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 > Tow vehicle tire size not to spec

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davehultin

Fargo, ND 58104

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Posted: 07/29/21 06:54pm Link  |  Quote  |  Print  |  Notify Moderator

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?


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2010 Ford Expedition, 2018 Gulfstream Cabin Cruiser 28BBS

enblethen

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Posted: 07/29/21 07:22pm Link  |  Quote  |  Print  |  Notify Moderator

I would not worry about that small difference. Make sure ratings are the equal.
They may also be an option, but that little difference I doubt it.


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KD4UPL

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Posted: 07/29/21 08:16pm Link  |  Quote  |  Print  |  Notify Moderator

I suspect the vast majority of vehicle that have been around as long as that vehicle have different size tires on them than what came form the factory. It's quite common to change for a variety of reasons.
The extra width isn't hurting anything. Technically that tire is slightly taller too but almost immeasurably so considering tread wear.

Grit dog

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Posted: 07/29/21 11:59pm Link  |  Quote  |  Print  |  Notify Moderator

Dude, they’re 1cm wider. (And about a half inch taller or less than 2 cm if we’re still using the queens units.lol)
You’ll notice virtually no difference


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Mike134

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Posted: 07/30/21 05:12am Link  |  Quote  |  Print  |  Notify Moderator

davehultin wrote:


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?"



As others have said just a just a thing. Perhaps the P265 can be bought at a cheaper price.


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Huntindog

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Posted: 07/30/21 05:16am Link  |  Quote  |  Print  |  Notify Moderator

KD4UPL wrote:

I suspect the vast majority of vehicle that have been around as long as that vehicle have different size tires on them than what came form the factory. It's quite common to change for a variety of reasons.
The extra width isn't hurting anything. Technically that tire is slightly taller too but almost immeasurably so considering tread wear.
???? Does treadwear not happen on the other size?


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Huntindog

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Posted: 07/30/21 05:25am Link  |  Quote  |  Print  |  Notify Moderator

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?It will reduce MPGS for sure, especially when towing

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 gather you bought it used? If so, then the PO upsized the tires. It is a real popular thing to do on trucks.

You should be aware that a larger tire will reduce your tow rating. The factory rated it according to the factory size. While this is of little concern to those that do not tow, it could be for those that do. Just how much it will affect the rating is anybodys guess, But the fact that it WILL decrease the row rating is not subject to debate.

Since you tow, you likeley want all of the performance that you can get... That means put the factory size tires on it,


CapriRacer

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Posted: 07/30/21 05:27am Link  |  Quote  |  Print  |  Notify Moderator

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?


Sometimes the OEM supplies wheels that are barely wide enough for the specified tires. That would mean that upsizing a tire might result in more center wear.

But that is not the case for your vehicle. It came with 8.5" wheels and a P265/70R18 can be used on up to a 9" wheel.

Fuel economy?

First, tire rolling resistance varies a lot between make/model - much more than mere tire sizing changes do!

Secondly, the 265 has a larger diameter which should help fuel economy.

Thirdly, Worn tires have less rolling resistance than unworn tires do - all other things being equal. So expect a loss of fuel economy when you change tires.


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valhalla360

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Posted: 07/30/21 05:58am Link  |  Quote  |  Print  |  Notify Moderator

Huntindog 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?It will reduce MPGS for sure, especially when towing

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 gather you bought it used? If so, then the PO upsized the tires. It is a real popular thing to do on trucks.

You should be aware that a larger tire will reduce your tow rating. The factory rated it according to the factory size. While this is of little concern to those that do not tow, it could be for those that do. Just how much it will affect the rating is anybodys guess, But the fact that it WILL decrease the row rating is not subject to debate.

Since you tow, you likeley want all of the performance that you can get... That means put the factory size tires on it,


Technically true but for this situation, it's a small enough change to be largely irrelevant to the OP. The radius of the tire is only 0.7cm larger than stock.

This is an issue for guys with a jeep where they replace the stock tires that may be 24" outside diameter highway tread and upgrade them to something crazy like 36" outside diameter knobby balloon tires. These guys will see a big impact on MPG and tow capability.


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JIMNLIN

Oklahoma

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Posted: 07/30/21 07:48am Link  |  Quote  |  Print  |  Notify Moderator

Quote:

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

The wifes 2016 1500 chevy crew cab short bed 5.3 engine 6 speed tranny aluminum wheels came with P255/70-17" tires.
After 42k miles it was time to replace them.
The 255/70 size doesn't have a very big selection in the tread type/design I use.
The P265/70-17 has a huge selection so went with the P265/70 size in the tread design I wanted.

No difference in mpgs.
No difference in towing performance pulling a 10k car hauler with various equipment on the deck.
No difference in braking.
No issues with matching wheel width vs tire tread width
There simply isn't that big of a difference in a 255 vs a 265 tire to cause issues for my use.
More than likely your previous owner found the same thing when his tire replacement time came.


"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers

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