Re: Tyre Pressure When considering the Prius one of the main considerations was the Euro NCAP safety rating, as having a young family, safety is paramount. Whilst I can understand wanting to get improved consumption, for the life of me I can't believe there is any justification for compromising safety by over-inflating against manufacturer's recommendations for the sake of a few dollars.
what should the PSI be for winter tires? 36/33 is the manufacture recommendation for regular psi in summer. I lowered the psi 1-2 and noticed better traction, but I get terrible mpg in winter not matter what I do. I have heard to increase to 42/40 psi, but not sure about that. Any advice?
The correct tire pressure for the Gen 2 (which yours is) is 35 PSI on the front and 33 PSI on the rear. Cold winters will reduce the fuel economy – on any car – but Prius drivers seem to notice it more. Maybe because you have all that info front and center in the info screens. In addition, you will get worse MPG if your tires are under-inflated, but if you need more traction for getting out of a bind, you can lower the pressures temporarily to accommodate that. After the emergency is over reinflate the tire to the correct pressure(s). Higher tire pressures won't improve your MPG by anything significant but will adversely affect your traction and handling. So, the short story is to use appropriate winter tires and set the pressure at the correct pressure.
Toyota makes a tire pressure recommendation, on a decal in the driver's door. There's no mention of seasonal variations, as far as I know.
