I have a 2005 S type 4.2 with 17" Juno rims. Can I replace them with 18" Triton rims with no issues at all?

I believe the Tritons are a bit thicker (245 40 vs 235 50)

Can a local mechanic just swap them out for me?

Thank You all

Happy New Years as well !

 

With suitable tyres (tires) and be aware the ride will be harsher.

 

Not only what John said...but buy 6 or 8 Tritons, not 4. You'll need 'em. I have two that are cracked, letting all the air out. The 03 has proper 16" tires/wheels fitted - far more refined ride and significantly more miles but no busted wheels.....