Tires

In the US, the driver door jamb (left side of vehicle) sticker says 35fromt/33rear PSI for the 185/65 R15.
Many on PriusChat seem to be using 40front/38rear PSI or 38front/36rear PSI.

Your are using 195/65R15, which I think is the Touring size tire. I dont know if the Touring model Prius uses a different pressure or same pressure.

Whatever pressure you use, measure the tire pressure when cold and do not add air exceeding the maxmum pressure written on the tire sidewall.

 

I had Yokohama C.Drive 2 195/55/R16 tyres in the UK, and although they are not marketed as LRR, I found them to be quite good as far as economy goes. I ran them at 39F/37R but you need to monitor the tyre wear and adjust accordingly.

Please be aware, that tyres, even with the same name, may be different in different markets, therefore YMMV (your milage may vary).

The important thing to do is monitor how the tyre is wearing and adjust the pressure accordingly. The correct pressure is the one in which the tyres wear evenly across the road contact surface.

This chart show different wear patterns (take particular note of the first two columns–Rapid Wear at Shoulders and Rapid Wear at Centre:



hope this helps.

 

I ran around 40 on those when I had them. They have a separate inner tread pattern so anything much over 40psi will interfere with your traction and treadwear.