I have a 2022 hybrid RAV4 – not a Prime - all wheel drive. I am preparing to take a cross-country road trip and was wondering what a good maximum sustained speed might be (some speed limits are 75+ miles an hour). I’m less concerned with fuel efficiency, and more concerned with excessive wear and tear on the vehicle, particularly the powertrain. What would be the maximum speed that you would cruise it at for hours at a time?
Drive any legal speed you want. It won't make any difference.
1,000 miles of wear is a 1,000 miles of wear.
If you are doing highway driving, you are not going to put much wear and tear on the engine and transmission (i.e. 100,000 highway miles is equivalent to 10,000 stop and go city miles). As far as speed goes, 65 mph.
I drive a 2021 RAV4 Hybrid regularly on long drives, at least 4 hours. I easily go 75+ MPH. As long as you spend less time ABOVE the PWR section of the tachometer, and more time in between ECO and PWR (or even between CHG and PWR), you should be fine. Long highway drives are actually better for the engine than city driving (unless you drive like a maniac on the freeway).
Probably about halfway in between ECO and PWR is the sweet spot.