What is the optimal RPM for cruising speeds? When do you shift?

Before it redlines
When it redlines

>>28506468 (OP)
I drive an automatic. The whole setup runs at about 1800 going 70, 2300 at 85, about 2800 at 100.

>>28506468 (OP)
>What is the optimal RPM for cruising speeds?
As low as you can without lugging the engine
>When do you shift?
Depends how hard I’m accelerating. Normal short-shift at about 4k; for hard acceleration then redline at 7.2k

depends if highway or twisty back road but generally 2-3000 rpm
my engine is pretty gutless below 3000 rpm and it won't accelerate much if you need to do an urgent maneuver and its in manual-mode in too high a gear

i have it in smart mode and it tends to give me lots of revs but weirdly if its a downhill curve and its not in manual mode it gives me way too high a gear usually
i just dont get how it cant have a yaw sensor and downshift if it senses too high a g force

>>28506468 (OP)
On my 4 cyl i stay under 3k revs

i shift when the shift lights turn red

no idea
motor tells me when to shift

>>28506468 (OP)
my last car, had a really high final drive, 4.7:1 and i could shift low and the motor didnt have a problem with 5th gear going 35 imagine 1500rpm. my current car it really needs to be taken to 3000 to shift. the ratios and the speed limits all have the car cruising around 2500 i feel like under 2000 is lugging the motor

>>28506468 (OP)
I think highest speed with lowest rpm (highest gear) possible without going lower than 1500 rpm something because it then considers it idle and starts burning more gas

I use my ears