P0500 OBD-II error/freakout - tire size related (mismatched sizes)?

[Top_Fuel]

Is it? ... My spare is a 115/70r14.

I assumed the spare was the same (at least close?) to the diameter of the stock tires. I guess it's close enough since the car doesn't have a limited slip differential. I sometimes think that every car is equipped with a Detroit Locker.

If a Mirage spare is a 115/70/14, then my 185-60-15s are roughly 3.5 inches taller than that. I would not put 2 tires with that much size variation on the drive axle...unless I was just limping the car down the road to a tire shop. In theory the Mirage's differential is not a limited slip and would handle the size variation...but I would rather take an extra 5 minutes to put the spare on the rear of the car and not worry about it.

Some size variation is OK since they assume you won't drive faster than 50 mph and you won't drive very far (and the car has an open differential).

If Top Fuel would try 185/65r15 tires next...

LOL...someone else is going to have to try that combination. I won't own this car long enough to put a second set of new tires on. I will probably give this car to one of my nieces before it needs a new set of tires.