Tow vehicle tire size not to spec

how is this thread still open?

^ OMG, lol! The "differences" you mention aren't even seat of the pants discernable. Even to a perceptive driver. What's even funnier is most vehicles come with several different "factory" tire/wheel sizes over the course of a particular vehicle platform and even offered with diffenrt combos any given year!

But, regardless the entertainment yall provide is priceless!
Ever watch Finding Nemo with your grandkids or great grandkids?
Remember the seagulls, who would at the sight of one fish, all jump up and go nuts and start yelling "Mine, Mine, Mine!" ? Even though most of them didn't even know what they were after?

I see the resemblance in these totally dead threads that in this case got brought back up by a spammer, and guess what? Yup, here comes all the RV net advice and warnings, as if there was even a question to begin with!

LOL, carry on boys, you add levity to me day, as I deal with some very obtuse people (State employees) all day long!

StirCrazy wrote:

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

I would somewhat agree with the idea to go back to the OEM size specified on the door sticker.

While it looks like there is very little difference, in reality that difference can alter multiple things seen like speedo and mileage readings and things unseen like handling, traction, braking, gear ratio.

Rather than guessing, one can lookup and compare with online tire size calculators.

Like THIS ONE

Select compare, input your OEM tire size and the new tire size and hit calculate..

I have copied a snip of the OPs tires..


Click For Full-Size Image.

The current tire the OP has is .4" wider than stock, has .3" wider sidewall, .5" taller, 1.7" in outside diameter larger and turns 10 revs less per mile.

While that all seems like it isn't much, it does affect (lower) gear ratio which reduces effective HP/tq getting to the ground and will affect the braking a bit.

It affects traction some with the wider width under some circumstances and may add some more turning effort for steering.

The additional sidewall can add more sidewall play which can result in feeling a bit more squirmy which can affect the overall handling than if it had OEM size tires.

There are various valid reasons why it has larger size, price point and availability may have played a big role to the selection.

Less valid reason is "looks", taller tire and larger side walls than OEM sizes looks much cooler to some folks.

I wouldn't replace them right now if they have good tread, just go back to recommended OEM size at next tire change.

GoodJ wrote:

Thermoguy wrote:
The real question on a towing forum is do the P rated tires work for your trailering experience? What weight of trailer are you towing? How do you use your expedition? Should you be considering an LT tire? You might want to upgrade to a better tire for towing if you are posting this on a towing forum vs an expedition forum...

This is an excellent question. I am sure a lot of people have experience with the P vs LT debate, and this is relevant to a lot of towing questions. Anybody want to share some experiences, observations, opinions, etc?

You joined to make this post? LOL
In the words of FJB..."C'mon man!"

I've often found a big price difference between tire sizes.

As someone earlier mentioned could be why they made the very very tiny tire size change. It's less than a mole hill size change nothing near a mountain.

Thermoguy wrote:
The real question on a towing forum is do the P rated tires work for your trailering experience? What weight of trailer are you towing? How do you use your expedition? Should you be considering an LT tire? You might want to upgrade to a better tire for towing if you are posting this on a towing forum vs an expedition forum...

This is an excellent question. I am sure a lot of people have experience with the P vs LT debate, and this is relevant to a lot of towing questions. Anybody want to share some experiences, observations, opinions, etc?

The real question on a towing forum is do the P rated tires work for your trailering experience? What weight of trailer are you towing? How do you use your expedition? Should you be considering an LT tire? You might want to upgrade to a better tire for towing if you are posting this on a towing forum vs an expedition forum...

^Yet taller tires an provide other advantages for towing or hauling, so like most things, “ok” is a pretty broad range and “optimum” is generally a pretty narrow range.

But to the OPs question, the 2 sizes he’s talking about will be realistically indiscernible to all but the most overtly literal rvnet members!

^ Some of that is not necessarily true.
Unless a person gps the speed against the speedo, it’s no guarantee that the stock tires weren’t a little off.
Many trucks I’ve had, actually corrected a slight speedo error with a slightly larger tire.
Too much worry about a little different tire size that is unfounded iMO