HAHA yeah right!

 

Constructive post. Have any evidence to back up your position?

 

I do.

How about the fact that 295's (33.5" tire) make mileage worse on an auto. I don't see how a 37" tire that weighs probably twice as much is going to actually HELP your mileage. Maybe it's magic!

 

Like jrussell said, its not typical to see any gains, at least with autos going to a bigger tire, the 6spd guys claim to squeeze another 1-2miles though with say 35s, but going to 37s, that tire weighs alot, and the autos typically dont improve mileage with bigger tires...

Im about to find out, ill be putting on some 35s in the near future, getting 16.5 mpg right now...

 

I would think about a lift of some type. A two inch body lift would probably be all you need. You hit a big bump or some mild offroad terrain and you will damge your body work and your tire on the front rear fender.

This is waht I like about the dodges. you can fit big tires with hardly any lift. Try that on a chevy....

 

Most of my driving is done on the highway at 65-70 mph. I doubt the weight of the tire has much affect on mileage in this scenario. My 37s are about two inches wider than 265s so the increase in wind resistance is probably marginal. My cruising rpm is under 2000 which I believe helps mileage. How many people on this board have expressed interest in higher gearing options for their 3rd gen?

There are so many variables between trucks, drivers, and conditions that I believe it is impossible to make a blanket statement as to whether or not increasing tire size increases or decreases mileage, but in my case it did.

 

Oh I know, thats why I said typically, just from the posts ive seen on here with automatic truck owners...
Like I said, im about to find out as well, 90% of my driving is highway 70-75mph, and itll drop my rpms some, but as far as getting 1-2 more out of it, ill just have to see, id like to but im not holding my breath...

The 6spd guys usually see an increase, but most of the auto guys on here saw a drop...
If youve had luck, thats great, im just giving observations based on other posts on here, people ive talked to...

 

You did not provide evidence, just an unsubstantiated statement. My milage went up. I currently get 21 mpg w/ my 35s on. This is not a 'best tank' number, but a true MPG as I keep track of all the fuel that goes into my truck. See my prior post "MPG Graph for last 53,000 Miles!" for the graph
https://www.dieseltruckresource.com/...d.php?t=129749

 

My mileage went down, probably by 2 mpg, when I went from the stock donuts to 325/70-17s (35's).

 

People love to make claims and then call them evidence. It drives a philosopher INSANE!!!!

As people said, the mileage gain (if any) will be seen on the highway. If you are the kind of driver that is always on the road for hours at a time, you are going to see MPG inprovements because the positives far outweigh the negatives. If your truck is a grocery getter, then you are likely to see MPG drops because the negatives will outweigh the positives. If you do a bit of both, it will probably be a wash but the looks and performance alone will be worth it! I do about 90% highway and I have seen my mileage jump from 13 to 16 and change.

Deere Nut: I think the wheel wells are the only DRAWBACK on these trucks. These beasts come with 31.6" tires stock and you can barely cram anything larger in there if you want a wide tire. I was able to run a 38x15.50 on my stock H2 with a little trimming in every situation but offroad, and with a 6" lift I could run them doing extreme offroad. To run 38x15.50 in all conditions takes like a 10" lift on these trucks and maybe even more modifications.

 

Yes - 2" leveling spacers in the front coils to match the ride height of the rear, which is kept at stock height by the airbags with all of the weight in the bed.

To keep the front end geometry stock, I made a combo 2" swaybar drop mount/Stainless Steel Steering Shaft Stabilizer, and welded a 2" drop mount for the trackbar to the frame, so the axle would remain centered between the framerails.
I trimmed the front rubber "air dam" with a new corner profile, and trimmed a concave radius in the lower rear edge of the front fenderwells' plastic liner; then I cut a small slit in the fenders' wheelwell sheetmetal to move the corner up and back a little.

I get 90% of lock-lock steering, and almost full articulation at full lock... if off roading is in your future, I'd recommend deeper backspacing or half-inch longer lower control arms. I can't get too crazy with that Brian, 'cause it throws the tools and the parts out of their places in the Job Boxes!
My BFG 315s already rubbed the lower control arms a bit, but the Toyos touch the control arms and the sway bar (opposite sides) simultaneously.

Thanks, D! That's high praise from you...

This is definitely NOT for the faint of heart! Even though I measured everything carefully before I decided to go this route, I changed my mind to the Toyos from the 37" BFGs after checking prices, but the Toyos are 13.5" wide - which is 1" more than the BFGs; when these 94# monsters showed up at my door from UPS, I thought " "
Every time I walked around them ('bout 3 weeks worth), they seemed to grow a little bigger!

I have a strict anti-lemming policy, so with all the debadging that's so prevalent, I decided to RE-badge my truck.

No, not magic - just physics.
I call these tires my 7th gear, since I don't have the urge to grab another gear anymore on the interstate when I'm already in 6th... I could get 17 mpg for a whole tank with my 315s, but these 37"s got me over 19 mpg over the Appalachians a few weeks ago, with a full bed putting my gross well over 10K#. The Cummins "sweet spot" is 1800-1900 rpm, so I kept it there. If I drove at 50-55 mph, I could break into the 20s easily, based on the testing we did in Virginia.

Shucks, half the reason I did this was because everyone said I couldn't do it w/o a lift... and I don't use the service trucks for serious off-roading due to all of the tools and parts in the boxes.

 

MD, I think that may be the biggest post I have ever seen !!

...And a very good one!

 

Your's went up because you have a 6spd. Mine went down because I have an auto. Two totally different animals. As already stated in this post, mileage will probably increase with the 6spd and decrease with the auto.

The claim is not unsubstantiated, it's what I experienced for myself first hand. So, what kind of "proof" do you guys require? Do I need to go get a set of stock tires and do some hand calcs on paper and then scan the "evidence" in and post it here? I guess I could even take pics at the fuel pump and video of me resetting the trip odometer. Would that suffice?

 

Yes it would. just don't confuse sufficiency with necessity!

 

Gosh, it's awfully swell to be best at something!