Michelin Energy Saver A/S PSI for Prius v ??

good questions. i can only say that my energy savers purchased a few months ago are listed at 44 max, but they are 15". i have mine at 42/40, in hopes of better mileage, but realistically, can't observe a difference between that and recommended.
i have never seen any scientific testing to back up the claims, but a lot of people will say they have seen a few gallon difference.

 

I run 38 psi, a compromise between comfort and mileage. mpg difference is about 2 mpg. Driving style, distance and temp. is a bigger factor

 

It is widely believed that Toyota's recommendation maximizes comfort.
While the side wall pressure may well maximize MPG, I urge you to choose based on /tread life/safety/handling.
My theory is that finding the pressure that gives the most even wear, is also the pressure that has the most grip. (I did find more difference in the gen 2 than the v)

On my 2012 v Three, that has been 40/38 with my Energy Saver A/S tires. I put them on at 55,000 miles and am at 107,000 and will make it at least one more winter.

 

Michelin Energy Saver A/S P205/60R16 91V only has a max load of 1356lb @ 51psi. Same as the load rating of the Michelin Energy Saver A/S P215/50R17 91V found on the pkg Five with 44psi spec. We don't get load per psi data for passenger tires in the US so suggest using the %/psi increase method. Not less than Placard of course. Example: For 44 psi tires 32psi = 72%, 36psi = 82%, 40psi = 91%. For 51 psi tires your psi's would be 37psi = 72%, 42psi = 82%, 47psi = 91%. I would consider these the minimum psi increase.

Toyo guide for tire load/psi tables
https://toyo-arhxo0vh6d1oh9i0c.stackpathdns.com/media/2125/application_of_load_inflation_tables_20170203.pdf

 

When there's a higher pressure on the sidewall tires are often designated "XL", for "Extra Load", have stiffer sidewalk, firmer ride. Not sure if that's the case here; you could look up the specs on TireRack.

I would just start with the pressure that's on the drivers door decal (Toyota's psi recommendation), then try a few pounds higher.

 

Differences in MPG relative to PSI will vary according to tire size and tire temperature. You should see the biggest gains at higher temps. Cold tires are bad at any pressure.

 

Assuming you've got 65 profile tires, the difference between 35 and 40 IS pretty subtle. It's the low profile 45's that are more punishing, lol.

 

Although I'm in a Gen 3 liftback, agree with @JimboPalmer that 40/38 is the best of all worlds. After much "testing", or more accurately, "playing around with pressures", I found higher psi does not improve mileage but noticebly decreases ride comfort. This is likely due to deflection with regard to imperfect road surfaces, IMO. Much lower than that trends toward less even tread wear to go along with actually only slightly less mpg. Again strictly IMO, and I never go below ~37/35 on any vehicle.

Energy Saver A/S 195/65/15 at somewhere around ~25k miles. Love these tires and love the X-ice 3's just as much in winter. As a cyclist, I've used their high-end road tires since the mid-80's. Michelin does good work.

Sorry OP, for not directly answering your Q's, just offering general obsevations regarding an area I've spent some time playing around with.

 

Just a reminder. New tires take a few hundred miles to break in. When they are new that can drop the mpg a little bit.