Hey guys,

I just recently purchased a 2011 f150 5.0 XLT with the XTR pkg super cab 4x4 3.55 L/S, I purchased this truck in Alberta Canada I reside in Langley B.C. (Vancouver) on my trip home I averaged an astonishing to me 11.6l 100/km (20.3 MPG) through mostly steep mountainous highway. I bought this truck to replace my 2006 f150 lariat 5.4 which i had just recently installed a new set of 10ply 285/65r18 good year wranglers, I am considering having these tires swapped over to replace the almost warn out factory tires on the 2011 but I am concerned how significantly this might effect the MPG and towing performance of my new 5.0 (travel trailer weighs 4500 ibs). If any one has some input or has made similar changes, I would like to hear your experiences.

Thanks, Miller.

(I have searched but am unable to find anything not pertaining to the Ecoboost)

 

Look up the weight difference between the two tires. That will be what drags you down the most. Also, look at the weight ratings of a 10 ply tire and compare that to what your axles are rated for. In most cases an XL rated tire is rated for more than a semi float 1/2 ton axle can safely handle.

 

Thanks Wookie,
According to tire rack the factory tires are 43ibs each and the wrangler 10plys are 56ibs each. I take it an extra 13ibs of un sprung weight per tire is enough to make a significant difference in both power and fuel economy?

 

I run a set of nitto trail grapplers 285 65 r18 but on a 18x9 rim with 5 back spacing 0 offset. Same spec truck but stx model, I lost 1 mpg. I switched back to stock tires / rims before winter and gained 1 mpg within a week driving the same roads. I have a 2 inch level kit on mine. You might rub without a level kit turning at full lock but not sure. Maybe someone can chime in.

 

Could I ask why you bought 10 ply (Load Range E) tires for an F150? Is your 4500 ibs in pounds or kilograms? If in pounds (lbs) than a standard P rated or 4 ply LT tire would be a better replacement that will be lighter and give better mileage.

 

On my 2011, I replaced the 9 lb lighter OEM tire with the same size but heavier Toyo tire. Also slightly wider. Lost about 1.2 mpg. I think you can expect that and maybe more. You can calculate the extra fuel cost and see if that is offset by what you would lose running the 10 plys.