Hi, The Niro EV manual states "Snow tires should carry 28 kPa (4 psi) more air pressure than the pressure recommended for the standard tires on the tire label on the driver's side of the center pillar, or up to the maximum pressure shown on the tire sidewall, which-ever is less." I am thinking that this is related more to efficiency than it is to traction. And I care more about traction than efficiency on my daily drives, so I have not added the extra 4 PSI to the winter tires. On a long winter trip with good road conditions I might consider adding air to the tires. Does this make sense or should I increase the tire pressures as recommended? Thanks!
I chose comfort and lowered my tire pressure to 33 PSI to soften the ride. Efficiency didn't take much of a hit, surprisingly. As for hydroplaning, the tires themselves do a great job. Where I live, I don't get much snow so I can't speak about that aspect.
Remember that as the temperature drops the air pressure inside the tires will drop as well. Nissan suggests 36psi for the Leaf. This will drop to under 30 in really cold temps and sometimes enough that the low pressure warning comes on. I top up with a bicycle pump as things get colder.