2007 to 2008 Touring Tire/Wheel Swap Question

No reason.

 

The answer will depend on the tires on your wife's 2007 and your 2008. With the stock tires, here is the important information:

2007 Prius Goodyear Integrity (185/65-15):
Overall Diameter - 24.4
Revolutions per mile - 855

2008 Prius Touring Edition Bridgestone Touranza (195/55-16)
Overall Diameter - 24.4
Revolutions per mile - 854

So, for the stock tires, they are interchangeable with no hit to speedometer or odometer accuracy. If you do not have the stock tires on the 2007, then you need to find out what the specification is for the tires that are presently on the 2007. As far as wheel fit, again, stock wheels are interchangeable between the two cars. Owners of non-Touring edition cars have swapped the wheels on their car for Touring edition wheels. The brake rotors, calipers and drums are the same parts between the base and Touring editions.

 

I have an 09 Touring, and to confirm what others have said, I bought 4 15" OEM Prius rims to put snow tires on. The wheels are entirely interchangeable. As apriusfan noted, the tires you list are within 1 rev per mile of each other.

Should you ever want to compare other tires, there is a "calculator" available at: Tire size calculator

One thing you should take into consideration is TPMS (tire pressure monitoring system). When you put "new" (ie, different) wheels on a car, they need to be set up to work with the car's TPMS system. If you switch wheels between the cars, it may be necessary to reprogram each car to read the "new" sensors on the rims just mounted. (The TPMS is built into the valve stem.) When I asked about the cost of reprogramming for my snow tires, my dealer said it was about $100. So, you might be facing a cost of ~$200 to reset the TPMS.

 

You have missed one important consideration. The tire pressure monitor will be upset. To fix that you will have to take the car to a Toyota dealer and have them reprogram the car for the different sensors you will end up with.

Note that, while unimportant in this case, the tire load carrying capacity is the most important factor when changing tire size. As both tire sizes are for the same car, in this case this isn't important.

 

Out of curiosity, what are you advocating using the tire calculator for?

Typically it has been used to get a close approximation of diameter and speedometer & odometer variance if the manufacturer does not publish a diameter specification for their tires. If the manufacturer publishes the diameter specification, that should be used instead of relying on the tire calculator, as tires having the same 'sizing' (e.g. 205/55-15) can have different measured diameter and revolutions per mile specifications.