Upgrading Oem Rim Size

[denslexusgx470]

I tried doing a quick research about this but didn't find an answer so I'll just post a new topic.

I have a question about upgrading your rims to a size bigger than what you currently have. For example, I'm interested in upgrading my 18" LS rim to the OEM 19" LS rim. Upgrading from 235/50-18 18" OEM 9 spoke to the 19" 5 spoke OEM 245/45-19.

Aside from looks, does this change the handling/comfort of the vehicle? How about gas mileage? I have found a decent slightly used set of the 19" 5spokes that I've always wanted. I've inquired with my Lexus dealer about tires and I'm thinking of going with Michelin Pilot A/S that they're offering. The dealer will also transfer my TPMS sensors to the 19" rim.

Just wanted some feedback about this! I know that I'm going just for looks and ease of cleaning my wheels but I was wondering if there's an effect (according to Physics). Thanks!

[xxstewart]

I did a +1 rim upgrade on a BMW several years ago, and the change in the ride and handling with a shorter sidewall tire was very pronounced. More agressive cornering, but a very bumpy ride, and substantially less tire life. Since I can't see how cool I look when I'm driving my GX, paying $5K for custom oversize chrome wheels and low profile tires for others to stare at seems stupid. Call me Mr. Boring OEM.