So, for me, this is a relatively new way of thinking about my Model 3. As an unexpected (and incredibly shocking) birthday gift, my parents decided to upgrade me to a LR battery. Suddenly, there's the potential for me to get out into our highlands - a remote, extensive uninhabited wilderness where the best "roads" are just "someone drives a bulldozer across this route once a year", and the worst are "stakes pounded into a lava field", and where only the largest bodies of water are bridged.
Now, having to deal with rough roads has to some extent always been my plan, as my land is on a (sometimes poor condition) gravel road. But this is a whole new possibility, and it's got me thinking a lot about the details. And I'm sure some other people have also thought some about taking bad roads (or no roads!) in their Model 3, so please join in here!
Protection: I had previously not planned to do anything special to protect the paint. However, if I'm going to be taking highland roads, I really should have a clear bra applied to the "likely strike zones", ideally with a ceramic coat on the whole vehicle as well.
Extra rims: An extra set of "junk" rims should also be on my to-buy list. They can be scratched up and ugly, but ideally lightweight. I could leave offroad tires permanently mounted to them. Will a full set of tires and rims fit in the Model 3 with the rear seats down? I think I've seen that somewhere, but I'm not positive.... The idea would be that I could either A) drive on my normal rims / tires out to the highlands, then swap (and swap back on the far end), and have the original rims / tires as a backup in case of blown tires; or B) swap out at home, and swap back when I get back home - giving me more space inside, and saving some weight (aka extra range), but requiring me to rely on a tire patch kit as a safety measure.
Air suspension: Duh. I don't think I'd make it very far without being able to add at least a bit more height to the car. This of course would put me dependent on Tesla's timing whims... but at the very least I can't order until Eurospec comes out and they decide to start delivering to Iceland, so I have some time
Larger tires: The offroad tires should ideally have about 1" extra rubber on them (since the suspension will be set to "very high" where possible, "high" the rest of the time - giving more room in the wheel wells). I imagine that 1" larger OD is about the most one could add on "high" without risk of bouncing up against the wheel wells?
Clearance: If the air suspension stroke is like with the Model S, then "High" would add 0,9" and "Very High" would add 1,3". Combined with an extra inch of rubber, and the base 5,5" , this corresponds to 7,4" at over 10mph / 14 kph and 7,8" at under 10mph / 14kph. I wouldn't try lava fields or glaciers on that, but the primary potholed / washboard "bulldozer-made" roads? Yeah, I think that's just fine. But what about water crossings?
Water: Wish I had better data for what levels are okay, but we can try to derive them. Clearly, Model 3 must be able to handle driving through "normal" levels of water in a city, because standing water happens, and you can't have gasoline cars happily driving through while Teslas die from a splash. Specifically, it must be able to handle them at low suspension settings, since some people will run in low all the time, so ~4,8". So on "very high", with an extra inch of rubber, this would put the offroad config at handling water "Three inches deeper than the maximum city water accumulation that the car would be tested to"
What about water that's unexpectedly deeper? We've probably all seen Teslas functioning in "boat mode". But we've also probably also seen Teslas that have flooded. I think the best description of the behavior, from what I've seen is "if the car enters water level and low speed, it should float and stay functional for some number of minutes, but might (will?) slowly flood over time" Hitting water at speed, or at an angle (such as sideways), seems to result in a rapid shutoff (at least as far as Model S goes) - but if exposure isn't too long, the car is often recoverable, and sometimes just needs to drain to reboot. Some have even started back up after surprisingly long water exposure times, although this seems to be the exception, not the rule. Again, though, these are limits that I definitely wouldn't want to be pushing up against!
I wish we could have some more detailed data from Tesla quantifying the risks associated with different water levels. With a gasoline car it's easy to quantify: if the air intake gets flooded, you'll flood the engine and the car will die. If it doesn't, you won't, and it won't. But with a Tesla, it feels like so much guesswork.
Any other things that should be considered?