Yeah, the difference is pretty big. I live in Finland so I have two sets of tires; 17" with summer tires and 16" with winter tires. I got the deflation warning a couple of times after changing between the sets, and knowing how the system works, decided to do a bit of calculation.
In 16" size, for every 360° rotation the rear tire does, the front tire does 362°.
In 17" size, for every 360° rotation the rear tire does, the front tire does 371°.
No wonder the system throws a fit due to such a change.
I thought the 17" rear tire size choice of 225/45R17 was weird, since 225/40R17 would be far closer in circumference to the front 205/45R17...until I tried to find such a tire online.
