Hey Everyone,

I have a deal for a f-250,4x4 black with chrome package Lariat. My question is this truck comes with 20 inch tires, appear to be off road type, will the 20 inch tires have that large of an impact on mpg verses the 18s and do you think with the 20s I would have an issue taking it through a car wash as far as fitting on or in the track you need to line the tires up with to go through.

thanks for the help in advance.

 

Tire size affects all that, not wheel size. 20s are find for street use and won't affect your mileage hardly at all. I would say not at all, but some people will say a little due to increased rolling mass. If you ever plan on offroading you'll want 18s instead of 20s for better sidewall flex.

 

thats right, tire size affects the mpg's not the rim size. the rim offset combined with the width of the tire might effect the truck getting into a carwash's track though.

 

An engineers OPINION:

If I were in your shoes and looking at a new truck from a dealer, I would INSIST on making a tire/wheel swap to 18's a part of the deal.
18's are far more functional.
- Tires are much less expensive
- For a given overall diameter, 18's weigh several pounds less per wheel. And this is unsprung weight - the worst of all.
- Lighter means better acceleration, AND less fuel to get up to speed,
- Lighter means better braking and less brake wear
- FAR better for off roading. I like an absolute minimum of 8" of sidewall on a truck. With 20" wheel, that means 36" or taller tire.
- Better ride quality due to sidewall compliance.
- All things being equal, higher load capacity for a given construction.
Most of these are pretty subtle, but they all add up to make it a simple form needs to follow function decision for me!
I can't see any reason for the dealer to refuse - they can turn around and sell the 20's as an "upgrade" to somebody else. If fact, you should be able to negotiate a discount if they swap.

The BIG blingy wheels has been a hot fad for the last few years, but it has clearly gone into the realm of the absurd with function being seriously compromised for "style" - the primary indicator that a fad has "jumped the shark" and is going to die. That means that 18's may actually be better for re-sale in a couple years.

I love my 16's. But with the larger brakes on the new trucks, you can't go that small. But I recommend going as small in diameter as you can fit on a truck. Different story on a car for roadracing....

 

Just fyi, my stock 20's aluminum, weigh less than my stock steel 18" spare. I was shocked too, but I weighed 2 of my stock tires (1 flat, 1 full), and my spare, and it turned out that the spare was about 15 lbs heavier, which I didn't beleive, so I weighed everything 3 times and it turned out that the aluminum 20s weigh less than the steel 18. The spare did have slightly more tread on it because it had never been used, but the 20" tires still had at least 60% tread left.

 

I measured the overall height of the 18's and 20's at the dealer before i bought my 08. The 20's are only 1/2" taller than the 18's. I went with the 20's because they seem to match the trucks size.

 

Steel wheels will weigh more than aluminum, but you're right, that is a huge difference! Ford must be giving you a seriously beefy wheel on the spare!
I am assuming these are the same load ratings?

 

If you are talking about OEM 20" .vs OEM 18"...then you should have no issues going through a car wash.

Now...if the 20" are after-market, then the width of the wheel is a definite consideration.

IMO...the OEM 20" are a good combo for the '08 SuperDuties.


biz

 

Yep, the spare has the same BFG tire as what is on the truck.