Spare tire- with or without jack?

[crashmtb]

While the idea of lifting the truck to max height then retracting a damaged wheel/tire for repair is appealing, it likely won't work. The air suspensions I'm familiar with are all single acting meaning that pressure is only applied to one side of the piston/bag to extend the cylinder, retraction is via gravity and the weight of the vehicle. To make the jacking solution work, they'd need to be able to pressurize both sides of the piston/bag, which is more complicated, but not out of the question.

as far as I am aware the rivian suspension is hydro pneumatic, like Citroen, or more recently Mercedes ABC. Allows control over each wheel.

There are airbag jacks for the offroad community, I had one for my Xterra. They typically inflate from vehicle exhaust, but that obviously won't work with the Rivian. One with the ability to connect to an air hose seems feasible. The major downside would be time to inflate (they are large volume) and that they take up a lot more storage space than a manual jack.

Not like the giant balloon-like exhaust gas filled ones.

This kind:

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[Autolycus]

The idea of having the punctured tire just lift itself off the ground is wonderful, until you also start thinking about how gravity interacts with things. I think it would be a major safety hazard to have nothing supporting the 4th corner of the vehicle. It just takes one experience with a four-legged table or chair which isn't on a perfectly level floor to understand what I mean. Triangles are perfectly stable... as long as the center of gravity of the object resting on the triable is solidly inside the triangle.

 

[cohall]

The idea of having the punctured tire just lift itself off the ground is wonderful, until you also start thinking about how gravity interacts with things. I think it would be a major safety hazard to have nothing supporting the 4th corner of the vehicle. It just takes one experience with a four-legged table or chair which isn't on a perfectly level floor to understand what I mean. Triangles are perfectly stable... as long as the center of gravity of the object resting on the triable is solidly inside the triangle.

I'm no engineer, but I feel like the solution to that would be to have a sensor that knows when the "4th" corner is sufficiently supported by a jack or block. Then, and only then, lift up the offending wheel for service.

Probably too complicated and cost prohibitive, but it would be cool.

 

[CommodoreAmiga]

I'm no engineer, but I feel like the solution to that would be to have a sensor that knows when the "4th" corner is sufficiently supported by a jack or block. Then, and only then, lift up the offending wheel for service.

Probably too complicated and cost prohibitive, but it would be cool.

But things shift. What happens if the wind changes, ground moves, or someone hops in the bed of the truck while it’s balancing?

I recall watching a documentary that included an old vehicle (think it was a ’50s GM) that had a built-in hydraulic jack. You could open the side skirt (vehicle had those too) and flip a switch and a hyraudic bottle jack that was built-in behind the skirt would extend and jack the vehicle up. Kinda cool.

 

[cohall]

But things shift. What happens if the wind changes, ground moves, or someone hops in the bed of the truck while it’s balancing?

Right, but wouldn't 4 points of contact like I described be essentially no different than jacking up one corner and removing the wheel? Jacks can, and do, slip out all the time.

Just an idea. Maybe I'll go file a patent and sell it to someone.

 

[SoCal Rob]

Pneumatic would be nice, but having a manual mechanical jack is still a must, imo, as the onboard air could fail.

This is my concern, too. If we’re off-road and without mobile phone coverage, I don’t want a compressor issue to leave me stranded. Our Land Rover has a notoriously-bad scissor jack so I keep a bottle jack in our off-road kit.

if Rivian had a jack which could be used to raise the vehicle manually or as a stand when used in conjunction with the height-adjustable suspension then I’d be fine with that.

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