Well, after all this time (had my truck for 7 months now) I have finally started using it for what I bought it for.... Pulling my boat (a very light one, only about 1000 lbs boat, motor, and trailer) long distances.

And I dunno'..... I was hoping for just a bit better. I got 15.75 mpg pulling mostly flat ground, at 60 mph, cruise control set. Yes, I did figure for the additional miles covered for my 33" tires, as opposed to the 29" stockers. {pretty substantial too.... 12% !}

Only thing I'm wondering about now is, I bet my truck was running (on that tank of gas) for a full hour, without even moving ! Why ? Well first off, I've been using my auto remote start in the morning, and its set for 12 minutes. I usually hop in it in about 10 minutes though, and take off.
But the other thing is, each trip, I'm putting my boat in the water, and pulling it back out. I'm fairly fast at this {quite a bit of practice :-) ...but if I have to wait on some dum-bass in front of me.......

So, I wonder how much 1 full hour of running without rolling costs me ?

If I could get 18 mpg towing my light boat, I'd be pretty cool with that.

Your thoughts ?

Thanks,
Fish

 

With your over sized tires your odometer is running slower not giving you an accurate reading. I have the same problem. I had 2 tuners that adjusted the speedo and I really didnt get much better mpg.

 

Waiting to see what my does soon. Just installed 18x9 series 079 with Michelin 275/65/R18s. So will this make me indicate more mileage or less on the odometer?

 

Vehicles burn about 1 GAL. per hour ideling.

 

Whew, lucky . I get like 11.5-12.5

 

I used some type of tire calculator a member listed here in another thread for my aftermarket tires to be able to adjust my speedo error also but don't get anywhere close to your 12%? My truck is a 2007 SCREW w/FX4 package and the software only went up to a 2006 model FX4 so i used that for my stock tires since mine came with the lift and 35's already on it from the dealer. I then put my new 35X12.5 R17's in the calc and it told be 8.4% low so i'm not sure how your getting 12% for 33'' tires? 15.75 would be phenominal towing anything especially with bigger tires!

 

Enter your stock size tire and new size tire and you'll get the % of error on your speedo.


I get 17.4mpg/highway on stock tire and unloaded truck. That's with edge evo on stage 2 and flowmaster 40 series muffler dump at the axel.

 

18 MPG towing something. I would be happy too. I cant even get 16 empty.

 

I have managed to get 19.4 a few 400 mile trips. Cruise set at 68

 

I didn't use (didn't feel like I needed to) and kind of tire size odo/speedo calculators.

I just multiplied my stock tires 29" x 3.14 (pi) to get 91.06" circumference

Then I multiplied my new tires, 33" x 3.14 to get 103.62"

Then I divided 91.06" by 103.62", to find that my truck is actually rolling 11.7% further (91.06" is 88.3% of 103.61"), with each revolution of my tires.

This has a direct correlation with my mileage..... So that I've actually driven 11.7% further, than whatever my odometer says I have. Also, if my speedometer says I'm going 55mph, I'm actually going 11.7% faster than that, or 61.4mph.

BTW, I have been taking this into account as well, and setting my cruise control at 55mph.... but maybe I should drop this to 54mph. I'm shooting for towing at 60mph. (already 5mph over the towing speed limit).

I drive around like a mad man, for a living, all week. When I get in my truck for a fishing trip, it's time to relax. Turn on the mobile concert, and put together a fishing plan for the day :-)

So, if I burn 1 gallon for my 1 hour of idling at the ramp.... remote starts in the mornings, etc. then I guess I am getting just over 16mpg towing the boat. Judging by others experiences, I guess this isn't too bad. I'm not really too surprised though, as 1) I tow as slow and mellow as possible, and 2) my boat is really light. I was hoping for more of course.

But anyway....

Peace,
Fish

 

same here! i absolutly cannot get better milage than about 12.7 city, and i only get 15.7 or so driving 300 miles across state (200 miles are flat) on cruise for basically the entire time!

 

If I tow just my 14' utility trailer empty my mileage drop's down to around 15mpg at highway speed's. With about 2 to 3k lbs. it goes down to around 12.5 mpg.

 

I get 12-13 empty without a trailer and mostly highway driving with my '08 so I sure wouldnt complain about 15 pulling a trailer.

 

I get about the same as you Chris, no better or no worse. Not too impressed either.

 

I may be wrong but aren't you going the wrong way? I put bigger tires on and my GPS said that i was going 65 when my speedometer was saying ~69. Don't bigger tires make your speedometer read faster than what it is going?

Could be very wrong...