Convert Vibe GT from 18" to 16 or 17"?

My daughter’s 2009 Vibe GT came with 18" wheels. I’m thinking of buying new 16 or 17’s to replace the 18’s. The tires are cheaper and cushion the ride more. Since we’ve already replaced one of the OEM rims from her hitting a pothole, the larger tire height seems sensible to me. I found a tire diameter calculater. I figured the 18’s as having a diameter of 25.74, 16’s-25.02, and 17’s-24.74 (all with recommended tire sizes). Is the difference enough to worry about and can I get a 16 or 17 tire that will get closer to the 18 number? Anything else to think of? (stock shocks on GT vs. lower model etc). Thanks for looking!

I bet has the info you need. The base vibe probably came with 16 or 17s, and tirerack will give you the appropriate size. You could even buy everything there, get a set of mounted, balanced tires and wheels at typically a good price.

Here’s a look at the spreadsheet I used to calculate the diameters. I used recommended tire sizes from the website.

Both Tirerack and a local dealer told me I can do it, but I just want to make sure if it’s ok with a small diameter difference. Thanks.

If tirerack said it was ok, then I’d do it. There will always be a small difference between sizes.

205/55/16 is the original size for the base Vibe/Matrix and that should be OK in your case.

215/45/18 is the oddball, IMHO

the diameter difference between the 16 and 18 will make the speedometer read ~2 MPH different at 60 MPH.

I have 16" rims on my Matrix and wish it had 15" for the same reasons you state.