I just put some continental winter extreme contact tires (LT245/70r17) on my 2011 super crew cab ecoboost. I think they look a little small and I should have put the LT265/70r17 on instead. I was just wondering if there would be any difference in performance between the two tire sizes like one might have better fuel economy. My fuel economy around town has gone from 14.3 liters per 100km around town to 15.1 liters per 100km since I put them on a week ago. I guess that is to be expected from winter tires. Lets hear some input from the real know it alls and not the fake know it alls please.

 

Theoretically, narrower tires are better in snow, but then I don't claim to be a sknow it all.

 

Correct, narrower is better in snow.

To the OP, the reason you are getting better gas mileage is that the new tires are smaller than your summer tires (assuming the summers are 275) and the speedometer has not been corrected.

 

smaller tires = less weight. Not much but every pound matters.

at the same time you just changed your RPM's due to more revolutions per mile from smaller tires so your highway mileage might suffer while your city should increase.

 

Kingfish, he's getting worse mileage - more liters per 100 kilometers.........

14.3 L per 100 km = 16.9 mpg US.
15.1 L per 100 km = 15.7 mpg US.

What exact size are your summer tires?

 

My summers are the stock good year p275/65r18.

 

Sorry, I misread that one.

The fact he went from a P series to an LT will also cause lower mileage. However, LT series tires have other benefits.

 

I'm gonna put winter tires as well. Its just a good idea.

 

me to. damn canadian math

 

Stock Tire - 275/65R18
Revs per Mile: 648.5
Actual Speed: 60 mph 100 km/h


Tire 1 - 245/70R17
Revs per Mile: 681.9
Speedometer1: 63.0 mph 105. km/h

Tire 2 - 265/70R17
Revs per Mile: 658.2
Speedometer1: 60.8 mph 101. km/h

Tire 3 - 285/70R17
Revs per Mile: 636.0
Speedometer1: 58.8 mph 98.0 km/h


I put 285/70/17 on mine. I did that before I got my tuner. My thought pattern was simply that When your speedo and thus the odometer are off, I would rather have it off in my favor. Running the winter tires you have, for every 5000 km of actual distance traveled, you are adding 5250 km to your truck odometer. I didn't feel like adding extra mileage for nothing. As it sits, the 285/70/17's work out to for every 5000 km of actual distance, the odometer reads 4900 odometer km.

Along with the odometer troubles, comes the fact that your truck is going through its shift points based of wheel speed, and rmp. With such a large difference in tire size, your computers are getting the wrong information to begin with, and you should probably see some significant power differences. Truck thinks it is going faster than it really is, therefore it shifts gears sooner than it should. I may be wrong on this, but it theoretically should be perhaps a little better on actual mileage, but the trade off is a slug of a performer. There may very well be a boat load of info I'm missing on this. Just a personal theory. I'd be willing to bet that any stock 5.4 would eat you for lunch right now. Any buddies with a 5.4 who you could have a quick race with and find out? That would be a pretty youtube video. I could see it now ....... 2010 5.4 kills 2011 EB

I'm guessing the reasons you chose the 17 inch wheels for winters, like I did, were price and availability in the used wheel market. The sad part is that you cannot find a tuner for the '11 EB to correct for tire size, like I did for my '10 5.4. I think my best suggestion to any future EB owners who want to run winter rubber, is to pay the few extra bucks, and buy stock sized wheel and tire combo's. It will probably save you money in the long run.

 

I am going to phone to see the return policy on my tires, I was thinking of getting the continental extreme winter contact LT235/80R17 instead of keeping my LT245/70R17. The difference is the 235 diameter is 81.5 cm and the 245 is 77.5 cm. I was just wondering on the website it says rim widths 6.0-7.5 is that the range it means it will fit. Cause my steel set say 17*7.5 so I am assuming they will fit.

 

The Bridgestone blizzak DMV1 should be available in a 255/75/17, and from this Canadian website... http://www.1010tires.com/tire.asp?ti...lizzak+DM%2DV1 too. Size wise, they are about as perfect a match as you can get in a 17 inch tire.

Stock Tire - 275/65R18
Revs per Mile: 648.5
Actual Speed: 60 mph 100 km/h

Tire 1 - 255/75R17
Revs per Mile: 648.9
Speedometer1: 60.0 mph 100. km/h

Buy em early, they sold out last year when I wanted mine. None in the country.

And The DMV1 got awesome ratings compared to most of the competition.

 

When replacing tires try to keep the same outside diameter as the O/E was on the vehicle. My 010 came with 275 55 R20's and I replaced them with 265 70R17 winter tires and wheels. There is less than 3/8 inch difference in the diameter so there will be no issues with the speedo and other computer functions that rely on wheel revolutions.

10 10 wants way too much $$ for their tires.
I Ordered a winter set up from Discount Tire Direct and the price was 600 dollars less than the same tire and steel wheels from the Ford store.
Here are some pictures of what got, Hankook I*Pike RW11 tires on V Tec wheels.

 

I just picked up Michelin Lattitude xice xi2 on ford steel 17" and TPMS. Tire size is 265/70/17. This is the package the dealer recommended and my previous xice michelins were outstanding. Haven't mounted them yet but I'll let you know once I do.

 

The recommended psi on my door is 35 psi. That is for the p275/65R18 stock tires. Do I use that for my winter tires as well (LT245/70R17). The front tires look like they are under inflated when I use this psi. I did fill my tires up when they were cold and I am also using a digital pressure gage.