What am I safe to inflate the tires up to? 40? 45?
Right. We used to say that overinflating led to excessive wear in the center of the tire but with belted radials this is not a problem. I got about a 5% increase in mileage in my last car by increasing the inflation to half-way between the recommended inflation and the sidewall maximum.Overinflating tires slightly generally improves wear but is not recommended in snow or on rough roads.
Due to the weight of the volt, however you can easily go to 50psi and hardly notice.
Range is much higher at 50psi.
However, no matter what, you can always inflate to the sidewall rating (when the tire Is cold)
The rating is there for a reason afterall.
... but only with the stock tire. If you replace the tire, you need to take into account the max sidewall pressure as well.The door sill rating is provided by the manufacturer as the best combination of performance, comfort and efficiency in all conditions from blazing hot to frigid cold, dry, rain, snow, ice.
Um no, that isn't universally true, my volt with 50psi (ish) in the tires corners much better on clean dry pavement than it did with slushy 32psi (or whatever the dealer decided to toss in there), feels like the car was falling over with 32psi.High PSI is a safety concern, you are shortening the contact patch making the car less directionally stable, and making the contact smaller, which increases stopping distance.