One Piece Body

[Mr Bond]

TLDR: Can I remove the standard truck cab and replace with a composite shell?



Something has always excited me about cab forward designs and the advantages they deliver in visibility, use of space and practicality. I've hit a point in life where it's an ideal time to get off my ******** and build it. Plan is to use an older full size truck chassis (F350+ for example) and build an entire composite body on top, like the Volvo C303 pictured but, a little bigger. This way I can maximise internal space and indulge my passions for flair. But I've never found anything like this so wondering why?

Potential Pitfalls
Safety: Would require a full rollcage and attention to cab penetrations in case of a crash. Not unusual for expedition vehicles and relatively easy to engineer. Would have to pass Provincial inspection (I'm in BC Canada)
Engine Position: May end up with seats over the engine: again normal. Engine access could be a challenge as can't tilt cab (unless I segment the body, but that adds failure points and thermal management challenges)
Maintenance: Full length body would require removal for major work, but if keep weight low enough that a regular vehicle lift can remove it life will be easier.
Steering Wheel Linkage: This may be a big challenge as the path could be convoluted. Enough U joints can solve anything, but would become brutally heavy if not done right.
Weight Distribution: Moving some weight forward will have an obvious impact on suspension needs and steering. The design would have to account for this, with an acceptance that suspension tweaks are likely once built.
Wiring: Could be a killer as would have to extend all dash wiring. EEk.

Thoughts
I've spent two years researching and investigating options, and as above not found any similar designs. Composite panels are incredibly good now, and a box kit could easily be ordered in the right design. Same with the roll cage (if actually needed). What am I missing?

PS Vehicle will be for myself and my service dog (disabled). Travelling North America and designed for rough roads, not off road. Have travelled all my life and this is simply an evolution.

 

[ExpoMike]

Honestly, trying to build a cab forward rig on an existing truck platform is likely going to not be simple or cost effective. Cab forward frames and layouts are designed from the start that way and have specific setups. Biggest challenge is the steering column and linkage relationship. Engine location in the existing frame is also an issue as it likely needs to move back.

To build something similar (still a lot of time and money) might be better to start with a mid '60's cab forward van (get a long wheelbase model) and covert it over to 4WD. I have been eyeing the project of taking a '60's era Chevy van and pulling all of the running gear out of an XJ Jeep Cherokee and transplanting it. Since most of these vans came with an inline 6 engine and leaf springs front and rear, it wouldn't be too hard to convert over. Other option might be a panel van but they are not really true cab forward but do have a very short nose.

Here are some old pics I saved many years back of doing a 4WD cab forward van conversion (sorry pics are small, that is what I copied off another site)

 

[Jacobm]

I agree with Mike, I think you'd be better served by a standard 4WD van than by custom building something, considering the end result and the expense. Vans are proven and have plenty of factory, aftermarket, and community support, while a custom one-off would have none of those things. If you needed servicing on the road many mechanics may simply refuse to work on it, both due to unfamiliarity with whatever customizations you make and the difficulty in troubleshooting, as well as liability for replacing any one-of-one items they may accidentally break.

Another option that's closer to what you're looking for would be a modified Low Cab Forward truck, similar to an Earthcruiser offering. No doubt you could build one of those and avoid many of the pitfalls you listed while retaining the space efficiency and visibility you're after. Some are offered in 4WD but I imagine it wouldn't be too hard to modify one, especially the Chevrolet/Isuzus which use small blocks shared with their pickup lines. I know some were offered with 4WD stock, and up in Canada it wouldn't be too difficult to import one from Australia if you're okay with right hand drive, since they'd likely have more selection to choose from. Most of them can fit in a shipping container. Since these trucks were designed with tilt cabs and custom bodies in mind, I'd say they'd be a much better platform for a custom rig than stripping the body off a pickup truck. Hell, even full size vans often have cutaway chassis options (think Uhaul trucks and ambulances) so building a composite box on one of those would be easier. With proper mounting you could probably do a walk/crawl through to the body without the headache of figuring out most of the actual drivability aspects of it.

Additionally, I'd be cautious about a roll cage if you're considering using it for frontal protection. The rigidity offered is good for maintaining survivable cab space, especially in a rollover, but that same rigidity means any shock loads are transferred directly to you when hitting something solid like a tree or an oncoming vehicle. Modern cars are safer because they crumple up and absorb that energy before the shockwave reaches your body. If you must have a cage, have a proper harness, one piece seat, and most importantly a HANS device to avoid an internal decapitation like Ayrton Senna or Dale Earnhardt if you're expecting it to take a hit from the front. That being said, most of us aren't riding around in the ideal safe vehicle, so your level of risk acceptance is up to you, but a roll cage is just as likely to cause injury in some accidents as it is to prevent injury in others. Something to consider.

 

[llamalander]

Are those Volvo C303's available in Canada? Can you use that with a new body you build yourself?