MPG improved with heavier tires???

[tragusa3]

Our F150 came with the stock P rated, SR-A Wranglers.

I didn't think they were as bad as most people claim, but if I needed new tires, why not try to eek out some improvement? So I debated going with another P tire or an LT. I ended up going with the Michelin Defender LTX M/S in an E load range.

From all of my research, I was expecting a bit stiffer ride, which I have now experienced and appreciate. I was also expecting to lose roughly 1 mpg due to the heavier tire. I stayed with the same size.

However, after 3-4 weeks, what I'm getting is about a 1-2 mpg increase on my work commute and a 4mpg increase on highway driving. A recent trip from Greenville to Gatlinburg (through the mountains on I40) I returned with a 23.5 mpg average on the truck computer (which is confirmed accurate).

What's going on? Could the quality of tire make that much difference? Less rolling resistance? Is the tire a different diameter and throwing off the computer? Whatever the case, I'll certainly be happy at around 23mpg on highway trips.

BTW, love the tire. Handling and noise are noticeably improved.

[tragusa3]

pbarnette, you are correct on my tire size.

Wes, very interesting post. My older P rated were at 38psi most often. Currently, these nwe ones are at 45psi. Not much more. I am going to experiment by bringing them up to about 65 and see if I see a change on my commute.

[Wes_Tausend]

I believe that harder tires can get better mileage. Some extreme mpg contests have been won by filling tires with concrete.

I worked on a railroad and steel tires on trains get the equivalent of about 400 mpg. Of course each car is also drafting the other, the key. But on level track, one man can move an empty railcar (say 20 tons) by pushing on it. It seems like it takes forever for it to start, but finally moves, then rolls quite a few feet on it's own before stopping. Low rolling resistance. We occasionally did that while switching to gain a few more feet of clearance for an adjacent track.

Also have purposely considered low rolling-resistance specs for replacement tires on our first Prius. So far the newer one ('15) seems to outdo the old one by about 4 mpg, averaging 50+ mpg vs 46+ mpg on the 2007. I think it's all due to a more complicated computer algorithm though, as to whether the engine runs or battery kicks in.

Wes
...

[pbarnett85]

I'm going to assume here that your F-150 came with 275/65R-18 since its 4wd and looks like it has the 18in wheels in your profile picture. On my 2010 F-150 2wd I had 265/60R-18 michelins that were about 30.5 inches in diameter and i replaced them with michelin LTX M/S2 LT275/65R-18 that were 32.1 inches in diameter. These were labeled by michelin as a low rolling resistance tire. After I adjusted my speedo for the larger tires I was still able to get 19.5mpg hand calc. hwy milage. So, i would believe it if you were able to pick up a few mpg on the highway with the michelins. They are a great hwy tire with great wet and snow traction.

[Chuck_thehammer]

tire deflection under weight.
inner tire construction, Comfort or for weight.
truck tire construction is designed to have less cord flex... less deflection and less heat.

and with a possible difference in P tire and LT tire overall Size.

check your odometer to road mile markers.. then adjust your numbers.

[mich800]

Fisherman wrote:
Actually the Michelin LTX series is known to gain a couple miles per gallon, not from being smaller in diameter, but better quality. As soon as the Good for a year SR-A's are worn on mine, I'll go directly back to Michelins.

Just to be clear. Better, or different mpg on different tires is not an indication of quality. Only that different intended compromises between traction, tread life, on road or off road bias, and a multitude of other factors can impact mpg.

[tragusa3]

I'm not sure what of all the above opinions is truth, but I tend to believe that there is an actual gain. Maybe not the full amount...no way of knowing. But I can feel a difference in rolling resistance. I can hold speed with less taps of the accelerator, and it does coast further. I know many will doubt that this can be felt.

[Fisherman]

Actually the Michelin LTX series is known to gain a couple miles per gallon, not from being smaller in diameter, but better quality. As soon as the Good for a year SR-A's are worn on mine, I'll go directly back to Michelins.

[Turtle_n_Peeps]

However, after 3-4 weeks, what I'm getting is about a 1-2 mpg increase on my work commute and a 4mpg increase on highway driving. A recent trip from Greenville to Gatlinburg (through the mountains on I40) I returned with a 23.5 mpg average on the truck computer (which is confirmed accurate).

There could be lots of things that account for the mileage increase. The bottom line is this. Those tires did not increase your mileage this much.

If it were that easy to increase mileage on a truck by 4 MPG or even .5 MPG the manufactures would pay $1000 bucks a piece for those tires.

My guess is your tire diameter messed up your mileage calculations.

[fla-gypsy]

Check the published tire diameter

[donn0128]

Tread pattern, tread compound all play a role. Unless you know for certain the tire diameters are exactly the same you simply cannot compare.

[fj12ryder]

It's possible that the tire diameter is a tad smaller and you're covering the same distance, but it's showing more miles on the odometer, hence it looks like you're getting better mileage. Not unusual for tires labeled the same size to actually measure a bit difference in diameter.

[downtheroad]

Your new tires, higher air pressure = less rolling resistance.

[RoyB]

I also get better gas mileage using the SHELL Gasoline for some reason...

Roy Ken

[Artum_Snowbird]

I would imagine it's similar to pushing a loaded wheelbarrow with a soft tire compared to pushing one with a hard one.

I put Defenders on our Rav4 (not LTX) and we really like them too.