the shocks ahead of the springs and axle line, with the lower end of the shock extending down through the opening in the arm.

The off-road trailer suspensions typically have the lower shock mounts on the arm at axle height, and at least the version above with blue control arms does that as well (the spindle location is not clear in the latest version with the red arms). There's no reason for them to be that high: conventional automotive shocks almost always mount much lower than that, because an on-road vehicle doesn't need that much ground clearance for the shocks and doesn't have anywhere close to that for other components anyway. A lower mounting point makes the forward location more reasonable, and would even help with the rearward location.

Maybe I'll be better off tossing the stock ones in the bin and going a decent remote reservoir model like the Amada Extreme or something?
Since the problem (which isn't a big problem anyway) is with the geometry, causing the shock to lose effectiveness as the wheel moves up because the shock doesn't travel as much per unit of wheel movement, changing shock type isn't likely to help much, or to be necessary.
 

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Discussion Starter · #69 ·
Unlike the Cruisemaster XT example, you will have coil springs instead of much wider air springs, so if you mount the shocks inboard enough they could lean forward pass by the springs.


Oh I was going to go with the Cruisemaster XT Coil, it comes in 2 models. Air and Coil.

I did look at modifying the main units they already make, but here the opinion is "Nope, you modified with suspension, now start everything over and do destructive testing on the modified parts!"

So I'd then need to buy 2 kits. Maybe more.
 

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Oh I was going to go with the Cruisemaster XT Coil, it comes in 2 models. Air and Coil.

I did look at modifying the main units they already make, but here the opinion is "Nope, you modified with suspension, now start everything over and do destructive testing on the modified parts!"
Yes, if you're using purchased components rather than building your own, there are consequences to modifications. No physical problem (these are straightforward steel fabrications), but legal consequences and you do need to understand the effects of your changes.
 

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Discussion Starter · #71 ·
Yes, if you're using purchased components rather than building your own, there are consequences to modifications. No physical problem (these are straightforward steel fabrications), but legal consequences and you do need to understand the effects of your changes.
Yeah exactly, and the thing is, now that I'm considering this as a business venture after pressure from people watching my build, and the fact that it might be viable, I'm starting to realise that off the shelf parts are good, custom making things is bad.

I mean I could leave the shocks on that trailing arm and relocate where they go to in order to make them more vertical and avoid some of the travel issues, or switch them out for a different length (if they are too long to do that)

Honestly when I started this project, I wasn't considering this as a business venture, not by a long shot. I had the business name and business under to get me cheaper parts from wholesalers (nice little life hack if your county allows that)

But now, there's been enough interest that it might be viable.

I mean as you say, we could build it and have it handle like absolute crap, so back to the drawing board.

However stock, both me and the engineer are amazed that this was allowed on the road, the single parabolic leaf that was in them was just horrible, way over tensioned, empty they buck like an angry bull, loaded they are so wallowy and unresponsive they like to get up death wobbles.

We're trying to find a nice middle ground, at the end of the day it's a commercial vehicle, not a sports car. And we keep having to remind ourselves that no one is street racing these, they go to the hardware store or to go shopping.

At least that's what I'm using it for, and 99% of people, the very few that are dropping big horsepower 4G63 motors in them generally are rebuilding the rear end differently anyway, and not for load carriage.

I mean, for all I know the FEA could come back and this being an inherently flawed system that shouldn't be on anything, even trailers. Just the rules that allow it on trailers are pretty fast and loose.

But we don't know just yet where that will end up.

But I have an idea and I'm gonna go play in CAD for a minute, stay tuned.
 

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Discussion Starter · #72 ·
Right, so first update in months and this one is painful to say.

I WAS WRONG!

So it is going to be a colossal nightmare where I am to get independent suspension engineered to go in the car, manufacturers won't even talk to my engineer over the FEA for the suspension, not even a report to say "She's good"

So we are resorting back to Leaf Springs! Huzzah! Yay for bumpy rides.

So I need to get the car together enough that I can get the old springs out, build the subframe, get the battery in, and then measure up what springs I need. I have CAD models, but it's a pain in the arse to rust simple CAD modelling.

Further, I don't believe I will be using the Resolve VCU anymore.

I have an entire eNV200 sitting here with a (mostly) intact wiring loom and full suite of computers, and as they say, if it ain't broke...something something.

If I had no car, then yeah, the resolve would work, but as it stands, I have all the wires I need, a full modern dash, airbags (Which I may yet disable, or at the very least relocated to a common area that I wouldn't mind being exploded in a crash), and all I really need to do is trim 10mm off the dash either side, lose the inverter under the dash, and....well that's about it besides extending some wires between 30-100mm...
 
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Although swapping in a different suspension appears to have been ruled out, in the time since the suspension design was being discussed the Ford E-Transit has been shown in more detail... and it has a properly designed semi-trailing arm independent rear suspension that mounts under a van floor structure. It is also driven, but that doesn't matter - it would work fine without the axle shafts.
Ford releases e-Transit details
Of course given the relative sizes of the Transit and NV200, the actual E-Transit suspension would probably be too large (too tall, too wide) for the Nissan.
 

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Discussion Starter · #74 ·
Although swapping in a different suspension appears to have been ruled out, in the time since the suspension design was being discussed the Ford E-Transit has been shown in more detail... and it has a properly designed semi-trailing arm independent rear suspension that mounts under a van floor structure. It is also driven, but that doesn't matter - it would work fine without the axle shafts.
Ford releases e-Transit details
Of course given the relative sizes of the Transit and NV200, the actual E-Transit suspension would probably be too large (too tall, too wide) for the Nissan.
I suppose good it's not going in the Nissan.

But at this point, I don't mind, it gets the ute on the road quicker, and that's all I care about.
 
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