pivoting frames and mounting campers

[Zuber]

What do they recommend instead? Is this a Hino chassis? I think this is some sort of pivoting system...?

Having the pivot at the front and fixed points at the rear just looks wrong. It makes the box pivot and flop around way more than necessary. It also puts all the stress at one end of the frame. The front axle has no contribution stabilizing the box.

It seems much better to have the fixed points closer to half way between the axles, like mid way in the chassis. Then the side-to-side box movement is averaged out between the movement of the axles. The result, in that video , the box would almost remain level through the moguls.

 

[Andy Hino]

What do they recommend instead? Is this a Hino chassis? I think this is some sort of pivoting system...?

Thats a MAN chassis I believe
SLRV simply dont want to build anymore vehicles based on the Hino 817 4x4. They built one, and thats it.
They continue to build based on the Isuzu NPS75/155 because it doesn't have electronic stability control, so if the box "flops around", at least engine power won't be cut.
Having said that, the Isuzu does not have anywhere near that kind of chassis articulation , so it isn't really an issue anyway.

IDK, I think half the issue is where they place storage in the bodies. They seem to have an awful lot of overhead cupboards which means if incorrectly loaded by the client, could result in a lot of weight up high.
Not the biggest deal with a bigger truck, but with a smaller truck and with the extra height of the Hino over the Isuzu, it seems to have made enough of a difference that the three point pivot doesn't work.

Its the reason Im specifically designing my habitat with zero over head storage. I figure if I cant carry everything under the bed, dinette and in the kitchen cupboards, chances are Im trying to pack way too much into the truck anyway and I should probably just stay home

 

[Zuber]

I have an Earth Cruiser EXP (pop top). It has a very low center of gravity. No sway bars in the suspension, only leaf springs and it still corners very flat. The box is fixed at the front with spring hold downs to the rear. I never notice the box flopping around. It does have some 'frame slap' on higher speed rough roads.

 

[rruff]

I have an Earth Cruiser EXP (pop top). It has a very low center of gravity. No sway bars in the suspension, only leaf springs and it still corners very flat. The box is fixed at the front with spring hold downs to the rear. I never notice the box flopping around. It does have some 'frame slap' on higher speed rough roads.

I'm curious if this is different than what they have on the new Core? Post #590 has a video that shows it. They have poly bushings at 6 points, and the rear four have springs in addition.

 

[Zuber]

I'm curious if this is different than what they have on the new Core? Post #590 has a video that shows it. They have poly bushings at 6 points, and the rear four have springs in addition.

I don't think this mount has changed.

 

[rruff]

I don't think this mount has changed.

That's great to know...

 

[simple]

Watching the video it appears that having the pivot behind the cab allows the sway/torque (if there is such a thing) from the box to be translated more to rear wheels versus the front. Could it allow for more even articulation of the front and rear axles resulting in better traction by keeping the front wheels from lifting? It was pretty impressive that it wasn't picking front tire.

 

[Ramdough]

The reason that the rear is usually the fixed point is that the truck frame has higher stresses between the axles. By making the fixed point behind the rear axle, the stresses from the box are added to the low stress region of the truck frame and not to the already higher stress area. Also, if you fix near the rear axles, the amount of tire clearance you need is less. Otherwise you have to accommodate the chassis twist and tire lift in your clearance. All of this is more of a problem with a more flexible and/or less strong frame.


In my case, I opted for a front fixed location because it makes my crawl through have less movement and I am not worried about the two issues above (my application has a really strong and somewhat stiff frame).


Sent from my iPhone using Tapatalk

 

[nnamssorxela]

Not much, but I went and put the truck under a little twist just to get an idea. Sounds like I need to do this again when I don't have a bed, and I can get the wheels a little higher off the ground, but there was less twist than expected.

 

[rruff]

You need to be teetering on two wheels to get a good idea. The truck bed doesn't provide much stiffness actually.

