Different sized front and rear tires

Hey all, so obviously this is not for an AWD DSM, but for a RWD Cadillac. It needs rear tires but I don't plan on using these wheels for longer than just this summer, I've got winters on spare rims, so I'm looking for the cheapest fix for now.

The stock tire size for this CTS is 225/55R16. Now, I have 2 spare tires, 225/60R16. Is there anything wrong with running those in the rear? Will the car sit funny? I believe the suspension is auto leveling, but I don't want it to look like a damn rat rod or some sh!t haha.

Thanks for any info! Or if anyone in the Oshawa area has some 225/55R16s (just 2) for sale for a good price, I could grab them asap.

Disclaimer- I'm no expert

Most places recommend staying within 3% of the original size. Going to a 225/60/16 would be just over that at 3.44% or 22.5 mm taller tire. The "55" is sidewall height as a percentage of the width (55/100 x 225 = 123.75mm) The 60 measures up at 135mm.

Most online tire sites have a tech section with calculators to show all the differences between sizes. You might want to check one out.

You could have ABS or VSA issues. I am not familiar with Caddy and honestly I never plan to be. 1/2" might be enough difference from front to rear to set off the abs sensors, then again you might fine.

That's the only thing I was worried about, don't want to set off any sensors and also don't want it to look funny. Figured I'd ask in case anyone else has come across it.