10" wide wheels and 275/65/18 tires?

so i found a great deal on wheels. Also found tires but they are separate purchases. these are very wide wheels at 10". tires are rated for max 9.5" wheels. can it be done?

also i tow 5 days a week and am trying not to kill my towing power. gas mileage is 21mpg stock and 13-15mpg with my #4000 trailer. do i need to worry that these wheels and tires will be too heavy and affect my power for towing. stock 265/65/17 are 30.5 ish inches. these 275/65/18 are right at 32"

otherwise i dont really off road and this is pretty much a mall crawler. i have other toys to abuse in the dirt

 

the real question is will i notice wheels(rotational mass) that are 1" taller and 3" wider. along with a tire that is 1.5" taller while towing?