G'day, this is the next video that featured the subframe. However I didn't go into detail about the mounts as I never realised they would be of that great of interest. ruclips.net/video/DU0K38eo2UU/видео.html
what is the purpose of the blue coloured frame running parallel on the chassis frame??? is the blue parallel running frame (not the large boxed lateral blue frame mounted on the longitudinal blue frame for the camper body unit) necessary??? is there a way to install only the boxed blue frame to chassis frame instead of the longitudinal blue frame running parallel on top of the longitudinal chassis frame??? this might save some weight!!! please advise!!!
Hello, it serves two purposes in our build. The first is it spreads the load of the camper along the whole chassis instead of point loading the chassis. The second it it provides an appropriate Hight for the water tanks to fit inside along with tyre and underbody accessory clearance. You could make it lighter no doubt, but fully loaded we are still 1 tonne under our GVM so it's not really an issue for us.
@@ned_and_cazz so, if I'm understanding you correctly ur saying that we can install only the intersecting boxed frame fabricated to size to accommodate the camper unit & discard the longitudinal blue frame that is fitted to the longitudinal chassis frame members!!!
Personally I wouldn't on a small chassis like this as point loading it poses a risk of chassis fatigue. The longitudinal sections spread the load. If you have a larger truck with a stronger chassis you could consider it with a three point pivot system. Just remember what ever way you do it to make sure your mounting system allows for sufficient chassis deflection to protect the camper cell from twisting forces
thank you share this video how weight has been put onto the Isuzu truck? how to keep your weight down on your Isuzu truck as have Isuzu 4x4 crew cab truck built in 2010?
We tip the scales just on 5t. If I were to make mounts again I would do it a bit different. They are holding up fine, but there is definitely room for improvement
Hello, all going well so far. However if I was to build them again I would make them slightly different. I would make them as a 'V' shape to promote self alignment. That said, I've had no issues with alignment so far
@@ned_and_cazz Thanks for the reply, I have recently noticed more people are using a kinda central pivot, but use of more than one is probably no better. I also heard of a 3 point method, which sounds like the best idea so far but I have not seen one. Plus a very long box may need more support in the middle. I am looking at a 14-15 foot box, no idea how I will end up mounting it.
@@VEHICROS the three point design is a great design, however in my research I found it was suited to trucks with larger & stronger chassis. I'm not sure the little chassis on our NPS would handle the point loading that it creates. This is why I went for this design to allow the weight to be destributed across the hole length of the chassis. If I had a larger truck I would definitely go a 3 point design
Hi Tony. The springs were sourced from a similar application from a off-road water tanker setup. I have since tested them on the truck and at this stage appear to be performing well.
Frame twist is a factor of weight carried. I would expect a water tanker to have far more weight and frame twist and also for the tank structure to be more rigid/resistant to twist than a habitat, so I don’t think the same springs would be appropriate for a lighter/less rigid habitat… One way to determine spring rate would be to install the base/floor, and add weight to it to equal the all up weight of the habitat when complete and fully loaded. Then lift one rear wheel or back it up onto something until the other wheel just starts to lift off(max frame twist under the hab). Then at the spring side location that is now farthest above the frame due to twist measure the gap. That is the spring compression range you need to meet/exceed. You now need to apply compression force between the hab floor and frame at that spring point until you reach the maximum amount of deflection/twist you want delivered to the floor from the frame at that point. I am thinking this can be done with a hydraulic cylinder with a gauge and hand pump, or perhaps even a large C clamp with a load cell. You compress it till you reach as much twist as you want to impart to the habitat floor. That force applied will be the maximum spring force you want to apply at that point when the frame is fully twisted/spring is fully compressed. You want a spring that can be slightly pre-loaded when setting level and not quite reach full compression at full frame twist for the max weight when things are twisted up… i will hopefully be working on determining just this about spring time:) your mounts look great!
The front of the chassis is where there is more chassis twist and deflection. I can't see this affecting a pass through if you use a accordion style rubber. It doesn't bounce around or anything crazy
here we are I don’t understand. Let’s say I take a double seesaw at a playground to simulate chassis flex. I first make them both horizontal then lift one end up a foot. I now have a vertical difference of a foot at both ends. In the middle there is very little difference in height. Both ends have maximum difference and the middle point has the least. On a truck the front part of the camper section is in between the ends (the axels) so it would have less vertical difference than either end. That’s how I see it, am I missing something?
The difference is a seesaw has one pivot point. The chassis doesn't have a central loading point. It's forced by the resistance of the suspension at both ends. Best way to see it is to take your truck out and flex it up and measure the chassis deflection to get a better understanding of it
here we are I don’t have a truck yet, so I’m still trying to get my head around all this. And I’m still trying to decide between something like yours or a 3 point pivot system. I can see how it could be more deflection at the front seeing as the front is actually very close to the front axel and not in the middle. And I’m guessing the rear end is stiffer than the front end. I have another question, what are the legalities when it comes to building your own subframe. Does it have to be engineer approved, can that happen after it’s built. And do they care if the welder is qualified? Thanks for your replies, I really appreciate it.
Best to consult the engineer that your going to use. I found a few different engineers had different requests and requirements. I looked into 3 point pivot but found that it was not recommended for our thin chassis. It's to high of point loading for it. But works great on thicker chassis
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Which video show part 2 of the subframe springs? Cheers
G'day, this is the next video that featured the subframe. However I didn't go into detail about the mounts as I never realised they would be of that great of interest.
ruclips.net/video/DU0K38eo2UU/видео.html
what is the purpose of the blue coloured frame running parallel on the chassis frame??? is the blue parallel running frame (not the large boxed lateral blue frame mounted on the longitudinal blue frame for the camper body unit) necessary??? is there a way to install only the boxed blue frame to chassis frame instead of the longitudinal blue frame running parallel on top of the longitudinal chassis frame??? this might save some weight!!! please advise!!!
