LOL. There's nothing classless about fitting a tire to the stock GT 7 inch rim, that the tire manufacturer says will fit on a 7 inch wide rim. Show me a corner that you can take faster in your CX-5, while not risking your driver's license and I will concede that what I did was "classless".
I have driven my CX-5 on the curvy 161 / I-20 interchange ramps (check google maps) at high enough speeds to test the tires and I can tell you cornering is not an issue with 245 width tires on the stock GT rims. It is especially interesting to see sedans who tailgate me then drop off as soon we start cornering on those said curvy ramps.
Anyway, all I'm trying to say is I've tried the setup and it works. I've asked Tire Rack prior to buying the tires and their customer rep said it will work with the stock GT rims. The tires are only 0.3% smaller in diameter than the stock sized GT 225 width tires. The tire manufacturer themselves specified a rim-width range of 7" to 8.5". Continental says this tire weighs, 26.6 lbs, Tire Rack says it weighs 27 lbs. It is just as heavy, if not lighter than a 225/55/19 Michelin Premier LTX tire.
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https://www.continentaltire.com/product/extremecontact-dws06-24550zr19-105y/?)
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Sorry yrwei52 didn't mean to derail your thread that is specifically on 225 width tire selections. I'll stop here.