what are the biggest size tire that fits under the 07 aveo sedan ?

Not the bigesst but I run 195/50's. Handling is good. My wheels are 15" boyd coddington wheels.

I ran a set of 215/50r16 Kumho tires on my 2007 Chevy Aveo5 back in 2008/2009 when I ordered new wheels from TireRack. The really hugged the road. You can see pics of them on my garage post. After those wore out. I chose to go with 205/50r16 tires because there are more options in that size. I have been running that size April through November ever since. The speedometer is only off by about 2-3 mph. When the speedometer registers 70 mph the GPS says it's going 72-73 mph. I used the stock steel 14" wheels for dedicated winter tires. I ran several sets of 185/65r14 Bridgestone Blizzak WS60 tires over the years. This winter I went with Nokian Hakkapalitta R3 in the same size. The Aveo5 now has more than 425,000 miles showing up on the odometer.