Hello, it serves two purposes in our build. The first is it spreads the load of the camper along the whole chassis instead of point loading the chassis. The second it it provides an appropriate Hight for the water tanks to fit inside along with tyre and underbody accessory clearance.
You could make it lighter no doubt, but fully loaded we are still 1 tonne under our GVM so it's not really an issue for us.
@@ned_and_cazz so, if I'm understanding you correctly ur saying that we can install only the intersecting boxed frame fabricated to size to accommodate the camper unit & discard the longitudinal blue frame that is fitted to the longitudinal chassis frame members!!!
Personally I wouldn't on a small chassis like this as point loading it poses a risk of chassis fatigue. The longitudinal sections spread the load.
If you have a larger truck with a stronger chassis you could consider it with a three point pivot system.
Just remember what ever way you do it to make sure your mounting system allows for sufficient chassis deflection to protect the camper cell from twisting forces
thank you share this video
how weight has been put onto the Isuzu truck?
how to keep your weight down on your Isuzu truck as have Isuzu 4x4 crew cab truck built in 2010?
We tip the scales just on 5t.
If I were to make mounts again I would do it a bit different. They are holding up fine, but there is definitely room for improvement
How are your spring mounts working out, I was thinking of doing something similar.
Hello, all going well so far.
However if I was to build them again I would make them slightly different.
I would make them as a 'V' shape to promote self alignment.
That said, I've had no issues with alignment so far
@@ned_and_cazz Thanks for the reply, I have recently noticed more people are using a kinda central pivot, but use of more than one is probably no better. I also heard of a 3 point method, which sounds like the best idea so far but I have not seen one. Plus a very long box may need more support in the middle. I am looking at a 14-15 foot box, no idea how I will end up mounting it.
@@VEHICROS the three point design is a great design, however in my research I found it was suited to trucks with larger & stronger chassis.
I'm not sure the little chassis on our NPS would handle the point loading that it creates.
This is why I went for this design to allow the weight to be destributed across the hole length of the chassis.
If I had a larger truck I would definitely go a 3 point design
How did you work out your spring rate for the mounts?
Hi Tony. The springs were sourced from a similar application from a off-road water tanker setup. I have since tested them on the truck and at this stage appear to be performing well.
Frame twist is a factor of weight carried. I would expect a water tanker to have far more weight and frame twist and also for the tank structure to be more rigid/resistant to twist than a habitat, so I don’t think the same springs would be appropriate for a lighter/less rigid habitat…
One way to determine spring rate would be to install the base/floor, and add weight to it to equal the all up weight of the habitat when complete and fully loaded. Then lift one rear wheel or back it up onto something until the other wheel just starts to lift off(max frame twist under the hab). Then at the spring side location that is now farthest above the frame due to twist measure the gap. That is the spring compression range you need to meet/exceed.
You now need to apply compression force between the hab floor and frame at that spring point until you reach the maximum amount of deflection/twist you want delivered to the floor from the frame at that point. I am thinking this can be done with a hydraulic cylinder with a gauge and hand pump, or perhaps even a large C clamp with a load cell. You compress it till you reach as much twist as you want to impart to the habitat floor. That force applied will be the maximum spring force you want to apply at that point when the frame is fully twisted/spring is fully compressed. You want a spring that can be slightly pre-loaded when setting level and not quite reach full compression at full frame twist for the max weight when things are twisted up… i will hopefully be working on determining just this about spring time:) your mounts look great!
Two years in and it's working fine.
The water tanks they were from were only 1000ltr units. Cheers for your detailed reply
Is it possible to fix it to the front instead of the rear, to make it more practical for a pass through?
The front of the chassis is where there is more chassis twist and deflection. I can't see this affecting a pass through if you use a accordion style rubber.
It doesn't bounce around or anything crazy
here we are
I don’t understand.
Let’s say I take a double seesaw at a playground to simulate chassis flex.
I first make them both horizontal then lift one end up a foot. I now have a vertical difference of a foot at both ends. In the middle there is very little difference in height.
Both ends have maximum difference and the middle point has the least.
On a truck the front part of the camper section is in between the ends (the axels) so it would have less vertical difference than either end.
That’s how I see it, am I missing something?
The difference is a seesaw has one pivot point. The chassis doesn't have a central loading point. It's forced by the resistance of the suspension at both ends.
Best way to see it is to take your truck out and flex it up and measure the chassis deflection to get a better understanding of it
here we are
I don’t have a truck yet, so I’m still trying to get my head around all this. And I’m still trying to decide between something like yours or a 3 point pivot system.
I can see how it could be more deflection at the front seeing as the front is actually very close to the front axel and not in the middle. And I’m guessing the rear end is stiffer than the front end.
I have another question, what are the legalities when it comes to building your own subframe. Does it have to be engineer approved, can that happen after it’s built. And do they care if the welder is qualified?
Thanks for your replies, I really appreciate it.
Best to consult the engineer that your going to use. I found a few different engineers had different requests and requirements.
I looked into 3 point pivot but found that it was not recommended for our thin chassis. It's to high of point loading for it. But works great on thicker chassis
How much chassis deflection are you allowing for?
At the front edge of the subframe above the chassy it will allow up to 100mm
@@ned_and_cazz How did you work out your spring rate for the mounts?