Matty-D

I put the 275/60R20 which were the same size tires from the factory and I’m using the stock rim. Would the RT’s make that much more of a difference?

Thank you! I know that GM puts the Duratracs on the Trail Boss but they are smaller wheels. I have a friend who has them on his truck and he averages about 16 mpg. I just didn't expect to have that much of a drop. I thought about just keeping them for the winter and then purchasing a new set of wheels/tires for the summer. Similar to these 285/45R 22, but not sure if the mileage will be better.

Hi, Looking to see if anyone has experienced issues with gas mileage after replacing factory tires on a 19 RST 5.3. I was due for an inspection and needed new tires. I replaced the factory tires with the Goodyear Duratracs Tire size 275 / 60 R20. Before new tires, I was averaging. 15-18 city and 19-22 highway. On long trips, I have hit 27.3. Since the new tires were installed my mileage has dropped significantly, I am now average. 10.2 city and the highest I can get with highway driving is just over 14. I also have a K&N cold air intake that was installed about 9 months ago, before the new tires my check air filter notification would come on about every 500 miles. Could this have something to do with it or is it just the new tires? Does anyone have any suggestions?