Purchase only 2 tires?

Alignment problem is the first suspicion. Actually you're doing pretty well to get 41K.

I buy two at a time, putting the new ones at the *rear*, moving the old ones to the front, and never rotate them otherwise. It's safer (it reduces the chances of fishtailing) and it saves bother.

 

Since the car is front wheel drive, shouldn't you put the new tires in the front?

 

Technically the best should go in the back but us people in snow country care more about not getting stuck LOL, so the new ones go on the front

 

No. Control is more important than acceleration.

 

Yes correct, but few people try to make a mountain curve at 70 mph, it is better to have the good tires in front.

FWD cars tend to understeer, better traction in front minimizes understeer.

 

Going around corners needs all tires to be good. Control disappears if only the rear tires lock up during hard braking.... I'm not sure if the Prius antilock brakes make it not necessary to put the best tires aft or not.

 

It's easier to recover from understeer. Oversteer is harder. I got to practice both while learning to drive in Wisconsin winters.

 

I go with the front. On fwd, the traction is in the front, but on any car, most braking is in the front, and you need tread to stop on snow and reduce hydroplaning.

 

Weight Distribution, F/R (%): 59/41 for 09 Prius.

More weight on the front, front wheel drive means drive wheels get the best tires , also on braking , additional weight transfer to front.

While tires on the rear would be better in the case of fishtailing, there are a multiple of other road conditions/situations that make the front ones the choice for me.

Sam's club last spring tried to get me to put my two new tires on the rear, it was policy. Of course I didn't listen. Hopefully they've stopped that recommendation by now.

 

I heard about 'snow tires'. Are these the kind with nails in them?
What happens to them when it gets warm again?
Do you leave them on all year?
Do you buy 2 of them or 4?
Are they good rain tires?

Should I put this kind on my car if I drive up north this winter? Where do you get them?
Will the window defroster take ice off? If not, how do you get it off?
How do you get ice and snow off the rest of the car?

How does cold weather affect the batteries?
Do you need special wiper blades for snow weather?
Do you need a special antenna for the radio & satellite?

Will the heater work well enough so that I can leave my coat in the luggage?

 

You can get snow tires with studs in them, but other snows don't. The ones without have different tread patterns to help in snow, but more importantly, they are made from a rubber that stays flexible far colder. There are other features such as an ability to suck a film of water off ice etc that may or may not actually work.

The more agressive tread makes them noisier and the softer rubber mean you probably shouldn't use them year round esp in hot places.

All season tires are probably ok for a visit north, but be prepared to leave more space. The bigger problem is going to be that you'll be clueless on how to drive in snow.

Buy a cheap snow brush/scraper as soon as you get far enough north. The defroster will keep it clear when driving in all but the worst freezing rain (which you shouldn't drive in anyway) but you should scrape off the snow accumulation from all windows before you drive (good to sweep off hood and roof so that doesn't just blow onto winshield and rear window when you start). The batteries will be fine (unless that 12v was going to go bad soon), there are special winter blades, but you won't need them. The heater will keep you warm enough after the car is warm, but I'd keep the coat in the front with you.

Make sure the stuff in your windshield washer is good for cold... spray will get on your windshield constantly and you'll need to squirt a lot... you may have to fill the reservoir each fillup. Soapy water won't do! Buy stuff rated for cold! If your old southern version freezes in the tubes it won't thaw just because you add the right stuff to the reservoir later.