achuch3 - excellent post, thank you! As you point out, 4WD is needed when driving down the mountain on steep slopes, it's not required for driving a car to the summit region. As for using 4WD on paved surfaces, I think I'll leave that to others more expert in the field. As observatory staff, we are not allowed to use 4WD on the paved road (unless they are icy or snow-covered) and think it's due to the hubs being locked and the turning ability being compromised. However, this comes from decades ago when we drove Broncos to the summit and had to actually get out of the vehicle and lock/unlock the hubs when switching between 2WD and 4WD. I don't know if locked hubs are still an issue with modern 4WD cars.
When driving down below the VIS, I use the brake-stabbing technique dobanian mentioned earlier in the thread, but that requires you to have used 4WD low on the dirt road above the VIS to avoid having hot brakes beforehand.
When driving down below the VIS, I use the brake-stabbing technique dobanian mentioned earlier in the thread, but that requires you to have used 4WD low on the dirt road above the VIS to avoid having hot brakes beforehand.