Tow vehicle tire size not to spec

davehultin wrote:
I'm looking to replace the tires on my tow vehicle (2010 Ford Expedition) and I was surprised to learn that my existing tires do NOT match the tires specs on the vehicle placard. I don't know when or why that happenend. Anyways...

Placard specs are P255/70R18
Existing tires are P265/70R18

So my existing tires are 10 cm wider than what's specified. Is that a bad thing? Or just a "thing?"

My Expedition is no champ for gas mileage, but does that extra 10 cm per tire take the mileage down significantly?

In your opinion, should I return to specs when I replace the tires, or is there a compelling reason to stick with the wider tires?

I would put them back to factory size as right now they are taller , but it is only 10 mm not 10 cm so its not a huge deal but your spedomiter will be out a little and you milage wont be accurate. I wouldnt go out of my way to do it but next time you change tires out .. as for fuel milage I have had some cars that didnt care about bigger tires and some that just hated them and gas milage dropped significantly, that was a little more of a change then what you had on an older f150 but I had to go back to the factory size on that one it was so bad.

Steve