If I went from 18" wheels to 19" wheels would I have to adjust the alignment on my car?

 

You can only adjust toe in / out unless you have an aftermarket camber / castor kit.

Do it - it should only cost about $20 and takes about 10min.

 

So if I wanted 19" rims, but I wanted to put racing tires on the old 18" rims and switch them out for every race that would be a bad idea?

 

You don't need an alignment if you switch wheels, unless you dramatically change the circumfance of the tire.

Rule of thumb is for every inch you got up on the rim, go down 10 on the series of the tires (ie 225/45/18 to 225/35/18)

 

Right on. Thanks.

 

Got new wheels and this is my question to you guys. The tire diameter in the front is the same. The rear tires are around .75" larger now...
I will be rotating tires out every winter season. Stock w/snow tires Thanksgiving to Easter roughly.

Should I get those re-aligned every season or not?