Originally Posted by Abbeyroad2
Currently the truck has 225/70R19.5 but I would like to put the larger 245's on.
The stock-size tires have all the weight capacity you need unless you severely overload the truck.
Does the additional 1.4" in diameter make any real difference or create interference issues
Interference you can tell by looking at the current tires. If you have at least an inch of clearance all around now, then the taller/wider tires should not cause an interference problem.
The big difference is in tire revolutions per mile (revs/mile) because of the taller tires, and a slight decrease in MPG because of the additional aero and mechanical drag of the taller/wider tires. For Michelin XZE tires, 225s have 646 revs/mile. 245s have 617, or 4.1% difference. That means your speedometer, odometer, tripmeter, and effective rear axle ratio will all be different by 4.1%. Assuming your speedo is accurate now, it will be 4.1% slower with the taller tires. So an indicated 70 MPH will be an actual 72.87 MPH on Officer Bob's radar gun. 400 miles on a tank of fuel would be an actual 416.4 miles, so your hand-calculated MPG would not be very accurate. And if your truck is the fancy trim including a lie-o-meter that shows MPG, it will be even further off than it is now.
If you now cruise at 2,400 RPM, you would have to cruise at 2,301 RPM to make the same actual speed. Whether that matters depends on the HP and torque curves of your engine.
Michelin also makes the XRV tread in that size. The revs/mile difference is only 3.1%, so consider the Michelin XRV if you decide to move up to the 245s.
Personally, I've ran taller tires on my diesel tow vehicle, and didn't like the effects, even with a corrected speedo. So I now buy the best tires I can get in the stock size. That's usually a Michelin of some sort.