 

[Alloy]

Good points. I was told that the 800 lb load/per was static.

The problem of threads cutting the PU could be solved with bolts that only have that last bit threaded.

Sleeve or no sleeve, I don't see a difference in the ability to lean or tilt. They should do that either way... in fact I'm banking on it since I want the rear ones to tilt without too much resistance. But I don't think leaning over while braking is much of an issue since it will be a small movement, and it will spring back as soon as the deceleration is over.

If you can get a wrench in there, it shouldn't be a problem to remove the bolt out the bottom.

If you are interested in the Earthcruiser Core, the guy who made the video above has many on his youtube channel and also has a thread on ExPo.

Using longer bolts and trimming the length to suite would work. Shoulder washers help to. I've had urethane blocks crack where the threads of a bolt cut into them.

The sleeve stabilizes the fixed (no spring) mounts.

Make a big difference on a stuck bolt if the box end of a wrench can be used vs. the open end. Not nessary but something that might make thing easier.

 

[Alloy]

View attachment 715065

Weak link in the chain here is the connection between the post and the longitudinal runners. Gussets will help allot


Might even consider getting rid of the longitudinal runners and placing the crossmembers over the mounts or cutting the longitudial runners into pices and putting them between the crossmemebers.

 

[nnamssorxela]

Might even consider getting rid of the longitudinal runners and placing the crossmembers over the mounts or cutting the longitudial runners into pices and putting them between the crossmemebers.

The reason I have them stacked like that is because I need some height to get the cab over portion of my camper above the cab of the truck. Seems to be the way most of the commercially built flatbeds are manufactured as well. The 3D image I made was just a "proof of concept" and doesn't contain exact dimensions. I was planning on having the crossbars over the mounts. The mounts are not evenly spaced either, in order to be in front of and behind the axle/tires.

Do you suggest cutting the longitudinal runners just to make the frame lower?

EDIT: I only need 5.6" of clearance above the top of my tire with stock tires, but should I ever want to go to 35" tires, I'll need something closer to 7.5" of clearance. Of course a lift would be required to fit those tires, and would add some wiggle room.

 

[Alloy]

The reason I have them stacked like that is because I need some height to get the cab over portion of my camper above the cab of the truck. Seems to be the way most of the commercially built flatbeds are manufactured as well. The 3D image I made was just a "proof of concept" and doesn't contain exact dimensions. I was planning on having the crossbars over the mounts. The mounts are not evenly spaced either, in order to be in front of and behind the axle/tires.

Do you suggest cutting the longitudinal runners just to make the frame lower?

EDIT: I only need 5.6" of clearance above the top of my tire with stock tires, but should I ever want to go to 35" tires, I'll need something closer to 7.5" of clearance. Of course a lift would be required to fit those tires, and would add some wiggle room.

Yes cutting to make the fame lower or it could be done to allow more storage room along the sides

An option to placing the longitudinal runners between the crossmembers is to use a deeper longitudinal section that is notched around the cross members. This increases the welded connections and would balance weld distotion if only welded top (no vertical welds) and bottom. The issues with doing this is the areas that are not welded still need to be sealed. Ideally if the frame is steel it would be galvanized.

 

[Zuber]

Yes cutting to make the fame lower or it could be done to allow more storage room along the sides

An option to placing the longitudinal runners between the crossmembers is to use a deeper longitudinal section that is notched around the cross members. This increases the welded connections and would balance weld distotion if only welded top (no vertical welds) and bottom. The issues with doing this is the areas that are not welded still need to be sealed. Ideally if the frame is steel it would be galvanized.

I don't think notching any 'beam' would be a good thing. It's always best to keep the top and bottom cord undisturbed. Also, it's never good to weld across the cord, along the cord is fine. Any change in the thickness of the cord is a stress riser and will start cracks and break. The longitudinal runners are the primary beam and carry all the load. It's better to leave them undisturbed as possible.